EXECUTIVE DIRECTOR OF THE DEPARTMENT OF CONSERVATION AND LAND MANAGEMENT

Jurisdiction : SUPREME COURT OF WESTERN AUSTRALIA

Citation : SOUTHERN PROPERTIES (WA) PTY LTD -v- EXECUTIVE DIRECTOR OF THE DEPARTMENT OF CONSERVATION AND LAND MANAGEMENT [No 2] [2010] WASC 45

Torts - Negligence - Public authority - Prescribed burning and smoke damage to grapes - Whether a duty of care - Whether non­delegable - Whether breach of duty - Application of Civil Liability Act 2002 (WA) - Nuisance - Whether pleaded - Whether Civil Liability Act applies to cause of action in nuisance - Immunity of employee - Whether employer immune

Civil Liability Act 2002 (WA), s 5B(1), s 5B(2), s 5U, s 5W, s 5X

Conservation and Land Management Act 1984 (WA), s 5 , s 18, s 19, s 32, s 33, s 36, s 38, s 54, s 55, s 57, s 58, s 60, s 132

Crown Suits Act 1947 (WA), s 3

First Appellants : Mr M M Mony De Kerloy & Mr P J Hannan

Second Appellants : Mr M M Mony De Kerloy & Mr P J Hannan

First Respondent : Mr R M Mitchell SC & Mr B P King

Second Respondent : Mr R M Mitchell SC & Mr B P King

First Respondent : State Solicitor for Western Australia

Second Respondent : State Solicitor for Western Australia

Sullivan v Moody [2001] HCA 59

Adeels Palace Pty Ltd v Moubarak [2009] HCA 48; (2009) 239 CLR 420

Associated Provincial Picture Houses Ltd v Wednesbury Corporation [1947] EWCA Civ 1; [1948] 1 KB 223

Bader v Jelic [2011] NSWCA 255

Bankstown City Council v Alamdo Holdings Pty Ltd [2005] HCA 46; (2005) 223 CLR 660

Bell v Western Australia [2004] WASCA 205; (2004) 28 WAR 555

Benning v Wong [1969] HCA 58; (1969) 122 CLR 249

Bridgetown/Greenbushes Friends of the Forest Inc v Executive Director of the Department of Conservation and Land Management (1997) 18 WAR 126

Briggs v Lunt [No 3] [2011] WASCA 44

Brodie v Singleton Shire Council [2001] HCA 29; (2001) 206 CLR 512

Burnie Port Authority v General Jones Pty Ltd [1994] HCA 13; (1994) 179 CLR 520

Caledonian Collieries Ltd v Speirs [1957] HCA 14; (1957) 97 CLR 202

Chief Executive Officer, Department of Environment and Conservation v Szulc [No 2] [2011] WASC 315

Clambake Pty Ltd v Tipperary Projects Pty Ltd [No 3] [2009] WASC 52

Cole v South Tweed Heads Rugby League Football Club Ltd [2004] HCA 29; (2004) 217 CLR 469

Commonwealth v Introvigne [1982] HCA 40; (1982) 150 CLR 258

Crimmins v Stevedoring Industry Finance Committee [1999] HCA 59; (1999) 200 CLR 1

CSR Ltd v Della Maddalena [2006] HCA 1; (2006) 80 ALJR 458

Delaware Mansions Ltd v Westminster City Council [2001] UKHL 55

Department of Housing and Works v Smith [No 2] [2010] WASCA 25; (2010) 41 WAR 217

Do Carmo v Ford Excavations Pty Ltd [1984] HCA 17; (1984) 154 CLR 234

Drexel London (a firm) v Gove (Blackman) [2009] WASCA 181

Edwards v Blue Mountains City Council [1961] NSWR 803; (1961) 78 WN (NSW) 864

Fox v Percy [2003] HCA 22; (2003) 214 CLR 118

Geddis v Proprietors of Bann Reservoir (1878) 3 App Cas 430

Graham Barclay Oysters Pty Ltd v Ryan [2002] HCA 54; (2002) 211 CLR 540

Hackshaw v Shaw [1984] HCA 84; (1984) 155 CLR 614

Haris v Bulldogs Rugby League Club Ltd [2006] NSWCA 53; [2006] Aust Torts Rep 81-838

Hazelwood v Webber [1934] HCA 62; (1934) 52 CLR 268

Hunter Area Health Service v Presland [2005] NSWCA 33; (2005) 63 NSWLR 22

Kuhl v Zurich Financial Services Australia Ltd [2011] HCA 11; (2011) 243 CLR 361

Manchester Corporation v Farnworth [1930] AC 171

McKell v Rider [1908] HCA 9; (1908) 5 CLR 480

Melaleuca Estate Pty Ltd v Port Stephens Council [2006] NSWCA 31

Miller v Miller [2011] HCA 9; (2011) 242 CLR 446

Modbury Triangle Shopping Centre Pty Ltd v Anzil [2000] HCA 61; (2000) 205 CLR 254

Network Rail Infrastructure Ltd v CJ Morris (t/as Soundstar Studio) [2004] EWCA Civ 172

Parker v The Commonwealth [1965] HCA 12; (1965) 112 CLR 295

Pyrenees Shire Council v Day [1998] HCA 3; (1998) 192 CLR 330

Roads and Traffic Authority of New South Wales v Dederer [2007] HCA 42; (2007) 234 CLR 330

Rylands v Fletcher [1868] UKHL 1; (1868) LR 3 HL 330

Shaw v Thomas [2010] NSWCA 169

State of New South Wales v Lepore [2003] HCA 4; (2003) 212 CLR 511

Stevens v Brodribb Sawmilling Co Pty Ltd [1986] HCA 1; (1986) 160 CLR 16

Stuart v Kirkland-Veenstra [2009] HCA 15; (2009) 237 CLR 215

Sullivan v Moody [2001] HCA 59; (2001) 207 CLR 562

Sutherland Shire Council v Heyman [1985] HCA 41; (1985) 157 CLR 424

Sydney Water Corporation v Turano [2009] HCA 42; (2009) 239 CLR 51

Tame v The State of New South Wales [2002] HCA 35; (2002) 211 CLR 317

The Commonwealth v Introvigne [1982] HCA 40; (1982) 150 CLR 258

The Finance Brokers Supervisory Board v Van Stokkum [2006] WASCA 97

Vairy v Wyong Shire Council [2005] HCA 62; (2005) 223 CLR 422

Wyong Shire Council v Shirt [1980] HCA 12; (1980) 146 CLR 40

1 McLURE P: This is an appeal from the dismissal of the appellants' claims against the respondents for damage to wine grapes caused by smoke from a prescribed burn conducted in part of the Warren National Park in the south-west of Western Australia. The prescribed burn was carried out by officers of the Department of Conservation and Land Management (the Department) from late March to early April 2004. The prescribed burn was on 560 ha of land in the Warren National Park (referred to as DPHB8).

2 The first appellants were the registered owners of land on the north-east boundary of DPHB8. The second appellants leased portions of the land on which they (with one of the first appellants on its land) cultivated vines and grapes for wine production. The prescribed burn was conducted in the period between veraison (a grape developmental stage which commenced on 14 January 2004) and harvest (which was completed on 6 May 2004). Smoke from the prescribed burn tainted the grapes, causing a loss of $620,000.

3 The trial judge held that the respondents did not owe a general law duty of care to the appellants to avoid smoke damage to their grapes and even if they did, there had been no breach of duty under s 5B, s 5W(d) and s 5X of the Civil Liability Act 2002 (WA) (CLA). The trial judge did not consider or determine whether the respondents were liable in nuisance. Further, he did not determine the respondents' claim that they were exempt from liability under s 132 of the Conservation and Land Management Act 1984 (WA) (CALM Act).

4 In this appeal the appellants challenge the trial judge's findings in relation to duty of care and breach and contend the trial judge should also have found the respondents liable in nuisance. The respondents have filed a notice of contention seeking to uphold the trial judge's decision on the further ground that they are exempt from liability under s 132 of the CALM Act.

5 I differ from Pullin JA in relation to the issues that properly arise for determination in this appeal, the scope of the trial judge's factual findings and Pullin JA's conclusions on duty, breach and nuisance. He has concluded that the respondents, when conducting a prescribed burn on DPHB8 pursuant to its statutory power, owed a non-delegable duty to grape growers in the Donnelly District to ensure that reasonable care was taken by CALM employees to avoid the reasonably foreseeable risk of smoke damage to the grape growers' grapes.

6 Pullin JA has also concluded that the option of deferring the prescribed burn, season by season, until it was possible to burn outside the veraison to harvest period, was open on the evidence and that the respondents breached their duty by not deferring it. At the hearing of the appeal, the appellants' counsel repeatedly resisted invitations to widen the grounds of appeal to challenge the trial judge's finding in [488] that, practically speaking, a prescribed burn of DPHB8 was safe and effective only during the period when grapes were at a stage where smoke taint poses a not insignificant risk. For the reasons given below, I have concluded that counsel was correct to do so.

7 The statutory framework for the conduct of the prescribed burn is central to the determination of all the issues.

8 The Executive Director has two capacities. He is the Chief Executive Officer of the Department (s 36(3) of the CALM Act). He is also a body corporate bearing the name 'Executive Director of the Department of Conservation and Land Management' (s 38) in which capacity he is sued in this case.

9 The Department is a department of the Public Service of the State (s 32). Subject to the direction and control of the Minister, the functions of the Department are to, inter alia, manage land to which the CALM Act applies (s 33(1)(a)(i)).

The management of land referred to in subsection (1)(a)(i) and the associated forest produce, flora and fauna shall be carried out -

(a) where there is a management plan for the land, in accordance with that plan.

11 Land to which the CALM Act applies includes State forest and national parks (s 5(1)). It was common ground that DPHB8 was on land to which the CALM Act applies.

12 The Conservation Commission of Western Australia (Conservation Commission) is a body corporate established under the CALM Act (s 18). Section 19 sets out the functions of the Conservation Commission which include:

(a) to have vested in it State forest, timber reserves, national parks, conservation parks, nature reserves ... ;

...

(g) in relation to management plans for land vested, whether solely or jointly with an associated body, in the Conservation Commission -

(i) to develop guidelines for monitoring and assessing the implementation of the management plans by the Department;

...

(h) to advice the Minister on the application of the principles of ecologically sustainable forest management in the management of -

(i) State forests and timber reserves ... ;

...

(2) For the purposes of subsection (1)(h) the principles of ecologically sustainable forest management are -

(a) that the decision-making process should effectively integrate both long-term and short-term economic, environmental, social and equitable considerations;

...

(3) It is declared that the vesting in the Conservation Commission of State forest, timber reserves, national parks, conservation parks and nature reserves is only for the purposes of subsection ... [(1)(g), (h)] ... and does not otherwise limit the functions of the Department under section 33.

13 Part 5 div 1 of the CALM Act deals with management plans. The Conservation Commission is a 'controlling body' for the purposes of that division. Section 54 relevantly provides:

(1) A controlling body shall be responsible -

(a) for the preparation of proposed management plans; and

(b) the review of expiring plans and preparation of further management plans,

for all land which is vested in it whether solely or jointly with an associated body.

(2) ...

(3) Proposed management plans for any land shall be prepared -

(a) by -

(i) the controlling body for that land through the agency of the Department;

(ii) if the land is State forest or a timber reserve, the Conservation Commission through the agency of the Department in consultation with the Forest Products Commission.

14 The content of management plans is dealt with in s 55 which relevantly provides:

(1) A management plan for any land shall contain -

(a) a statement of the policies or guidelines proposed to be followed; and

(b) a summary of the operations proposed to be undertaken,

in respect of that land during a specified period, which shall not exceed 10 years.

15 The proposed management plan must be published in the Gazette (s 57). Provision is made for public submissions (s 58) and the management plan only comes into operation after being approved by the Minister (s 60). A Forest Management Plan for the period 2004 - 2013 (the Forest Management Plan) was approved by the Minister and came into operation on 1 January 2004. It replaced the Forest Management Plan for the period 1994 - 2003.

16 The Forest Management Plan deals with prescribed burning under the heading 'Ecosystem health and vitality'. The objectives and actions proposed are as follows:

Objective

The plan proposes the following Actions at the whole of forest and landscape scale for the purpose of seeking to use and respond to fire in a manner that:

• optimises the maintenance of forest ecosystem health and vitality;
• promotes the conservation of biodiversity;
• controls adverse impacts of fire on the social, cultural and economic values of land managed by the Department and adjoining land; and
• minimises the risk of smoke emanating from prescribed burns impacting on population centres and other sensitive areas.

Actions proposed

17.1 The Department will:

17.1.1 maintain a competent fire management, suppression and response capability;

17.1.2 prepare and maintain a fire management plan and smoke management guidelines;

17.1.3 undertake an annual prescribed burning programme in a manner that:

• is in accordance with the fire management plan;
• is in accordance with the smoke management guidelines;
• has regard to the Goals for Understorey Structural Diversity referred in Action 4.1; and
• considers any special vulnerability of fauna and flora known to exist in a particular area to burning in that area; and

17.1.4 consult with stakeholders and interested community members in a manner that seeks to develop community understanding of and support for, and enable constructive discussions and deliberations on, the planning and implementation of prescribed burning and other fire management programmes.

17 The trial judge found that the Department had prepared a 'master burn plan' which was the fire management plan for the Donnelly District (the fire management plan) for the purposes of cl 17.1.2 of the Forest Management Plan [157], [481]. There is no challenge to that finding. The trial judge also found that the fire management plan involves planning at four levels: (1) a three-year (six-season) indicative burning plan for the Donnelly District; (2) an annual indicative burning plan; (3) prescriptions for individual burns on the annual indicative burning plan; and (4) daily schedules in relation to the burning of particular areas on particular days [164]. If, for operational or other reasons, a burn in an annual programme is not able to be carried out in any year, it will generally be rolled over into the programme for the following year [167].

18 The burn prescription specifies the burn objectives, the weather and fuel conditions required to meet those objectives, the lighting sequences and patterns to be adopted, the burn coverage standards and smoke management requirements. It also includes a 'pre-burn' checklist which identifies potential risks and impacts, including smoke impacts.

19 The daily operational scheduling of prescribed burns is done via daily, State-wide telephone conferences in the morning (8.30 am) and evening (4.15 pm). Participants include Departmental district, regional and fire management services personnel. The daily burn programme is determined having regard to, inter alia, weather forecast and synoptic information provided by the Bureau of Meteorology, existing fire commitments, the level of resources available and smoke management. The approved programme is submitted to the Director of Regional Services where burns may be politically sensitive.

20 The Department had also complied with its duty to prepare smoke management guidelines. However, their content was not an issue at trial (or in the appeal).

21 In summary, the land the subject of DPHB8 is vested in the Conservation Commission who is responsible, with the Department, for developing a management plan. However, it is the duty of the Department to manage the land in accordance with the approved management plan. The Executive Director in his corporate capacity has no relevant role in the process.

22 What follows is the unchallenged background and factual findings of the trial judge. There are 926,604 ha of National Parks, State Forests, Conservation Reserves and unallocated Crown lands managed by the Department in the Warren Region [17]. The Warren Region is in the south-west of Western Australia and includes the towns of Manjimup, Pemberton and Northcliffe [18]. This region is, for Departmental purposes, referred to as 'the Donnelly District'.

23 There are approximately 60 vineyards around Manjimup and Pemberton. In many cases these vineyards abut land managed by the Department which is or will be the subject of a prescribed burning programme by the Department [19].

24 The Warren National Park has considerable environmental significance for the State, particularly with respect to its veteran karri forest. It is also a public asset of importance for recreational activities and tourism [20].

25 DPHB8 was located about 8 km south-west of Pemberton. The southern boundary of DPHB8 was the Old Vasse Road. To the north of DPHB8 there was private property including the appellants', and an area of State forest. The Warren National Park extended to the south. The area to the east and west of DPHB8 was surrounded by private property, with a number of dwellings close to its western boundary.

26 DPHB8 contained a substantial amount of karri forest. Karri forest is a dense, wet forest with deep litter which dries out very slowly compared with other forest types such as jarrah and wandoo [27]. The burn area for DPHB8 contained predominantly K1 and K2 understorey. That is the densest and wettest karri forest environment which dries out the most slowly and has the fewest number of days available for effective burning in any calendar year [32], [47].

27 The south-west forests of Western Australia are fire prone. The climate, characterised by cool wet winters and hot dry summers, provides the optimum conditions for the build up of litter on the forest floor [53]. The litter provides fuel for forest fires. When heavy fuel is combined with strong, hot and dry winds, uncontrollable high-intensity and damaging forest fires can result.

28 Fuel is the only factor affecting forest fire behaviour that humans can influence to reduce the speed and intensity of fire and make suppression easier. In all eucalypt forests the spread of fire depends on the debris and litter on the forest floor. Even under the worst conditions a fire cannot spread independently through the crowns of the trees. A crown fire in a eucalypt forest is always supported by intense fire-burning surface fuel. In essence, if there is no surface fuel there is no fire [56].

29 Fire suppression is a hazardous and dangerous activity to those undertaking it. Planned burning assists fire suppression by, inter alia, reducing the speed of growth of the fire from its ignition point, reducing the height of flames and the heat radiated from the flames, increasing the visual range in the forest and reducing the potential for spot fires [60].

30 For prescribed burning to be effective in reducing the impact of large fires under extreme weather conditions, a mosaic of recently burnt areas has to be established and maintained over large areas [61].

31 There are two primary sources of ignition of bush fires: lightning and humans. On average, about 35 bushfires are caused by lightning in the south-west forest every year [65]. Humans are responsible for around 90% of all fires in Western Australia, most of which are deliberately lit. Arson frequently occurs under severe fire weather conditions and arsonists often select the most difficult areas in which to operate [66].

32 Bushland in the south-west of Western Australia has three important characteristics in relation to its capacity to fuel a fire. They are: (1) the vegetation itself is highly flammable; (2) fine, flammable dry matter such as leaves, twigs and bark is constantly shed from living plants and accumulates; and (3) many tree species have stringy or fibrous bark which can be carried aloft as burning brands and embers in high winds, setting spot fires ahead of the main fire. Spotting and hop-overs are very common features of Western Australian forest fires and are nearly always associated with heavy and dry fuels [68].

33 The south-west fire season is in summer when hot, dry and windy conditions occur [73]. The south-west of Western Australia experiences, in effect, a form of drought every summer [74].

34 There are a number of consistent weather features which operate during the south-west fire season. Thunderstorms, which frequently generate lightning, occur regularly in the south-west region during the summer months. There is also the regular passage of a series of high pressure systems from west to east across the southern half of the continent, known as the West Coast Trough. These systems generate several-day cycles of increasingly hotter weather, with dry continental easterly winds backing into the north and north-west. Winds blowing from the north to north-west during summer and autumn are typically hot, gusty, dry and unstable. The transition from north-east to north-west winds often takes place abruptly and in the space of a few hours [75], [78].

35 There is a well recognised association in the south-west between northerly winds and dangerous fire conditions. Given that association and the fact that the transition of the wind from north-east to north-west often takes place abruptly and in the space of a few hours, the Department avoids commencing prescribed burns when such conditions are likely to occur before the burn is completed and mopped up [82].

36 The trial judge found that: (1) wildfires cannot be accepted as an uncontrolled variable in forest management as they represent a real risk to life, property, townships, plantations, young regrowth, tourism, recreation and nature conservation; and (2) the most effective and strategic way to reduce the risk of severe wildfire damage is by broad scale fuel reduction by prescribed burning during mild weather conditions [94] - [95]. The trial judge accepted the evidence of the experts called by the parties that:

(a) Prescribed burning is a necessary part of public land management to meet biodiversity, economic, silviculture, water and community protection objectives;

(b) Prescribed burning is the only effective way of reducing the potential impact of wildfires at a landscape level.

(c) Prescribed burning is complex and requires a high level of skill and planning.

(d) Prescribed burning operations are performed in a way in minimise environmental and economic damage.

(e) The Department has a detailed and thorough prescribed burn planning process.

(f) Prescribed burning prescriptions can be applied with some flexibility and discretion provided that approval to vary the prescription is received at the appropriate level. Professional judgment should be used to assess relevant risk mitigation or other operational factors and the prescribed burn should still meet the burn and operational management objectives [99].

37 In 1994, the Department determined that an annual prescribed burning programme of around 200,000 ha each year in the south-west forest regions was desirable to provide a reasonable level of fuel reduction and hence protection from wildfires across the land managed by the Department in that area. There was bipartisan political support in Western Australia for prescribed burning as the primary fire protection strategy for private and public assets and for rural communities in the south-west [123] - [124].

38 The Department was unable to achieve its 200,000 ha target in the years between 1997 and 2003 due to a combination of factors including dry seasons that were unfavourable for safe and effective burning, the risk of smoke being transported to the Perth metropolitan area, lack of available resources due to the occurrence of wildfires and planning and implementation difficulties [125]. During these years, a combined backlog of 452,837 ha of prescribed burns was accumulated. This added significantly to fuel loads across the south-west [127].

39 The years 2002 - 2003 was one of the worst seasons for bushfires in Western Australia since the early 1960s. In the Donnelly District alone there were 51 wild fires, 24 of which were caused by lightning [133].

40 After major bushfires in New South Wales, Victoria and the Australian Capital Territory in 2002 and 2003, a Select Committee of the House of Representatives of the Australian Parliament and the Council of Australian Governments conducted national inquiries relating to bushfires. The reports recommended prescribed burning programmes. The Western Australian Government strongly supported prescribed burning and provided additional funding for it in late 2003 [139].

41 The Department had developed a system for analysing the threat from, and planning appropriate responses to, wildfires (the Wildfire Threat Analysis). It provides a standardised, repeatable framework to analyse quantified data relating to the significant factors likely to contribute to the threat of wildfire [153]. The Wildfire Threat Analysis provides an objective comparison of wildfire threat between different areas with different risks. There is also a rating system devised for prescribed burning which uses the fire protection and other management values referred to in the Wildfire Threat Analysis. The rating system is used to provide a guide for burning priorities and is used to ensure that the highest priority areas are burnt. Under the rating system the strategic value of a burn is allocated points between zero and 60. DPHB8 was given the highest strategic value of 60 points [155].

42 There are also tactical benefits derived from burning areas in an integrated scheme which are taken into account in the planning of burns by the Department [156].

43 To assist in predicting burning opportunities in the karri forest, the Department uses a publication developed by its officers entitled 'The Forest Fire Behaviour Tables for Western Australia' (known as the 'Red Book') [329]. Based on the evidence of the experts, the trial judge found that the Red Book was the best predictive tool for determining suitable prescribed burning conditions in karri forests.

44 There are a number of variables in the identification of prescribed burning opportunities including the 'surface moisture content', 'profile moisture content' of all litter, 'fire danger index', 'soil dryness index' and weather conditions.

45 The surface moisture content, which relates to the moisture content of the surface litter and other near surface fuels, must be within the range of 10% to 18% to ensure good ignition and mild to moderate fire behaviour [334].

46 The profile moisture content of karri litter fuels, which are relatively deep, must be between 25% to 60%. The proportion of a fuel bed that is available to burn (known as the 'available fuel factor') needs to be between 30% to 70% for a fuel reduction burn to be safe and effective [338]. That proportion requires the surface moisture content and profile moisture content to be within the specified ranges.

47 There are only a limited number of days each year when the required combination of surface moisture content and profile moisture content occurs in conjunction with the mild conditions (wind, air temperature, relative humidity, atmospheric stability) required to conduct an effective and safe fuel-reduction burn [339].

48 Wind speeds recorded in the open (or above the tree canopy) should not exceed 20 km per hour. Lower wind speeds are required if surface fuels are dry and where a high proportion of the fuel bed is available to burn [349]. Further, the wind direction is an important limiting factor as it affects the direction of the head fire and the embers that can 'spot over' a burn boundary [351]. The fire danger index is calculated from the surface moisture content and the wind speed for each forest type.

49 The acceptable wind direction is also dictated by the location of adjacent heavy and flammable fuels. DPHB8 was located immediately north of very old heavy karri fuels in the Warren National Park. A burn prescription for DPHB8 on north to north-west winds would be inappropriate. The safest wind directions for a burn of the area of DPHB8 are those that blow from the south, albeit with an easterly component [353] - [354].

50 Further, the stable weather conditions that are normally suitable for safe fuel reduction burning in the south-west forests are frequently the same that lead to smoke being blown by southerly winds into Perth, Bunbury and Mandurah. Smoke can be trapped below a blanket of warm air, called an inversion. Smoke can also be trapped under the night-time inversion that often develops in the south-west during the cool nights in the spring and autumn burning periods [356].

51 The Department manages smoke from prescribed burns, primarily with a view to preventing smoke and haze from settling on Perth and major regional centres. Other locations sensitive to smoke and ash, such as harnessed water bodies and local towns and communities, are also taken into consideration in the management of smoke from prescribed burns [357].

52 The soil dryness index is a numerical value that reflects the dryness of soil, deep forest litter, logs and branches. The Red Book contains a table of recommended soil dryness index limits for fire control operations in the forest. Burning outside these recommended limits increases the risk of fire escape and the cost of control and mop up of the burn. The dense karri fuel types, K1 and K2, will usually not be sufficiently dry until the soil dryness index exceeds 800 [362]. The burn prescription for DPHB8 prescribed a soil dryness index of at least 800. That figure was first reached in the spring/summer of 2003/2004 on 6 January 2004 [364].

53 DPHB8 had last been burnt in 1988 - 1989. At the time of the prescribed burn it was carrying fuel loads of 73 - 93 tonnes per hectare when the limit at which most wildfires can be contained in karri forests is 15 - 19 tonnes per hectare [267].

54 DPHB8 was put on the three-year indicative burn plan in the 1998 - 1999 fire season based on Wildfire Threat Analysis principles, fuel ages and the time since it was last burnt. DPHB8 was a high priority burn and was strategically important to protect the life of residents and visitors in the area, property on adjoining private property, departmental infrastructure in the Warren National Park and regrowth of the forest south of the Warren National Park. The Warren National Park south of the burn area had high fuel levels with some areas more than 25 years' old and there was a significant risk that a fire escape across the southern boundary of DPHB8 could result in an uncontrollable wildfire.

55 In 2000 the DPHB8 burn prescription was approved for entry into the annual burn programme. The initial burn prescription was checked, reviewed and approved for implementation. The objectives of the prescribed burn were:

(a) to provide protection against wildfire damage to adjoining private property, the mature forest within the Warren National Park, park facilities and park visitors by the creation of fuel reduced areas; and

(b) to protect and maintain biological diversity processes and ecological values within the burn area by the application of a low intensity, slow moving prescribed burn that will provide a mosaic of burnt (70% - 90%) and unburnt (10% - 30%) patches.

56 The core lighting strategy of the burn prescription stated 'winds to be from a southerly direction' [279]. There were no opportunities to safely undertake the burn in the 2002 - 2003 season as Western Australia experienced a severe fire season across the State. DPHB8 was carried into the 2003 - 2004 burn programme with increased fuel loads which raised its priority for burning [284].

57 The DPHB8 prescribed burn required two days to light up. Several days thereafter were allowed for mopping up and patrolling the boundaries [87]. The burn of the edges of the area was done by hand. The burning of the remaining bulk of the area is called 'core ignition'. It is important for the edging burn to be deep enough so that when the core ignition is lit, the fire remains in the middle of the burn and does not run out to the boundaries. In the case of DPHB8, an edging depth of least 100 m was required by the burn prescription [90].

58 Expert evidence was adduced in relation to the effect of smoke on grapes. The trial judge accepted the agreed expert evidence that there was awareness of the risk of smoke contamination of wine grapes at the time of the prescribed burn but the level of knowledge was considerably less than that available at trial [265].

59 Based on the level of expert knowledge at trial, the trial judge concluded that:

(a) grapes are contaminated by smoke coming in contact with the vines, and the berries directly absorbing smoke compounds, or other parts of the vine absorbing the smoke compounds and the translocation of the smoke compounds to the berries via the phloem of the grapevine;

(b) it is likely that any smoke exposure, even of a low density or for a short period, has the potential to contribute to the uptake of smoke compounds in the berries and other parts of the vines;

(c) the risk of uptake of smoke compounds into the grapes is likely to be at its highest for seven days post-veraison to harvest, but the risk is not insignificant in the preceding period between when the berries are pea-size to three days post-veraison, and there remains a risk, albeit a low risk, in the vine-dormancy and early shoot-emergence period; and

(d) whilst it is likely that any event of smoke exposure has the potential to contribute to the uptake of smoke compounds, the level of contribution will be dependent on, inter alia, undefined environmental or physiological restraints [479], [433].

60 The appellants' vineyard manager (Mr Pearse) had no knowledge that grapes might be affected by smoke until after the 2001 vintage [192]. In early 2002 Mr Pearse informed a CALM officer that smoke from an aerial burn (obviously not DPHB8) had affected the previous year's grape crop. In December 2003, Mr Pearse received notice of prescribed burn DPHB8 and advised CALM officers of his concerns about the prospect of smoke tainting. In December 2003 and January 2004 the Department received requests from other grape growers in the Pemberton area to defer other prescribed burns (DP33 and DP14) until after harvest [215], [223], [229].

61 On 3 February 2004, the first respondent signed a Contentious Issue Briefing Note which he submitted to the Minister for the Environment. The Briefing Note included the following:

The Department's position is that it will consult neighbours but the commencement and carrying out of prescribed burns will not be delayed at the request of individual wine grape growers. All prescribed burns will be commenced and carried out when the field conditions are suitable for the burn and resources are available.

62 On 7 February 2004, the Minister for the Environment approved the Department's approach in the Briefing Note. In the meantime, the appellants' solicitors had written to the Department advising that the appellants would hold the Department liable if the burn of DPHB8 proceeded and their grapes were damaged [245].

63 The four-day forecast on 30 March 2004 indicated that weather conditions would be suitable for the burn of DPHB8. The fire behaviour parameters (surface moisture content, profile moisture content and soil dryness index) were also recorded as being consistent with the burn prescription [419]. Moreover, the burn prescription was amended so as to minimise its smoke impact on the appellants' vineyards. The amendment related to the wind direction on which the core ignition was to be undertaken. That required the Department to increase its resources on the western boundary. There was in fact a hop-over on the western boundary that had to be dealt with [418].

64 The appellants contended at trial (but not in the appeal) that the burn of DPHB8 could have been delayed or rolled over, claiming the first respondent's evidence was that the burn was neither necessary nor urgent. In response to that submission the trial judge said:

In my view, the words 'necessary' and 'urgent' are capable of creating a misleading impression, in this context, in that they are apt to convey the notion that prescribed burning is done in response to ad hoc dangers as they arise from time to time, rather than as an integrated strategy designed to deal with the systemic risk of wildfire inherent in the landscape and environment of the State generally, and of the south-west in particular. It is correct to say that there was no evidence that absent a prescribed burn on 31 March 2004, there was an immediate and substantial risk that a wildfire would break out in the area of DPHB8. To that extent, the prescribed burn of DPHB8 might, on one view of it, conceivably be described as being neither 'necessary' nor 'urgent' in early 2004. Nevertheless, that characterisation imports an artificial and narrow focus which obscures the broader context in which the large-scale programme of prescribed burning is designed and implemented in Western Australia generally, and in the south-west of the State in particular [408].

65 Experts called on behalf of the appellants, Dr Tolhurst and Mr Muller, gave evidence of the opportunities for burning DPHB8. The trial judge rejected much of Dr Tolhurst's evidence. However, he accepted Dr Tolhurst's evidence that it was not possible to conduct DPHB8 without putting some smoke over the appellants' vineyard at some time during the prescribed burn.

66 The trial judge accepted the evidence of the appellants' expert Mr Muller who had considered the window of opportunity for prescribed burning in seven fire seasons between November 2000 and May 2007 [374]. In relation to those seven seasons, Mr Muller's conclusions in his report include the following:

On average there are only between 1 (for Karri 1 & 2) and 7 (for Southern Jarrah) suitable burning days outside the veraison to harvest period. Even if there were no other constraints and burning could be conducted on each of these days, this is fewer days than the number of burns required to effectively restrict the spread of major summer wildfires.

It is therefore not possible to maintain an effective fuel reduction burning programme if burning is restricted to outside the veraison to harvest period.

67 In cross-examination, Mr Muller agreed that: DPHB8 was a necessary part of the prescribed burning programme; it was inevitable that prescribed burning would cause smoke on vineyards in Pemberton or in the Pemberton region; it is not possible to have an effective prescribed burning programme in the Pemberton region if you can burn only outside the veraison to harvest period; reasonable steps were taken to minimise smoke over the vineyards when the burn of DPHB8 was conducted; there were no other reasonable steps that could have been taken short of deferring the burn; and that a prudent fire manager would have taken advantage of the window of opportunity on 31 March 2004.

68 The trial judge found that 'there are approximately 60 vineyards which are adjacent or in close proximity to the areas managed by the Department, and which are also susceptible to smoke taint' [444]. He also accepted that the Department has no control over the way smoke will drift after a fire is started. Once a burn is commenced, the smoke will travel in whatever direction the wind, in combination with the relevant atmospherics, will take it [477].

69 Before leaving the facts, I propose to consider whether the trial judge erred in concluding that practically speaking, a prescribed burn of DPHB8 was safe and effective only during the period when the grapes were at a stage where smoke taint posed a not insignificant risk [488]. It needs to be understood that the trial judge did not confine the risk period to that between veraison and harvest. The period of 'not insignificant risk' (to use the statutory language) included the preceding period when the berries are pea-size to three days post-veraison.

70 Even if that period is excluded, the finding in [488] is in accordance with Mr Muller's evidence, accepted by the trial judge, that in the seven-year period between 2000 and 2007, there was, on average, one day in each fire season that was suitable for burning a karri forest with K1 and K2 understorey. The prescribed burn of DPHB8 required two days just for the purpose of lighting up.

The trial judge's findings on duty and the scope of the challenge

71 The trial judge accepted the reasoning of Buss JA in Department of Housing and Works v Smith [No 2] [2010] WASCA 25 [77] that s 5B of the CLA relates to a breach of a duty of care and does not modify or supplant the common law principles which determine whether a duty of care exists or not. In any event, the parties at trial conducted the case on the basis that the issue of duty of care was governed by the general law.

72 The trial judge noted that on one view of the appellants' case, it involved the proposition that 'the Department should not have performed its statutory obligation to manage the land by the carrying out of a prescribed burn in accordance with its fire management plan pursuant to the Forest Management Plan ... in order to avoid the risk of smoke taint to [the appellants'] grapes'. He said:

Insofar as that is the nature of [the appellants'] case, it is, in my view, inconsistent with the statutory functions of the Department and no duty of care arises under the general law [481].

73 Alternatively, if the appellants' case was characterised as a claim that 'the Department had a common law duty ... to exercise care to avoid the risk of smoke taint to grapes, to which its statutory duty to carry out prescribed burning so as to serve the overall objectives prescribed by the Forest Management Plan is subservient, the common law duty would also ... be inconsistent with the statutory scheme' [482].

74 He also concluded that a common law duty of care to 'take into account relevant considerations and give proper consideration to the risk of smoke taint to [the appellants'] grapes in planning and implementing prescribed burning so as to minimise the effect of smoke on "sensitive areas"' would tend to distort, by skewing, the focus of the statutory decision-making process, and distort the performance of the Department's statutory functions [484] - [485].

75 For those reasons, he concluded that the respondents did not come under a duty of care to the appellants to avoid smoke taint to grapes when the Department was undertaking the planning and implementation of prescribed burning.

76 He further concluded that the imposition of a duty of care would not be regarded as reasonable in the circumstances. After referring to the limited opportunities for burning DPHB8 and the periods during which grapes were at risk from smoke taint, the trial judge continued:

Accordingly, practically speaking, the time when it is safe and effective to carry out prescribed burning in karri forest with K1 and K2 understorey is the time when the grapes are at stages of development where smoke taint poses a not insignificant risk. A duty to exercise reasonable care to avoid the risk of smoke taint to [the appellants'] grapes in planning and implementing a prescribed burn would involve the imposition of a legal obligation which was, in practical terms, incapable of being discharged.

Also, given the risk of smoke taint to grapes, the distance over which smoke may be carried on the wind, and the existence of 60 vineyards in the area in question, the existence of a common law duty is likely to involve competing duties to vignerons within the class. A wind forecast to take smoke away from one vineyard may well take it on to another. The point is illustrated by the vineyards around the prescribed burn 'Big Brook' (exhibit 33B), which has vineyards to the north and north-west, to the west, to the south, and to the east and north-east [488] - [489].

77 The appellants say the trial judge erred in failing to find a duty of care in the following terms:

1(a) The First Respondent in caring for and managing Crown lands, including State forest, owed a duty of care to neighbouring land owners (including the Appellants) when bringing onto such land fire, for an unnatural or dangerous use, not to allow fire, smoke or ash from that fire to escape causing foreseeable damage to that neighbour's land;

(b) The Second Respondent ... being a land owner who brought onto its land fire for an unnatural or dangerous use, owed a duty of care to neighbouring land owners (including the Appellants) not to allow fire, smoke or ash from that fire to escape causing foreseeable damage to that neighbour's land.

78 The remaining grounds of appeal in relation to duty of care are as follows:

1. In coming to the conclusion that no duty of care existed the learned trial judge erred in law in finding that:

(a) there is an inconsistency between the First Respondent's statutory duties under the [CALM Act] and a duty of care to the Appellants;

(b) lighting fires in a State forest and/or prescribed burning is a statutory obligation under the Act; and

(c) being required to observe or be bound by a duty of care to the Appellants would prevent, preclude or inhibit the First Respondent from carrying out its statutory duties under the Act.

1. The learned trial judge should have found that management plans made under the Act and approved by the responsible Minister were incapable in law of creating legal immunities ...
2. In coming to the conclusion that no duty of care existed, the learned trial judge further erred ... in not finding that starting fires or burning off in the way the Respondents did was an unnatural or dangerous use ...

1. The learned trial judge erred in law and fact in coming to the conclusion ... that the existence of a duty of care to the Appellant was or was likely to involve competing duties to other land owners;

(b) [t]here is no legal principle that a duty of care owed to a geographical neighbour can be ignored or not complied with or cease to be imposed because a similar duty is owed to another geographical neighbour;

(c) [t]he learned trial judge should have found that the Respondents owed a duty to prevent foreseeable damage to all close geographical neighbours.

79 There are echoes in the appellants' statement of the duty of care of the former rule of strict liability in Rylands v Fletcher [1868] UKHL 1; (1868) LR 3 HL 330, both in the terminology employed (unnatural or dangerous use) and in the absence of any reference to a requirement to exercise reasonable care. This links with the appellants' ground 5 relating to the standard of care which they say is a degree of diligence by the respondents so as to amount to a guarantee of safety for the appellants.

80 The appellants were forced to this extreme formulation of the duty and standard of care because of the absence of a challenge to the finding that the respondents had no practical alternative but to burn during the period when there was a not insignificant risk of smoke tainting the appellants' grapes.

81 In substance, the appellants contend the trial judge should have taken a two-step approach to determining the respondents' duty of care. The first step is to examine whether the relationship between the parties gave rise to a well-known, well-established and accepted duty of care at common law (to which they answer yes). The second step is to consider whether the CALM Act excluded the need for the respondents to comply with the common law duty (to which they answer no).

82 The appellants place significant reliance on Burnie Port Authority v General Jones Pty Ltd [1994] HCA 13; (1994) 179 CLR 520. In that case the owner of a building retained an independent contractor to do work on extensions to the building. The work involved welding activities in close proximity to cardboard cartons containing an insulating material which burnt fiercely if brought into sustained contact with flame. Due to the contractor's negligence, sparks or molten metal fell on the containers and caused the insulating material to burn. The ensuing fire spread to an area of the building occupied by a licensee and caused damage to its stock.

83 The High Court held that for the purposes of the common law of Australia, the rule in Rylands v Fletcher has been absorbed by the principles of negligence, under which a person who takes advantage of the control of premises to introduce a dangerous substance, to carry on a dangerous activity or to allow another to do one of those things, owes a duty of reasonable care to avoid a reasonably foreseeable risk of injury or damage to the person or property of another (556 - 557). Although the standard of care is that which is reasonable in the circumstances, in the case of such substances or activities a reasonably prudent person would exercise a higher degree of care and, depending upon the magnitude of the danger, the standard of 'reasonable care' may involve 'a degree of diligence so stringent as to amount practically to a guarantee of safety' (554).

84 It is immediately apparent that Burnie Port Authority does not provide any authority for the strict duty of care for which the appellants contend. However, the principles in that case relating to duty and breach do not apply for additional reasons.

85 First, this is a claim about the escape of smoke not fire. Fire is inherently and unequivocally dangerous whereas smoke is not.

86 Secondly, the fact that the Department was in control of the land on which the prescribed burn was conducted and the appellants were the owners and occupiers of adjoining land, does not sufficiently describe the relationship between the parties. It ignores the statutory framework and other relevant contextual considerations in the assessment of the existence and scope of any duty of care. This case is more akin to the situation in Miller v Miller [2011] HCA 9; (2011) 242 CLR 446 [62] - [65] than that in Kuhl v Zurich Financial Services Australia Ltd [2011] HCA 11; (2011) 243 CLR 361 where the answer given by the majority as to whether a duty of care existed depended solely upon ticking boxes on questions of foreseeability [79].

87 Thus the two-step approach of the appellants is misconceived. It is predicated on the erroneous assumptions that first, this is a case where the existence of a duty of care is well-established and well understood and secondly, that the only question is whether the common law duty has been excluded by the statutory scheme.

88 This is not a case where the existence or scope of a duty is well-established or well understood except at a high level of generality which is of no practical assistance. A duty formulated at too high a level of abstraction may provide an inadequate legal mean by which to determine the issue in a particular case. It will be too abstract if it is divorced from the facts said to enliven the duty: Cole v South Tweed Heads Rugby League Football Club Ltd [2004] HCA 29; (2004) 217 CLR 469 [56], [81] (Gummow & Hayne JJ). On the other hand, it is wrong to formulate the duty with such particularity as to in effect circumvent the requirement of reasonableness at the breach stage of the analysis: Graham Barclay Oysters Pty Ltd v Ryan [2002] HCA 54; (2002) 211 CLR 540 [191] - [192] (Gummow & Hayne JJ).

89 When in doubt about where to pitch the duty, an alternative approach is to ask whether the type of damage suffered, caused by the particular want of care alleged against the defendant, resulted from the breach of a duty which the defendant owed the plaintiff. It is said this approach may reveal more readily the scope of the duty from which the plaintiff's allegation of breach and damage must depend: Modbury Triangle Shopping Centre Pty Ltd v Anzil (2000) 205 CLR 254 [105]. The trial and appeal were conducted on the basis that the appellants suffered property damage, not pure economic loss. I will proceed on that assumption.

90 The existence and scope of a duty of care owed by a public body or officer (defined in s 5U of the CLA to include the respondents and the Department) is not governed solely by the common law. Section 5W of the CLA states principles that apply to both duty and breach. However, it is convenient to commence with the common law.

91 There is no single unifying principle for liability in negligence of public authorities: Pyrenees Shire Council v Day [1998] HCA 3; (1998) 192 CLR 330 [189]. The law has been described as remarkably confused: Aronson MI, 'Government Liability in Negligence' [2008] MelbULawRw 2; (2008) 32 Melbourne University Law Review 44, 46. So it is. Aronson notes a movement away from immunity from duty, at least in relation to 'policy' decisions, towards the more flexible breach stage which focuses attention on the reasonableness of a particular act or omission: Pyrenees Shire Council [182] - [183]; Brodie v Singleton Shire Council [2001] HCA 29; (2001) 206 CLR 512 [106], [150] - [151].

92 But even at common law, the factors relevant to the existence and scope of a duty of care can differ when the putative tortfeasor is the government (federal, state or local): Graham Barclay [12] (Gleeson CJ). That is primarily because the statutory context in which the government is obliged or empowered to act is instrumental in shaping the contours of the duty of care and the specific acts or omissions (content) falling within the scope of the duty. See Drexel London (a firm) v Gove (Blackman) [2009] WASCA 181 [262] - [268].

93 Prima facie, when statutory duties or powers are conferred they must be exercised with reasonable care, so that if those who exercise them could by reasonable precaution have prevented an injury which has been occasioned, and was likely to be occasioned, by their exercise, damages for negligence may be recovered: Sutherland Shire Council v Heyman [1985] HCA 41; (1985) 157 CLR 424, 458; Pyrenees Shire Council [177]; Stuart v Kirkland-Veenstra [2009] HCA 15; (2009) 237 CLR 215 [117].

94 The respondents conceded (correctly in my view) that under the general law, the Department would be liable for damage caused by the escape of fire from a prescribed burn on property under its control which is attributable to the negligent exercise of its statutory powers and duties. However, we are only here concerned with smoke damage from a fire that for all intents and purposes remained within the intended boundaries of a prescribed burn. Moreover, it was common cause that DPHB8 was appropriately included on the prescribed burning programme and that there was no reasonable alternative method of achieving the statutory objectives.

95 The prima facie statement of duty is subject to limitations arising from the principle of coherence. There will be no duty at common law to the extent that it is incompatible with other duties, statutory or otherwise, imposed on a defendant. Incompatibility includes, but is not confined to, situations where a statute expressly or impliedly excludes a common law duty. This is explained by the High Court in Sullivan v Moody (2001) 207 CLR 562. The court said:

The circumstance that a defendant owes a duty of care to a third party, or is subject to statutory obligations which constrain the manner in which powers or discretions may be exercised, does not of itself rule out the possibility that a duty of care is owed to a plaintiff. People may be subject to a number of duties, at least provided they are not irreconcilable ... But if a suggested duty of care would give rise to inconsistent obligations, that would ordinarily be a reason for denying that the duty exists. Similarly, when public authorities, or their officers, are charged with the responsibility of ... exercising powers, in the public interest, or in the interests of a specified class of persons, the law would not ordinarily subject them to a duty to have regard to the interests of another class of persons where that would impose upon them conflicting claims or obligations [60].

96 The question is whether a duty of the kind for which the appellants contend can rationally be related to the functions, powers and responsibilities of the various persons and authorities who are alleged to owe that duty: Sullivan v Moody [55]; Tame v The State of New South Wales [2002] HCA 35; (2002) 211 CLR 317 [123], [231]. Thus, a duty will not arise if it may undermine the effectiveness of the duties imposed by the statute or if it could distort the performance of statutory functions: Graham Barclay [78]; Crimmins v Stevedoring Industry Finance Committee [1999] HCA 59; (1999) 200 CLR 1 [216], [292]; Hunter Area Health Service v Presland [2005] NSWCA 33; (2005) 63 NSWLR 22 [21].

97 At common law, the distinction between a statutory power and a statutory duty, generally speaking, has limited relevance to tortious liability arising out of the performance or non-performance of statutory functions: Sutherland Shire Council (457) (Mason J). Mason J continued:

When a statute sets up a public authority, the statute prescribes its functions so as to arm it with appropriate powers for the attainment of certain objects in the public interest. The authority is thereby given a capacity which it would otherwise lack, rather than a legal immunity in relation to what it does, though a grant of power may have this effect when the infliction of damage on others is the inevitable result of its exercise. In framing such a statute it is inconvenient to describe the intended activities of the authority in terms of a series of positive duties. It is preferable to express those activities as functions or powers so that the authority is free to make policy-making decisions and discretionary judgments with a view to attaining the statutory objects. Decisions and judgments of this kind will be involved as a preliminary to exercising, or declining to exercise, a power and, subsequently, in determining how it is to be exercised. Viewed in this light statutory powers are not in general mere powers which the authority has an option to exercise or not according to its unfettered choice. They are powers conferred for the purpose of attaining the statutory objects ... (457).

98 Against that background I turn to the regulatory framework, the source of which is the CALM Act, the Forest Management Plan and the fire management plan. The Department is under a general statutory duty to conduct prescribed burns in the south-west of Western Australia: Bridgetown/Greenbushes Friends of the Forest Inc v Executive Director of the Department of Conservation and Land Management (1997) 18 WAR 126. In particular, the Department is under a statutory duty to manage land to which the CALM Act applies (which includes DPHB8) in accordance with the Forest Management Plan: s 33. The Department complied with its duty under cl 17.1.2 of the Forest Management Plan to prepare a fire management plan and smoke management guidelines, and its duty under cl 17.1.3 to undertake an annual prescribed burning programme that was in accordance with the fire management plan and smoke management guidelines.

99 Pursuant to the exercise of its duties and powers, the Department placed DPHB8 on the annual prescribed burning programme for 2003/2004. However, inclusion on the annual prescribed burning programme does not determine when or how any particular prescribed burn is to be carried out. The decision to burn can only reasonably be made shortly before it is carried out and then only when all of the many conditions necessary for a safe and effective burn come into alignment.

100 One of the primary purposes of a prescribed burn in the south-west of this State is to materially reduce the destructive impact of wildfires at a landscape level. Wildfires in the south-west are a real and present danger, particularly in summer, and pose a real risk to life and property. On any view, the destructive potential of a wildfire in relation to life and property is multiple orders of magnitude higher than the destructive potential of smoke alone.

101 There can be no prescribed burn without smoke. Further, the Department does not have control over all the variables that can impact on the amount, intensity, duration and direction of smoke from a prescribed burn. This is confirmed by the appellants in their ground of appeal 6(ii) which relevantly provides:

Both Respondents knew that no sensible or reasonable precautions could be taken (once the burning off operations commenced) to prevent damage to the Appellants because:

(a) the weather in the locality of the land in question at the time of the burn was and is unpredictable ...

(b) the wind direction and speed in the locality of the land in question at the time of the burn was and is unpredictable.

102 It is clear from the statutory language and its scope and purpose that the objective of minimising the risk of smoke from a prescribed burn impacting on sensitive areas is subsidiary to the primary objects of the power. The Forest Management Plan uses the term 'minimise' rather than avoid. By 'subsidiary' it is meant that where there is a conflict between the furtherance of a primary purpose of the power and minimising the risk of smoke impact, the latter must yield.

103 Further, it is of particular significance that the Department exercises its powers in relation to prescribed burning for the benefit of the south-west community as a whole. Different classes of interested parties and even individuals within classes will have interests which are in conflict. For example, minimising the risk of smoke over the appellants' vineyards increased the risk of fire escaping over the western boundary of DPHB8 where there are residential dwellings.

104 The common law will not impose a duty on the Department that is incompatible with the primary purposes of its statutory functions (that is, its duties and powers) and, when the power is to be exercised for the benefit of the south-west community as a whole, where persons potentially affected by the Department's decisions have competing and conflicting interests.

105 It follows that the strict duty contended for by the appellants is simply not open. On the appellants' statement of the duty, the alleged breach is in effect the conduct of any prescribed burn on DPHB8, and on any other land under the control of the Department, from which smoke could travel to the appellants' vineyard. Smoke can travel long distances. As I sit writing this judgment in the centre of Perth, the City is and has for the past few days been swathed in thick smoke from a bushfire caused by lightning in the Warren region near Northcliffe, some 350 km to the south. The appellants' formulation of the duty is directly inconsistent with the Department's statutory functions.

106 I turn now to Pullin JA's formulation of the duty. It incorporates a statement that it is non-delegable which I address below when considering s 132 of the CALM Act. The question is whether the Department owes a duty to grape growers in the Donnelly District to take reasonable care to avoid the reasonably foreseeable risk of smoke damage to the grape growers' grapes. The answer is no for a number of reasons. First, grape growers as a class form a subset of a much wider class, or group of classes, all of which are potentially affected by the Department's exercise of its statutory functions in connection with a single prescribed burn, many of which will have different and often conflicting interests to grape growers. Indeed, a single prescribed burn may also generate conflicts of interest within the class of grape growers. The best interests of a vigneron whose grapes are not at risk of smoke taint from a particular prescribed burn may be in reducing the risk of destruction of its income producing assets from an uncontrollable wildfire.

107 Secondly, the duty is to avoid the risk of smoke damage to grapes. The only way the risk can be avoided is to not carry out a prescribed burn anywhere in the Warren region when there is a not insignificant risk of smoke damage to the grapes on one or more of the 60 vineyards in the region. That outcome is incompatible with the primary purposes of the Department's powers and duties and with its duty to perform its statutory functions in the best interests of the community as a whole.

108 It is incompatible even if the trial judge erred in finding that practically speaking, the only time it is safe and effective to carry out prescribed burning in karri forest with K1 and K2 understorey is when the grapes are at stages of development where smoke taint poses a not insignificant risk. The effectiveness of prescribed burning as a fire mitigation tool depends upon an integrated strategic approach on a whole of landscape level.

109 In any event, I have concluded that the finding was well open on the evidence. That being so, the practical effect of the duty formulated by Pullin JA is to prevent any prescribed burning of karri forest with K1 and K2 understorey. That is directly inconsistent with the Department's statutory functions.

110 In order to accommodate the complexities created by the regulatory framework, I would formulate the Department's duty at an unusually high level of generality along the following lines. Subject to s 5X of the CLA and to the proper exercise of its statutory functions relating to prescribed burning, the Department in the performance of those functions has a duty to exercise reasonable care to avoid or minimise the risk of harm to persons and property. I would then apply the Hayne J test in Modbury Triangle and conclude that the alleged negligent acts do not fall within the scope of the duty.

111 I would dismiss grounds of appeal 1, 2, 3, 4, 5 and 12.

112 The thrust of the appellants' submissions is that the trial judge should have found that the performance of the statutory function itself (conducting a prescribed burn on DPHB8) was the relevant negligent act. That is, it can never be reasonable to carry out a prescribed burn in the Warren region if there is a not insignificant risk of smoke damage to grapes grown for commercial purposes. This contention reveals why the legal analysis can only appropriately be resolved at the duty stage. It is not the function of a court to rule on the reasonableness of statutory functions that the legislative arm of government has bestowed on the Department. In this case, 'social utility' for the purpose of s 5B(2)(d) of the CLA is not a matter on which the court is free to form and act upon its own personal assessment of the reasonableness of the statutory objectives and purposes.

113 Pullin JA says it was unreasonable not to defer the prescribed burn because it had not been established that it was 'impossible to ever burn' DPHB8. That reasonableness analysis gives primacy to the need to avoid smoke damage to grapes and ignores all other competing and conflicting interests. It is a flawed approach which flows from the formulation of the duty. Moreover, and in any event, the conclusion is inconsistent with the unchallenged findings of the trial judge that practically speaking it was impossible to conduct a safe and effective prescribed burn in karri forest with K1 and K2 understorey without creating a not insignificant risk of smoke tainting of grapes, and that DPHB8 was part of an integrated strategy designed to deal with the systemic risk of wildfire inherent in the landscape as a whole. It is wrong to focus on DPHB8 in isolation.

114 Having regard to the nature of the alleged negligent breach relied on by the appellants, it is unnecessary to address their grounds of appeal relating to s 5W(d) and s 5X of the CLA. It is sufficient for present purposes to note that for practical purposes s 5X operates so as to significantly alter the otherwise applicable standard of care at common law. The statutory standard is the Wednesbury test of reasonableness (Associated Provincial Picture Houses Ltd v Wednesbury Corporation [1947] EWCA Civ 1; [1948] 1 KB 223, 230). It is wrong to equate that standard with the general law standard of care in negligence. There is no arguable foundation for a claim that the decision to proceed with the prescribed burn in this case was so unreasonable that no reasonable public body or officer in the respondents' position could have made it.

115 I agree with Pullin JA that the appellants did not unequivocally abandon their claim in nuisance which was open on the pleadings.

116 In order to determine whether the CLA applies to the appellants' nuisance claim, it is necessary to examine the common law.

117 Unless and until the High Court determines that the tort of nuisance, like the principle in Ryland v Fletcher, is subsumed in the tort of negligence, this court must proceed on the basis that nuisance is a separate cause of action.

118 Nuisance protects a claimant's interest in the beneficial use of land. It is not confined to the actual use of the soil but extends to the pleasure, comfort and enjoyment which a person normally derives from occupancy of land. Thus, nuisance covers physical damage to property and non-physical damage. To constitute a nuisance, the interference must be unreasonable. In making that judgment, regard is had to a variety of factors including: the nature and extent of the harm or interference; the social or public interest value in the defendant's activity; the hypersensitivity (if any) of the user or use of the claimant's land; the nature of established uses in the locality (eg residential, industrial, rural); whether all reasonable precautions were taken to minimise any interference; and the type of damage suffered.

119 This exercise involves weighing the respective rights of the parties in the use of their land to make a value judgment as to whether the interference is unreasonable. Although the 'fault' of the defendant may be a relevant consideration in an assessment of whether the interference with the claimant's enjoyment of land is unreasonable, the duty not to expose one's neighbours to nuisance is not necessarily discharged by the exercise of reasonable care. Liability in nuisance is strict. Once a prima facie case has been established, it is for the defendant to prove its defence.

120 There is a compelling case that, even though smoke from the prescribed burn of DPHB8 caused property damage, it did not constitute an unreasonable interference with the appellants' land. Prescribed burning has been a feature of the south-west forests for over 80 years, long before the arrival of vineyards in the area; the evidence established that it is in the public interest of the community as a whole to carry out prescribed burning in the south-west forests in order to (inter alia) reduce the risk to persons and property from wildfires, which are commonplace in the region; the reduction in risk from wildfires is also in the interests of persons who have commercial vineyards on their land; smoke is the inevitable and unavoidable consequence of prescribed burning (and wildfires); the potential damage to property from wildfire is far greater than that caused by smoke; it was practically impossible to conduct a prescribed burn of DPHB8 at a time when there was an insignificant risk of smoke tainting the appellants' grapes; and the respondents took all reasonable steps to minimise the amount of smoke over the appellants' vineyards. However, it is unnecessary to determine this issue in view of my conclusion that the defence of statutory authority applies.

121 The defence of statutory authority requires that the nuisance be an 'inevitable consequence of the authorised undertaking'. If the nuisance was an inevitable consequence of the authorised undertaking, the defendant will only be liable if, in the exercise of its statutory powers, it acted negligently: Bankstown City Council v Alamdo Holdings Pty Ltd [2005] HCA 46; (2005) 223 CLR 660 [16]; Benning v Wong [1969] HCA 58; (1969) 122 CLR 249, 324 - 337 (Owen J). The reference to negligence is not to the tort. It is clear there is no requirement to prove that the defendant owed the plaintiff a duty of care.

122 In considering whether a nuisance is inevitable it is necessary to distinguish between statutory provisions that require a specified activity to be carried out and provisions that permit, but do not require, a specified activity to be carried out. In the former case there is no separate requirement of inevitability; any nuisance resulting from the activity will be authorised unless it is caused by negligence on the part of the person conducting the activity. All that is required is that the specified activity be executed (performed) with reasonable care. See Trindade, Cane and Lunney, The Law of Torts in Australia (4th ed) [4.1.6.3].

123 Where the statute permits the specified activity to be carried on, it must be shown that what the legislation authorised could not be done without creating a nuisance and that the nuisance was not caused by negligence. The inevitability limb focuses attention, not on the execution of the specified activity, but on the decisions relating to whether, when or how to undertake the authorised activity. Thus, if the creation of a nuisance could have been avoided by the proper exercise of the statutory power (ie one that was consistent with its scope and purpose(s)), the defence will fail even in the absence of negligence: Melaleuca Estate Pty Ltd v Port Stephens Council [2006] NSWCA 31 [48] - [57].

124 The escape of smoke from the prescribed burn on DPHB8 was the inevitable and unavoidable consequence of the Department's performance of its statutory function in the conduct of prescribed burning in the south-west forests of Western Australia. It is analogous to the 'railway sparks cases' referred to by Owen J in Benning v Wong (331). Further, the trial judge found that there was no negligence in the decisions relating to the burn of DPHB8 or in the execution of those decisions. Accordingly, the claim in nuisance must also fail.

125 In these circumstances, it is unnecessary to determine whether the CLA applies to a nuisance claim against a statutory authority. The answer to that question depends on whether, if the defendant has established inevitability, the onus is then on the claimant to establish negligence. On my reading, that question is answered affirmatively by Owen J in Benning v Wong (referred to with approval in Bankstown City Council [16], fn 24).

126 My preliminary view is that the CLA would only apply if the appellants had to prove negligence. Parts 1A and 1C of the CLA only apply where there is 'a claim for damages for harm caused by the fault of a person' even if they are sought to be recovered other than in an action for negligence (see s 5A(2) and s 5V(2)). The requirement for a causal link between the damage and the fault suggests fault must be an element of the cause of action. If so, it is not sufficient that fault may (not must) be relevant in an assessment of whether interference is unreasonable or that proven absence of fault is a material element of a defence to the nuisance claim.

128 Section 132 is headed 'Exemption from liability' and relevantly provides:

The Minister, the Executive Director, any person employed in the Department ... and any person who performs functions under this Act ... is not personally liable for anything done or omitted to be done by him in good faith in, or in connection with, the performance or purported performance of his functions under this Act.

129 The appellants pleaded that the first respondent 'is an agency or instrumentality of the second [respondent] in whom possession, occupancy or control of [DPHB8] is and was at the material time held and exercised for and behalf of the second [respondent]'. That is incorrect. The Department was in control of DPHB8 and any involvement of the first respondent was in his capacity as the Chief Executive Officer of the Department not in his corporate capacity.

130 The negligent act of which the appellants complain in their pleading is that the first respondent lit fires on DPHB8 from which thick noxious smoke was discharged onto the appellants' land thereby causing extensive damage to the grapes (par 10). They then plead that the discharge and escape of smoke was caused by the negligence of the respondents (par 11). The 'particulars of negligence' claim that 'the second [respondent] and its servants or agents were negligent in lighting the fires' in the ways particularised.

131 Although not pleaded, the issue of whether the State owed a non-delegable duty to the appellants was litigated (but not determined by the trial judge: [438] - [441]). That being so, there was a claim against the State based on both direct (personal) liability and vicarious liability: State of New South Wales v Lepore [2003] HCA 4; (2003) 212 CLR 511 [30], [32], [146], [151]. The principles relating to non-delegable duty, whether in relation to employers, agents or independent contractors, also apply to the Crown in right of the Commonwealth and States: Commonwealth v Introvigne (1982) 150 CLR 258.

132 All those involved on behalf of the State in the decisions relating to, and the execution of, prescribed burn DPHB8 were servants or agents of the State. The State is vicariously liable for the negligence of its servants or agents in the course of their employment. The question is whether the State also had a non-delegable duty to ensure that reasonable care was taken by its servants and agents in the performance of their functions.

133 If, contrary to my view, the servants and agents of the State owed a duty of care in the terms identified by Pullin JA, I would agree with his assessment that the State would be under a duty to ensure that its servants and agents exercised reasonable care to protect the appellants' grapes in the conduct of a prescribed burn. An owner of land who allows a dangerous activity to be performed on it owes a non-delegable duty to guard persons from the danger: Burnie Port Authority. It follows that the State has a non-delegable duty to ensure that its servants and agents exercise their power in relation to prescribed burns with reasonable care.

134 Smoke from a prescribed burn, although not itself intrinsically dangerous, is the unavoidable consequence of the burn and any assessment of reasonable care in relation to damage from smoke is inextricably intertwined with duties to others that are compatible with the statutory duty to conduct prescribed burns.

135 It is accepted by the respondents, correctly in my view, that s 132 provides no immunity to the State in relation to its direct (personal) liability for any negligence of the Department in relation to DPHB8. Therefore, I would dismiss the notice of contention.

136 PULLIN JA: This is an appeal against the judgment of Murphy J (as his Honour then was). His Honour dismissed a claim for damages brought by the appellants against the respondents.

137 Some of the appellants were grape growers and their grapes were tainted by smoke emitted by a 'prescribed burn' conducted by the first

respondent on 31 March 2004 and 1 April 2004. The burn was conducted on 560 hectares of land containing karri forest (described as DPHB8), which was a small part of the Donnelly District in the Warren National Park. DPHB8 was bordered by the Old Vasse Road, State Forest and the appellants' properties on the north-eastern boundary.

138 Grapes are particularly susceptible to smoke damage from the commencement of veraison (which is when the sugar content of the grapes reaches a certain percentage) to the end of harvest. The risk of smoke damage is at its highest seven days after the start of veraison and up to the time of harvest [433] and [487]. The date of those events varies from year to year, but usually occurred on the appellants' properties in January (start of veraison) and late March to early May (end of harvest) [10]. Early in the growth period of grapevines, which is up to the time when the vines flower, the risk of smoke damage is 'low' (see the evidence of Professor Gibberd, which the trial judge accepted [255] and [479(c)]). Then, in the period from when the berries are pea sized until about the start of veraison [261] there is more risk - a not insignificant risk - but no finding was made by the trial judge that in this period the risk was of 'serious harm', as was the case in relation to the burn of DPHB8 which affected grapes in the veraison to harvest period. The trial judge found, as will appear later, that the potential for harm at the time of the burn of DPHB8 was 'serious' because smoke taint could damage the whole of the appellants' grape crop [500] and [502] (which in fact came to pass).

139 In these reasons I will refer to the period from about the start of veraison until the completion of harvest as the 'veraison to harvest' period. The appellants' case at trial was that the prescribed burn should have been deferred and burnt some time later outside the veraison to harvest period.

(a) whether the respondents owed a duty of care to the appellants and if so, the content or scope of that duty;

(c) whether the respondents were liable to the appellants in nuisance and whether the claim in nuisance was pleaded (and, if pleaded, whether it was abandoned by the appellants at trial),

(d) whether s 132 of the Conservation and Land Management Act 1984 (WA) (CALM Act) indirectly provided the respondents with immunity from the appellants' claims for damages.

141 The respondents admitted at trial that smoke emitted by the burn of DPHB8 entered the appellants' properties, 'tainted' and, therefore, caused damage to grapes owned by some of the appellants on land owned by some of the appellants. The parties also agreed the quantum of damages [3].

142 It followed that if a duty of care was found to have been owed by the respondents to the appellants, and there was a finding of a breach of duty or the claim in nuisance could be established, and s 132 did not provide a defence, then the appellants were entitled to judgment against both respondents for the agreed sum.

143 At trial, the parties agreed to a course which is rarely a good idea. In opening the case, counsel for the appellants referred to the 'trial bundle' consisting of 14 volumes which the parties agreed could be tendered by consent. The 14 volumes became exhibit 1. A few documents were identified as requiring some evidence to prove them, but as to the rest, they all went into evidence. Many were not the subject of any oral evidence, and many, if not most, were not referred to in the trial judge's reasons. Very few were included in the appeal books. Apart from the documents in the appeal books and three additional documents taken from the exhibits and tendered at the appeal, no other exhibits were referred to in this appeal. It would be inadvisable in the circumstances for this court to go unassisted to the exhibits. As a result, the evidence referred to in these reasons is the evidence referred to by the trial judge in his reasons.

144 The trial judge found that no duty of care was owed by the respondents to the appellants and that even if a duty of care did exist, there was no breach of such duty. The trial judge did not give any consideration to a claim in nuisance. Why that was so will be revealed later in these reasons.

145 As to s 132 of the Act, the trial judge said that having regard to his findings on duty and breach, the proper construction of s 132 of the Act was not ultimately determinative of the action and because the debate on s 132 had lacked some clarity and focus it was unnecessary to come to a concluded view on the proper construction of the section [518].

146 The appellants were either the registered proprietors, or lessees of land containing vineyards. Although it was the appellants who were the lessees who suffered the damage, no point was taken about this and so reference will be made indiscriminately to 'the appellants'.

147 The first respondent was a body corporate capable of being sued (s 36(3) of the CALM Act) and was governed by the Chief Executive Officer of the Department of Conservation and Land Management (CALM) (s 36(4) of the CALM Act). CALM was a department of the second respondent. The second respondent is the State of Western Australia. Persons responsible for the conduct of the prescribed burn of DPHB8 were employees of the second respondent employed by CALM. As a result, attention will be concentrated on the question as to whether the second respondent was liable or not. Throughout these reasons, references to the respondents should be read as a reference to the second respondent.

Management of the DPHB8 land under the CALM Act

148 To ascertain what 'prescribed burn' means, it is necessary to refer to legislation, documents made pursuant to the legislation and other subsidiary documents. The DPHB8 land is Crown land in the Warren National Park and a 'national park' within the meaning of s 3 of the Act. It is land vested in the Conservation Commission, pursuant to s 7(3) of the CALM Act [393] - [394] but it was not managed by that body.

149 A function of CALM, subject to the direction and control of the Minister, was to manage land to which the CALM Act applied (s 33(1)(a)(i) of the CALM Act). There is no dispute that DPHB8 was land to which the CALM Act applied [394]. Section 33(3)(a) of the CALM Act provided that the management of the land and associated forest produce, flora and fauna 'shall' be carried out by CALM, where there was a management plan for the land, in accordance with that plan subject to the direction and control of the Minister. There was such a management plan for DPHB8.

The Management Plan - the Forest Management Plan

150 'Management plan' was defined in s 3 of the CALM Act as a management plan approved under s 60 of the CALM Act. Section 60(1) required the 'controlling body' (defined relevantly as the Conservation Commission (s 53)) to submit such a plan for the Minister's approval. The Forest Management Plan 2004 - 2013 was prepared and submitted, in accordance with the Act, for land vested in the Conservation Commission within, inter alia, the Warren region, part of which contained the Donnelly District which surrounds Manjimup, Pemberton and Northcliffe and within which lay DPHB8. The Forest Management Plan was approved under s 60 of the CALM Act by the Minister for the Environment on 10 December 2003 as required by s 60(2) of the CALM Act. Notice of the approval was published in the 'Government Gazette' on 19 December 2003.

151 The Forest Management Plan was in very general terms. It said nothing about the burning of DPHB8 or any particular area of land. It set out various objectives including the objective of:

(b) controlling 'adverse impacts of fire on the social, cultural and economic values of land managed by the Department and adjoining land [fire being a reference to wildfire and not prescribed burning [143]';

(c) minimising 'the risk of smoke emanating from prescribed burns impacting on population centres and other sensitive areas'.

152 Under a heading 'Actions proposed' was a statement that the Department would:

(a) 'prepare and maintain a fire management plan and smoke management guidelines';

(b) 'undertake an annual prescribed burning program in a manner that ... is in accordance with the fire management plan ... [and] ... in accordance with the smoke management guidelines'; and

(c) 'consult with stakeholders and interested community members' [142].

153 The trial judge construed the objective about minimising the risk of smoke from prescribed burns impacting on 'sensitive areas' to be a phrase 'capable of comprehending a reference to ... areas planted with grapes' [143]. That construction was not disputed by the parties to the appeal.

154 The CEO of CALM, therefore, had a duty to manage flora, fauna and land in the Warren National Park in accordance with the Forest Management Plan, but it was a matter for CALM to implement the plan subject to the direction and control of the Minister [398] by devising as it saw fit a programme of burns in the forest. A 'fire management plan' and 'smoke management guidelines' were prepared.

The Fire Management Plan - the Master Burn Plan

155 According to the Forest Management Plan a 'fire management plan' was to be prepared in 'Year 1' (GAB 147). One of the documents which was in exhibit 1 and not subject to the need for any evidence, was a plan entitled 'Six Season Indicative Master Burn Plan - Donnelly District'. This and other documents were referred to as the 'Master Burn Plan'. The trial judge held that the Master Burn Plan 'comprises planning at four levels' [164] and that:

(a) the first two levels were a 'three-year (ie six season) indicative burning plan' [164] and an annual indicative burning plan. The annual indicative burn plans were reviewed twice each year and if for 'operational or other reasons' a burn in the annual programme could not be carried out, it could be 'rolled over' into the burn programme for the following year [167];

(b) the third level involved the 'prescriptions for individual burns on the annual indicative burning plan' [164]. The burn prescription included a 'pre-burn checklist' which identified potential risks and impacts of the burn operations 'including smoke impacts' on 'neighbouring land' [170]. The purpose of the checklist was to provide the burn managers with an opportunity to identify the risks [and consequences] and to take steps to 'modify, postpone or cancel the burn' if the risks were significant and where the impact of smoke on population centres, airports, public roads and neighbouring properties was identified in the pre-burn checklist analysis, consideration was given to the wind direction, and lighting sequence and patterns that would minimise the risk of smoke 'impacts' [171];

(c) the fourth level consisted of 'daily operational scheduling of prescribed burns' settled upon via statewide telephone conferences by officers of CALM [174] and in the course of two telephone conferences, the final burn programme was settled upon for the day.

The first telephone conference was at 8.30 am in order to review the two-day weather forecast and synoptic information [176] and to agree on a final burn program after considering 'existing fire commitments, the level of resources available and smoke management' [177].

A final telephone conference occurred at 4.15 each day to consider the next four day weather forecast and synoptic information [178].

The provisions of the Fire Management Plan (the Master Burn Plan) relating to DPHB8

156 The respondents produced at the hearing of the appeal, a bundle of documents said to constitute the relevant Master Burn Plan (or at least part of it). It became exhibit 1 in the appeal. The bundle included a document entitled 'Spring 2003 Six Season Indicative Master Burn Plan - Donnelly District'. This document appears not to be the correct document because it shows that DPHB8 was to be burnt in spring 2003. Exhibit 1 also contained the annual burn plan relating to DPHB8 which also appeared to be irrelevant because it showed that it was to be burnt in spring 2003. The plan to burn in spring 2003 was not followed. It may be assumed, however, that there was a similar plan for 2004.

157 The 'prescription' for burning DPHB8 (GAB 173) in fact came into existence by a document dated 24 December 2001 under a previous master burn plan. It authorised DPHB8 to be burnt in spring/summer/autumn 2001/2002 (GAB 173 and [276]). The trial judge was evidently referred to other evidence because he recorded the fact that the burn prescription preparation for DPHB8 'commenced' in 1999 [271]. The burn was deferred or rolled over each year until 2004 when the burn occurred. The objectives for this burn, as stated in the 24 December 2001 prescription document, were:

1. To provide protection against wildfire damage to adjoining private property, to the mature forest within the National Park, park facilities and park visitors by creation of fuel reduced areas.
2. To protect and maintain biodiversity processes and ecological values within the burn by the application of a low intensity, slow moving prescribed burn that will provide a mosaic of burnt (70-90%) and unburnt (10-30%) patches.

158 Under the heading 'Environmental Issues' on the prescription appeared the heading 'Smoke' and it indicated that no action was required to deal with smoke, save to erect warning signs on the Old Vasse Road.

159 Subsequently, there were two written amendments to the 24 December 2001 prescription document. They were:

(a) a note prepared by Mr Marshall (the fire operations officer in CALM [272]) prepared shortly 'prior to' 7 February 2002 [196], [197] (the Marshall Amendment). The Marshall Amendment followed a discussion with Mr Pearse on behalf of the appellants. It was attached to the prescribed burn plan for DPHB8 and it read:

Murray Pearse ... has only found out ... recently that last year's grape crop was a complete loss. Murray said the grapes were smoke affected from last year's aerial burn ... (they had smoke blown across the grapevines for days). Murray said they could not afford to have this happen again ... he said the critical time would be from early December to mid-April. Murray is not against prescribed burning - he is only concerned with the smoke problem with the grapes. I suggest CALM carry out this burn with winds from the East to North-East. This will keep the smoke off the grape vines [197].

Although there was a dispute at trial about whether this was a variation to the burn prescription, the trial judge found that the Marshall Amendment did constitute such an amendment [198];

(b) a note prepared by Mr Gillard, the Donnelly District fire manager [133] dated 3 February 2004 (the Gillard Amendment). This was attached to the burn prescription for DPHB8 and the trial judge found that this also constituted an amendment [236]. It read:

Vineyards on 8945 and 8946 [two of the appellants' vineyards] will be an issue. The most susceptible varieties are on the western boundary. We need to complete the burn on ESE-E winds to minimise smoke over the vineyard. Murray Pearse ... is also happy for us to burn a strip of pasture inside the property if it will make the burn easier. Need to inspect in the field with Murray. This burn needs lots of resources with the aim of completing the burn in 2 days - again to minimise impact on the vineyard [236].

The Marshall Amendment, in effect, stated that the burn should be conducted on winds blowing from east to north-east, the objective being to 'keep the smoke off the grapevines' whereas the Gillard Amendment stated that burning was to be completed with 'ESE-E winds', the objective being not to keep smoke off the vineyards but to 'minimise smoke over the vineyard' and 'minimise' impact on the vineyard.

160 The Forest Management Plan required the preparation of smoke management guidelines within the first year. There was no oral evidence given at trial about Smoke Management Guidelines as required by the Forest Management Plan. However, among the documents tendered by consent at trial (exhibit 1.12.2811) was a document entitled 'Smoke Management and Air Quality'. On the first page headed 'Briefing Notes' it stated that:

The Department of CALM has worked closely with the Department of Environmental Protection and the Bureau of Meteorology to develop an agreed set of smoke management guidelines that will help to limit the incidence of undesirable smoke haze levels in Perth to less than 3 or 4 days a year.

161 The Smoke Management Guidelines were based on a number of strategies including 'maximising the use of upper winds from the north and west to blow smoke away from Perth and coastal centres'. There was no finding made by the trial judge that this document constituted the Smoke Management Guidelines referred to in the Forest Management Plan, but the respondents informed the court on appeal (and this was not disputed by the appellants) that this document did constitute the smoke management guidelines required under the Forest Management Plan (ts 9).

The provisions of the Smoke Management Guidelines relating to DPHB8

162 The Smoke Management Guidelines made no provision for minimising the risk of smoke emanating from prescribed burns 'impacting' on 'sensitive areas' other than in Perth.

The important points emerging from the Forest Management Plan and the documents produced pursuant to it

163 The Forest Management Plan and the documents made under it, namely the Fire Management Plan (the Master Burn Plan) and the Smoke Management Guidelines, contained a great deal of verbiage. Putting the verbiage aside, only three points in those documents need to be emphasised for the purpose of these reasons. They are:

(a) that CALM had a duty to manage the land referred to in the Forest Management Plan in accordance with that plan and to conduct an annual prescribed burning programme in accordance with the Fire Management Plan and the Smoke Management Guidelines;

(b) that CALM was left to decide via its Fire Management Plan where prescribed burns would be carried out and when and whether they would be carried out and, if burns were prescribed, CALM had the power to defer or cancel such burns. For example, if there was a risk of damage to property or life, CALM could elect not to burn as in fact occurred in the 2002-2003 season [283]. In short, CALM had the power but not the duty to conduct a prescribed burn on DPHB8.

(c) that if a prescribed burn were to be carried out it was to be carried out in a way that 'minimises the risk of smoke emanating from prescribed burns impacting on ... sensitive areas'. (As already mentioned, areas of vineyards in the Donnelly District were 'sensitive areas' and the appellants' vineyards were in a 'sensitive area'). The ordinary meaning of 'minimise' is to reduce to the smallest possible amount or degree (The Macquarie Dictionary).

164 Before 2001, CALM had not received any complaints about smoke affecting the quality of grapes [429]. However, a considerable amount of information became available after that date and CALM knew by March 2004 that smoke could damage grapes ([432], [493]).

165 The first notification of the effect of smoke on wine grapes came from the appellants themselves in 2001 [191]. As a result, officers within CALM suggested that vignerons should be treated as a stakeholder group to be dealt with when devising burn strategy [195].

166 In 2002, Mr Marshall prepared the Marshall Amendment. By May 2003, information had been received which led an officer in CALM to send an internal email expressing the view that there was no point in further research because there was compelling evidence about the effect of smoke on grapes [210].

167 In late 2003, a report (the Australian Wine Research Institute (AWRI) Report) received by CALM officers referred to 'conclusive evidence' that tainting of grapes and wine by bushfire smoke 'can occur' [221].

168 By January 2004, the Department had already responded to the prospect of a risk of smoke taint to grapes in another area. This was in an area described as DP 33, five kilometres to the north-west of Pemberton where a burn was deferred because of the 'smoke taint issue' [223]. Subsequently, that burn was conducted when the winds were blowing from the south-east [224] and away from the vineyards.

169 In the few weeks before the Gillard Amendment, there was an 'increased level of interest in the smoke issue with local winegrowers' [232]. In relation to another nearby prescribed burn, Mr Gillard said that he was not prepared to start the burn without departmental approval [230]. In relation to DPHB8, Mr Gillard said in an email report dated 23 January 2004, that because they were 'unable to complete this burn without smoke over the vineyards' he believed that 'this burn will also require corporate approval' [232].

170 On 27 January 2004, Mr Keppel briefed his superior, Mr Walker, stating that the issue had the potential to 'escalate into a political and legal situation if we go ahead and carry out the prescribed burns that put smoke over the vineyards adjacent to the area being burnt'. His email concluded:

For the above reasons I recommend the Executive Director and Minister be informed of the situation [233].

171 On 30 January 2004, Mr Keppel sent an email to Mr Gillard advising that CALM's position was that it would not delay the commencement of prescribed burns at the request of local wine grape growers [235]. As a result, Mr Gillard then prepared the Gillard Amendment. On the same day, viticultural consultants on behalf of the appellants, wrote a letter to Mr Gillard advising that any smoke entering the vineyard at that stage of the season would jeopardise fruit quality and fruit sales (GAB 170).

172 On 3 February 2004, Mr Walker, an officer in CALM drafted a 'Contentious Issue Briefing Note' titled 'Smoke From Prescribed Burning - Wine Grape Quality' [241] and provided it to Mr McNamara, who was the person holding the position of Executive Director of CALM (ie the first respondent). It was submitted to the Minister for the Environment on that day. The briefing note stated that:

The Department's position is that it will consult neighbours but the commencement and carrying out of prescribed burns will not be delayed at the request of individual wine grape growers. All prescribed burns will be commenced and carried out when the field conditions are suitable for the burn and resources are available [243].

The briefing note revealed (in par 2) that CALM understood that smoke should be minimised in the area 'where wine grapes are near to harvest'.

173 Questions were then put to the Minister, the first reading 'Will the Government request [the Department] to defer burns that may cause degradation to wine grapes?' The briefing note included a proposed response which the Minister might give which read: 'Not at this time. The government supports [the Department's] achievement of the prescribed burning programme'.

174 On 6 February 2004, the appellants' solicitors wrote to CALM advising that they would hold CALM liable if the burn proceeded and the grapes were damaged [245]. On 7 February 2004, the Minister for the Environment approved the Department's approach. This was done by the Minister handwriting on the note to the Minister attaching the contentious issue briefing note the words '[a]pproach (to continue prescribed burning) is supported' (GAB 167).

175 The greatest risk of smoke taint damage to grapes is now understood to be in the period seven days after the commencement of veraison to the end of harvest [261], [476]. The trial judge, in effect, found that at the time of the prescribed burn of DPHB8 in March/April 2004 it was foreseeable to the respondents that there was a not insignificant risk ([493], [496]) of harm in the form of smoke taint to the grapes growing on vineyards in the Donnelly District if smoke from a prescribed burn passed over unharvested vineyards in the period from veraison to harvest and that if such harm occurred, then 'it could damage the whole grape crop for the year' [502].

The weather forecasts for 31 March and 1 April 2004

176 Around 24 March 2004, a Regional Manager at CALM, Mr Keppel, formed the view that the burn of DPHB8 could best be carried out to avoid the risk of escape (presumably of fire) with southerly winds, but with an 'easterly component' to minimise smoke over the vineyard [291].

177 On 30 March 2004, Mr Marshall discussed the proposed burn with Mr Gillard. Mr Marshall and another officer advised that the forecast weather pattern would most likely be suitable to initiate the burn over the next few days, with winds initially in the south-east and then becoming north-east and east. It was agreed that this weather pattern would provide the best opportunity to safely complete the burn 'and to minimise smoke over the plaintiffs' vineyards' [293]. In the afternoon of 30 March 2004, Mr Gillard spoke to Mr Keppel, and discussed the four-day forecast. They discussed the potential for smoke to drift over the vineyards during the edging burn and the opportunity provided on 1 April to complete the core ignition while minimising the amount of smoke drift over the vineyards [294].

178 Around 31 March 2004, CALM's State Burn Coordinator received a personal briefing from the Weather Bureau's Duty Forecaster. Mr Gillard and Mr Keppel gave evidence, and the trial judge accepted, that they were informed that the duty forecaster had advised, in effect, that the weather system was moving through quickly and that undesirable north to north-west winds (and hence they inferred severe fire weather) could be expected in the next three to four days [295].

179 On the morning of 31 March 2004, there was a meeting of CALM's officers, including Mr Marshall and Mr Gillard at CALM's Pemberton office. They received the forecast issued at 7.50 am that morning and noted that south-south-east winds had been forecast for that day. They also noted that the outlook for the next day, 1 April, was for north-easterly winds in the morning and variable in the afternoon [298].

180 Mr Sneeuwjagt, who was the person within CALM who had to give his approval to start the burn on that day, viewed the smoke trajectory model from the Weather Bureau which indicated that smoke emanating from a location near Pemberton would be blown slightly west of north-west. This confirmed, in his mind, that the bulk of the smoke from the edge burn on 31 March should be blown away from the appellants' vineyards located north-east of DPHB8 [300]. Mr Sneeuwjagt gave evidence that he had the objective of 'minimising the impact' [507] which was in accordance with the objective in the Gillard Amendment but not the objective in the Marshall Amendment which was to 'keep smoke off the grapes' [197]. He then gave his approval [300].

181 The burning of edges near the appellants' vineyards was commenced late morning and continued through the remainder of 31 March 2004. This burnt out approximately 120 hectares, of which 20 hectares covered the area adjacent to the south and east of the appellants' vineyards [313].

182 On 1 April 2004, Mr Marshall requested approval from Mr Keppel to complete the core ignition. Approval for the burn was also received from Mr Sneeuwjagt and at 11.00 am, the core ignition commenced by aerial ignition and the burn was completed by the evening [317] - [318].

183 In conducting the burn, it is clear that CALM officers took control of DPHB8. The burn prescription reveals that it put in bulldozers and graders to 'push back overgrown vegetation from boundary tracks and clear turnarounds' and to 'grade boundary where required' (GAB 174).

(a) on 31 March there was smoke over the vineyard by about 12.30 pm, and it stayed over the vineyard for the rest of the day. The smoke at night was not as heavy;

(b) on 1 April the smoke blew off the property in the morning by the north-east wind but returned at about midday, stayed over the property, and was fairly dense;

(c) by 2 April the smoke had moved off the vineyards but returned at about 3.30 pm;

(d) on 3 April the sky was fairly clear of smoke until about 4.00 pm when smoke again covered the vineyards;

(e) on 4 April there was smoke over the vineyards but it was less dense;

(f) on 5 April there was again smoke over the vineyards with about the same density as the smoke level on 4 April [323].

The respondents admit that this smoke caused over $600,000 of damage to the appellants' grapes.

185 The trial judge found that the passage of smoke over the vineyards reflected the potential for variance between forecast winds and actual conditions. He noted that although the winds for 1 April to 3 April were forecast to be north-east and east, on each of those days the actual winds had a southerly component, particularly in the afternoon [325].

186 The statement of claim asserted that the respondents 'lit fires' without taking 'reasonable precautions' and that 'weather conditions' were unsuitable or that they 'lit fires' when they 'could have [been] delayed ... until after the grapes ... had been harvested' (BAB 138). In effect, the appellants alleged a failure to take 'precautions': see s 5B(1) of the Civil Liability Act 2002 (WA) (CLA). The precautions the appellants contended for at trial were that:

(a) the burn of DPHB8 should have been carried out outside the veraison to harvest period by rolling over the prescribed burn and burning it in a subsequent year outside the veraison to harvest period [451];

(b) if the burn was carried out in the veraison to harvest period, then it should have been carried out at some time in that season in accordance with the Marshall Amendment on winds forecast to be from the north-east which the appellants contended would have carried smoke away from the vineyards (trial ts 1104).

(c) as a particular of the previous precaution, the appellants contended that the burn should have been deferred for one day [453] because on the first day the winds were forecast to be from the south-east and on the following two days, the forecast was that winds would blow from the north-east. Alternatively, the burn could have been carried out in the veraison to harvest period in a subsequent season when winds were forecast from the north-east on all days.

187 In support, the appellants led expert evidence from Dr Tolhurst to the effect, inter alia, that the burn could have been carried out on various dates outside the veraison to harvest period and that the precaution could have been taken of conducting the burn of DPHB8 when winds were blowing from the north, because this would have carried smoke away from the appellants' vineyards. However, at a pre-trial conference he agreed with the other experts that it was not possible to burn DPHB8 without putting some smoke over the appellants' vineyard [370].

188 At trial, the appellants submitted that the respondents' duty in managing the forest, was a duty 'not to cause harm' to the appellants' vineyards by the lighting of fires in the forest adjacent to the vineyards [437].

The trial judge's reasons for decision concerning the existence of a duty of care

189 The trial judge rejected the appellants' formulation of the duty of care and observed that any duty, if it existed, required no more than the exercise of reasonable care.

190 The trial judge said that any arguable duty would be 'along the following lines - that in planning and carrying out prescribed burns on land which is adjacent to or in close proximity to vineyards, the defendants owe a duty to exercise reasonable care to avoid the risk of smoke taint or damage to the fruit or vines on the vineyards' [445].

191 His Honour referred to s 5W of the CLA which he observed had to be considered in relation to whether a duty of care was owed by the respondents but, thereafter, did not make any findings about the matters listed in s 5W(a) - (d) in relation to the duty issue: see [460] - [490].

192 The trial judge made the following relevant findings of fact. The first finding (or rather group of findings) dealt with the issue of wind direction and the appellants' submission based upon the evidence of Dr Tolhurst that the burn should have been conducted when the wind was blowing from the north to north-west. The trial judge found the safest burns in the south-west forests were undertaken when the winds were from the south (SE to SW), that the most dangerous winds were from the north and northwest continental winds and that a burn prescription for DPHB8 on north to north-west winds would be inappropriate [352] - [354] but that 'north easterly winds, particularly of a gentle velocity' did not 'present the danger associated with north-westerly winds' [428] (this presumably refers to danger from the escape of the fire onto other property). The second finding was that 'practically speaking, the time when it is safe and effective to carry out prescribed burning in karri forests with K1 and K2 understorey is the time when the grapes are at stages of development where smoke taint poses a not insignificant risk' [488], ie between veraison and harvest.

193 The third finding was based on the trial judge's acceptance of Mr Mr Sneeuwjagt's evidence that the burn was carried out when the winds were from the south to south-east and that he allowed the burn to go ahead on 31 March 2004 under those winds to minimise the impact of smoke [507]. At [495] the trial judge found that the core ignition burn exhibited characteristics of fire and smoke intensity which would not be dissimilar to a bushfire, that in the course of a burn over several days there was a significant chance of the occurrence of swings and changes in wind direction, and that there was a not insignificant risk that winds would move around from time to time in the course of the burn [495].

194 The trial judge stated that on 'one view', the appellants' case involved the proposition that the Department should not have carried out the prescribed burn of DPHB8 in order to avoid the risk of smoke taint to the grapes. The trial judge held this to be inconsistent with the statutory functions of the Department [481]. He stated that if the appellants' case was characterised as a claim that the Department had a common law duty that made its statutory duty subservient to the common law duty, then that would be inconsistent with the statutory scheme [482] and such a common law duty would tend to 'distort, by skewing, the focus of the statutory decision-making process, and distort the performance of the Department's statutory functions' [484].

195 The trial judge found that the respondents did not owe a duty of care to the appellants [490].

Trial judge's findings and provisional decision in relation to breach of duty

196 The trial judge then went on to consider the question of breach of duty in case he was wrong in finding that a duty of care was not owed to the appellants.

197 The trial judge made a great number of detailed findings which relate to the breach of duty issue. After making the detailed findings, the trial judge set out the 'broad context' of his findings in [406]. That paragraph read:

The decision to burn DPHB8 on 31 March 2004 was made in the following broad context:

(a) the area was nearby to a significant town, Pemberton, and formed part of an important National Park. The burn had a high strategic value in the prescribed burning programme;

(b) the area had a fuel load of 73 - 93 tonnes per hectare, when the limit at which wildfire in karri forest can generally be controlled in most weather conditions is under 19 tonnes per hectare;

(c) the area also had tactical value within the overall burning programme in that, once burned, it would provide an area of low fuel from which to burn other very high fuel areas to the south;

(d) it was in dense karri forest with predominantly K1 and K2 understorey, which meant that there was a limited opportunity effectively and safely to carry out a burn. Essentially, its location and vegetation meant that it could not be properly burned at any time in the period May to at least mid-December inclusive, it was likely to become unsuitable for burning at some time in April and even in January to March/mid-April there was no assurance of favourable wind and weather conditions;

(e) it was a burn which had been introduced as part of the Master Burn Plan into the six-season burn programme in 1999, and which had remained unburned for several years because of resource limitations and the absence of favourable burning conditions;

(f) the forecast weather conditions for the period 31 March to 3 April 2004 indicated that the burn could be conducted safely and effectively within that period;

(g) the burn would serve important objectives, in accordance with the Forest Management Plan. The objectives, referred to in the burn prescription, were the protection against wildfire damage to nearby private property, and to the mature forest within the Warren National Park, and to park facilities, and also to visitors who used the park for recreational purposes, and the protection and maintenance of the biodiversity processes and ecological values;

(h) if the burn was delayed, there was no guarantee that a combination of propitious conditions and adequate resources would converge to ensure that the burn occurred in the following year, or even in subsequent years;

(i) there had been a backlog of prescribed burning and the State had recently (in 2003) experienced its worst bushfires for many years and there had also been, at a national level, the experience of the terrible bushfires in Canberra, New South Wales and Victoria in 2002/2003;

(j) the south-west forests are fire-prone, and are at real risk of wildfire from both lightning and anthropogenic causes;

(k) wildfire has potentially devastating consequences, including loss of life and destruction of private and public assets and the environment; and

(l) prescribed burning is the cheapest and most ecologically sound way to reduce fuel loads, and thereby to reduce the risk of uncontrollable high-intensity wildfires [406].

198 Further, it is necessary to record some of the evidence and the findings made about when prescribed burning could be carried out in K1 and K2 karri forest, which is the type of flora found on DPHB8 [47]. The trial judge began this section of his reasons under the heading 'The window of opportunity for prescribed burning in the Warren Region' [326]. His Honour then referred to an overview by Dr McCaw, which was that the window of opportunity for prescribed burning in south-west forests is influenced by a number of unsurprising factors such as the nature of the forest, the density and species composition of understorey, soil types, elevation and prevailing patterns of weather. It is important to distinguish between the evidence and his Honour's findings about when it was impossible to carry out prescribed burning and when 'generally' prescribed burning could be carried out. His Honour at [326] appeared to accept one of the experts, Dr McCaw's evidence that 'effective prescribed burning [cannot] be conducted in karri forests between May and October, unless the forest has been modified by timber harvesting, partial clearing or removal of the understorey shrub layer'.

199 From then on, in that section, his Honour recorded what was 'generally' or 'usually' the case. Thus, for example, the trial judge recorded that in forests with K1 and K2 understorey: the forest will 'usually' not be dry enough to burn until late December to mid-January [362]; that 'generally' karri forests are too wet to burn in April and May [328]; that 'in most years' the karri fuels do not dry out sufficiently to achieve a satisfactory fuel reduction outcome until early to mid-December; that they become too dry in late January to mid-March before they again reach satisfactory levels after light rainfall in early autumn (late March/early April) [340]; and after 'mid to late April' the karri fuels generally become too moist to burn due to other rainfall or overnight dew [340]. In 'most years' the number of days in a year with suitable fuel moisture within mixed karri forests in the Pemberton area is less than 12 and can be as few as two days [341]. K1 and K2 karri will 'usually' not be sufficiently dry until the Soil Dryness Index exceeds 800 and that is 'generally' not exceeded until late December to mid-January and falls below 800 in April each year [362]. Mr Muller, an expert whose evidence the trial judge accepted (see [376]) said in his evidence that 'on average' there are only between one and seven suitable burning days outside the veraison to harvest period [374]. He also gave evidence that it was not possible to maintain an 'effective' fuel reduction burning programme if burning was restricted to outside the veraison to harvest period. However, he then added that the 'threat of smoke affecting grapes can be reduced if a higher priority is given to burning those areas closest to vineyards on the days available prior to veraison where this is possible and conducting more distant burns later in the season' [374].

200 From all of this evidence, the conclusion to be drawn is that it was impossible to carry out prescribed burning between May and October and that burns outside that period, that is, from November to April, could be carried out depending upon conditions. What was 'usually' or 'generally' the case would have made planning to burn in K1 and K2 karri forest more difficult, but not impossible.

201 His Honour observed that the question of breach of duty had to be considered by reference to s 5B of the CLA [493]. The trial judge identified the 'risk of harm' as being the risk to grapes of smoke taint [493]. The 'precautions' which the appellants contended the respondents should have taken are set out above . His Honour considered s 5B of the CLA and found that:

(a) as to s 5B(2)(a), that 'the risk of smoke taint to grapes, whilst not insignificant, would not ... be regarded as high', meaning that the probability that the harm would occur if care were not taken was not high;

(b) as to s 5B(2)(b), that the nature of the potential harm from the core ignition was serious in that smoke taint could well destroy the economic value of the plaintiffs' harvest for that year;

(c) as to s 5B(2)(c), that the burden of the precaution was 'deferring the burn (including wasted opportunity when opportunities are limited)';

(d) as to s 5B(2)(d), the carrying out of the prescribed burn had 'important social utility'.

202 The trial judge weighed up these four factors and held that the 'burden' of deferring the burn until sometime outside the veraison to harvest period and the important social utility of the burn outweighed the foreseeable risk of harm and the seriousness of that risk [500]. As a result, the trial judge held that a reasonable person in the position of the respondents would not have 'rolled over' or otherwise deferred the burn [501].

203 The trial judge also found that any 'fault' by the Department in deciding to carry out the burn on 31 March 2004 or in failing to defer the burn, was in substance a policy decision in the performance of a public function and that such a policy decision could not be used to support a finding of fault by reason of s 5X of the CLA [511]. The trial judge also referred to s 5W(d) of the CLA and held that there had been a 'proper exercise of' CALM's functions that 'provide grounds for confirming that if ... a duty of care exists, it was not breached' [509].

204 As to the contention that the precaution should have been taken of deferring the burn for one day, the trial judge held that the probability that harm would occur from the edge burning on the first day was low [502]. In fact, he found that the edge burn did not carry a high 'or even significant probability' of harm. His Honour held that the deferral of edge burning for a day would not, in the context of the burn in its entirety, have materially altered the probability of the risk of harm.

205 The trial judge's provisional finding was that if there were a duty of care owed to the appellants there was no breach of duty.

The judge's reasons concerning s 132 of the CALM Act

206 The trial judge decided that it was unnecessary to come to a concluded view on the proper construction of s 132. The trial judge, however, referred to the fact that the appellants had submitted that a non-delegable duty of care was owed by CALM [515], this submission being based on Burnie Port Authority v General Jones Pty Ltd [1994] HCA 13; (1994) 179 CLR 520. The trial judge expressed the view that the case did not involve a non-delegable duty of care and that the State could only be liable on the basis of vicarious liability but did not deal with the issue because of his 'findings on duty and breach' and because the debate on s 132 had lacked clarity and focus [518].

207 As a result of the foregoing, the appellants' action was dismissed.

208 The written and oral submissions from the appellants were unfocused. It is, therefore, especially important to glean from the grounds of appeal the issues which govern the determination of this appeal.

209 The appellants contend by their grounds of appeal:

(a) by grounds 1 - 5 and 12, that the trial judge erred in finding that the respondents owed no duty of care to the appellants;

(b) by grounds 6, 8 and 13, the appellants allege that the trial judge erred in finding that there was no breach of duty. In particular, ground 8 alleges that the trial judge erred in his weighting of the competing considerations which the court has to consider under s 5B(2) of the CLA;

(c) by grounds 9 to 11, the appellants allege that the trial judge erred in concluding that s 5W and s 5X had any application in deciding whether there was a breach of duty;

(d) by grounds 13 and 14 the appellants allege that the trial judge erred in failing to deal with a cause of action in nuisance which the appellants contend was live.

210 This is an appeal by way of rehearing. The form of rehearing shapes the requirements and limitations of the appeal: Fox v Percy [2003] HCA 22; (2003) 214 CLR 118 [23]. The relevant 'requirements' are that the appellate court is obliged to conduct a real rehearing. It is not confined to reconsideration of the record in order to correct errors of law, although that will be encompassed in an appeal: CSR Ltd v Della Maddalena [2006] HCA 1; (2006) 80 ALJR 458 [16]. Having conducted a rehearing, the appellate court is obliged to 'give the judgment which in its opinion ought to have been given in the first instance': CSR [16]. This is a case where the reasoning rested on inferences drawn from facts that were undisputed or found by the trial judge: CSR [20]. Where the conclusion of the primary judge depends on inferences drawn from undisputed facts or facts that have been found that can equally be re-determined by the appellate court, without relevant disadvantage, the duty of the appellate court is clear. Although 'respect and weight' is given to the conclusion of the trial judge, the appellate court having reached its own conclusion, must not 'shrink from giving effect' to its own conclusion and substituting it for the conclusion reached by the trial judge: CSR [22].

211 In this case, there were some instances of disputed facts, but those were resolved by findings made at trial and the grounds of appeal do not challenge any of those findings. The appellants challenge the trial judge's conclusion of law that there was no duty of care based on the facts as found and challenges the ultimate finding of fact, based on a weighing of competing considerations, that there was no breach of duty. This court is in the same position as the trial judge. It is required to reach its own conclusions and draw its own inferences: CSR [16]. The parties were satisfied that the thorough review of the evidence and the detailed findings made by the trial judge made it unnecessary for this court to reread the evidence and examine the whole record (ts 126). In addition, as already mentioned, it would be difficult to do so because of the way the exhibits were tendered. The court was not provided with the whole record in the appeal books.

Civil Liability Act 2002 (WA) (CLA)

212 In considering the issues of duty and breach, it is important that attention be directed first to the CLA to avoid the risk that inquiries about those issues will miscarry: Adeels Palace Pty Ltd v Moubarak [2009] HCA 48; (2009) 239 CLR 420 [11]. The sections in the CLA which are relevant and which require consideration are as follows:

In this Act, unless the contrary intention appears -

harm means harm of any kind, including the following -

(a) personal injury;

(b) damage to property;

(c) economic loss;

...

This Act binds the Crown in right of the State and, in so far as the legislative power of Parliament permits, the Crown in all its other capacities.

213 Part 1A is headed 'Liability for harm caused by the fault of a person'. Section 5A(1) and (2) read:

(1) Subject to sections 3A and 4A, this Part applies to any claim for damages for harm caused by the fault of a person unless this section states otherwise.

(2) This Part extends to a claim for damages for harm caused by the fault of a person even if the damages are sought to be recovered in an action for breach of contract or any other action.

214 Division 2 is headed 'Duty of Care'. Under it appears:

(1) A person is not liable for harm caused by that person's fault in failing to take precautions against a risk of harm unless -

(a) the risk was foreseeable (that is, it is a risk of which the person knew or ought to have known);

(b) the risk was not insignificant; and

(c) in the circumstances, a reasonable person in the person's position would have taken those precautions.

(2) In determining whether a reasonable person would have taken precautions against a risk of harm, the court is to consider the following (amongst other relevant things) -

(a) the probability that the harm would occur if care were not taken;

(b) the likely seriousness of the harm;

(c) the burden of taking precautions to avoid the risk of harm;

(d) the social utility of the activity that creates the risk of harm.

215 Part 1C is headed 'Liability relating to public function':

policy decision means a decision based substantially on financial, economic, political or social factors or constraints;

(a) the Crown (within the meaning of the Crown Suits Act 1947);

...

(g) a body that is established or continued for a public purpose under a written law;

...

(1) Subject to sections 3A and 4A, this Part applies to any claim for damages for harm caused by the fault of a person unless this section states otherwise.

(2) This Part extends to a claim for harm caused by the fault of a person even if the damages are sought to be recovered in an action for breach of contract or any other action

...

5W. Principles concerning resources, responsibilities etc. of public body or officer

The following principles apply in determining whether a public body or officer has a duty of care or has breached a duty of care in proceedings in relation to a claim to which this Part applies -

(a) the functions required to be exercised by the public body or officer are limited by the financial and other resources that are reasonably available to the public body or officer for the purpose of exercising those functions;

(b) the general allocation of those resources by the public body or officer is not open to challenge;

(c) the functions required to be exercised by the public body or officer are to be determined by reference to the broad range of its activities (and not merely by reference to the matter to which the proceedings relate);

(d) the public body or officer may rely on evidence of its compliance with the general procedures and applicable standards for the exercise of its functions as evidence of the proper exercise of its functions in the matter to which the proceedings relate.

In a claim for damages for harm caused by the fault of a public body or officer arising out of fault in the performance or non-performance of a public function, a policy decision cannot be used to support a finding that the defendant was at fault unless the decision was so unreasonable that no reasonable public body or officer in the defendant's position could have made it.

Was a duty of care owed by the respondents?

216 Whether a duty of care exists is a matter of law. Although the determination of the existence of a duty of care is 'sometimes' more complicated than it was in Lord Atkin's time: Roads and Traffic Authority of New South Wales v Dederer [2007] HCA 42; (2007) 234 CLR 330 [44], as will appear below, this is not such a case. In order to consider whether a duty of care is owed by a defendant in a case, it is sensible to first determine whether the relationship between the respondents and the appellants fell into some established category where it is uncontroversial that a duty of care is owed. Most actions in tort which come before the trial courts arise out of relationships in which the existence of a duty of care is well established, and the nature of the duty is well understood. References to duty of care, breach of duty and causation provide convenient subheadings for a judgment, but in many cases the concepts require no further analysis: Modbury Triangle Shopping Centre Pty Ltd v Anzil [2000] HCA 61; (2000) 205 CLR 254 [13], Gleeson CJ (Gaudron & Hayne JJ agreeing).

217 It would seem remarkable that the respondents should owe no duty of care. If that were so, it would mean that the respondents could exercise the statutory power to light a fire in the forest careless about the damage it might do to neighbouring properties either from smoke or escape of the fire. Some very plain language would have to be used in the legislation to bring about that result. No such language was used.

218 It has been 'well established' in cases for well over a century that statutory powers, if exercised, must be exercised with reasonable care in order to avoid foreseeable risk of harm to those who might be injured if such care is not taken: Geddis v Proprietors of Bann Reservoir (1878) 3 App Cas 430, 455 - 456 (Lord Blackburn); Caledonian Collieries Ltd v Speirs [1957] HCA 14; (1957) 97 CLR 202, 220 (Dixon CJ, McTiernan, Kitto and Taylor JJ); Benning v Wong [1969] HCA 58; (1969) 122 CLR 249, 256 (Barwick CJ); Sutherland Shire Council v Heyman [1985] HCA 41; (1985) 157 CLR 424, 458 (Mason J), 436 (Gibbs CJ); Crimmins v Stevedoring Industry Finance Committee [1999] HCA 59; (1999) 200 CLR 1 [62] (McHugh J); Stuart v Kirkland-Veenstra [2009] HCA 15; (2009) 237 CLR 215 [117] and Sydney Water Corporation v Turano [2009] HCA 42; (2009) 239 CLR 51 [44]. The officers of CALM were exercising statutory powers to carry out the prescribed burn.

219 This is a case where it is settled that a duty of care is owed. This was settled in Burnie Port Authority v General Jones Pty Ltd. It was held there that the rule in Rylands v Fletcher [1868] UKHL 1; (1868) LR 3 HL 330, with all its difficulties and uncertainties, should now be seen as absorbed by the principles of ordinary negligence. The plurality then said:

Under those principles, a person who takes advantage of his or her control of premises to introduce a dangerous substance, to carry on a dangerous activity, or to allow another to do one of those things, owes a duty of reasonable care to avoid a reasonably foreseeable risk of injury or damage to the person or property of another (556).

220 Setting fire to a forest is a dangerous activity. It is an activity involving 'exceptional danger': Hazelwood v Webber [1934] HCA 62; (1934) 52 CLR 268, 279; Burnie (555). The duty of care owed is a non-delegable duty of care (555), as was made plain by the plurality in Burnie when they said:

In a case where the person or property of the other person is lawfully in a place outside the premises that duty of care both varies in degree according to the magnitude of the risk involved and extends to ensuring that such care is taken (557) (emphasis added).

221 The fact that the greater risk of damage is from the escape of the fire rather than damage caused by smoke from the fire, does not mean that the nature of the duty differs depending on the nature of the damage. The kind of damage suffered may be relevant in some cases to the existence and nature of a duty of care: see Cole v South Tweed Heads Rugby League Football Club Ltd [2004] HCA 29; (2004) 217 CLR 469 [1] (Gleeson CJ); Sutherland Shire Council (487) (Brennan J). Those cases, however, did not involve established categories of duty and were concerned with omissions, there being an indirect relationship between the defendant's actions and the ensuing harm.

222 In cases falling into established categories, all that it is usually necessary to say is that the duty is to use 'reasonable care' to avoid foreseeable risk of injury. In Kuhl v Zurich Financial Services Australia Ltd [2011] HCA 11; (2011) 243 CLR 361 [22] (French CJ & Gummow J) it was said:

In many cases a duty formulated as being one to take 'reasonable care' may suffice for the finding of duty in that particular case. Cases that involve the duty of a solicitor to his or her client to exercise professional skill in accordance with the retainer, the duty of a motorist towards other users of the road, or the duty owed by an occupier of land to an entrant with respect to the condition of the premises, ordinarily involve no real controversy over the scope and content of the duty of care; these are considered at the 'high level of abstraction' spoken of by Glass JA in Shirt v Wyong Shire Council [1978] 1 NSWLR 631 at 639.

(See also Sydney Water Corporation v Turano [45]).

223 French CJ and Gummow J explained that only outside of the well-recognised categories was the situation different, and that a duty formulated at too high a level of abstraction may leave unanswered the critical questions respecting the content of the term 'reasonable' and hence the content of the duty of care. Those observations do not apply in this case.

224 The duty must be expressed in terms of a duty to the plaintiff or a class of which the plaintiff is a member: Modbury [104]. The duty was owed to grape growers in the 'area', a phrase which the respondent agreed was a reference to the Donnelly District shown on exhibit 33B.

225 The damage in this case was caused by the direct and foreseeable consequence of carrying out a burn which resulted in smoke infiltrating the appellants' vineyards. Hayne J in Modbury said that where the 'extent' of the relevant duty is 'not clear', it is 'useful' to begin by considering the damage which the plaintiff suffered, and the particular want of care which is alleged against the defendant [105]. In this case, the existence of a duty is clear so resort to the course which is useful in more marginal cases is not required. The damage suffered by the appellants was a direct and foreseeable result of the smoke from the prescribed burn.

226 Although s 5W of the CLA states some principles which are said to apply in determining whether a public body or officer 'has a duty of care', neither party made submissions that would have any significance in this case about the existence of a duty of care.

227 The need to avoid the Scylla of lack of precision, and the Charybdis of too broad a statement of the scope of the duty (see Hayne J in Modbury [103] and Sydney Water Corporation v Turano [45]) arises particularly where the court has to grapple with a novel situation and is concerned about whether a duty exists at all: Kuhl [22]. In the ordinary case of an allegedly negligent act occurring in one of the established categories, no such problem arises: Kuhl [22].

228 The respondents did owe a duty of care. When conducting a prescribed burn on DPHB8 pursuant to its statutory power, the respondents owed a non-delegable duty to grape growers in the Donnelly District to ensure that reasonable care was taken by CALM employees to avoid reasonably foreseeable risk of smoke damage to the grape growers' grapes.

229 Ground 1 alleges that the trial judge erred in holding that a duty of care was not owed to the appellants. As will become apparent later in these reasons, contrary to the trial judge's conclusion [481] - [482], there was no incompatibility between the statutory power and the existence of a common law duty. The ground should be upheld.

230 Once a case is identified as one where a defendant owed a non-delegable duty to ensure that reasonable care was exercised to avoid foreseeable risks of injury, the court is then concerned with more particularity. The standard of care to be exacted in a particular case is that which is reasonable in the circumstances: Burnie Port Authority (554).

231 It is at this stage that it is necessary to determine what it is that the defendant should have done and which it did not do in the discharge of its duty. Under the CLA, the inquiry is couched in terms of the 'precautions' the defendant had to take to avoid the harm.

232 Section 5B(1) of the CLA provides that a person is not liable for harm caused by that person's 'fault' in failing to take precautions against a risk of harm unless:

(a) the risk was foreseeable (that is, it is a risk of which the person knew or ought to have known);

(c) in the circumstances, a reasonable person in the person's position would have taken those precautions.

233 'Harm' is defined in the CLA as including damage to property (s 3). 'Fault' is not defined. This expression must include a breach of a duty of care imposed by law.

234 Section 5A(2) of the CLA provides that pt 1A 'extends to a claim for damages for harm caused by the fault of a person even if the damages are sought to be recovered in an action for breach of contract or any other action'. Section 5B of the CLA is in pt 1A. A person who causes harm by breaching a general law duty to exercise reasonable care to avoid a foreseeable risk of injury, is at 'fault' in failing to take the precautions which a reasonable person in the person's position would have taken.

235 Section 5B(1)(c) is directed to the conventional inquiry about what a person is required to do once it is established that there is a duty of care owed. Precautions which must be taken are those which, in the circumstances, a reasonable person in the defendant's position would have taken.

236 Section 5B(2) of the CLA states what the court must consider in making a determination about whether a reasonable person in the respondents' position would have taken the precautions under consideration. This is in effect a statutory statement of what is sometimes called the 'Shirt calculus' with minor adjustments: see Wyong Shire Council v Shirt [1980] HCA 12; (1980) 146 CLR 40, 47 (Mason J); the Ipp Report 7.9; Vairy v Wyong Shire Council [2005] HCA 62; (2005) 223 CLR 422 [128] (Hayne J). Section 5B(2) is set out above. It states four 'things' which must be considered in deciding whether a reasonable person would have taken precautions. The only other relevant thing to be considered (other than those listed in s 5B(2)(a) - (d)) was the fact that the respondent had statutory power to carry out the burn.

237 The considerations in (a) and (b) are to be weighed against the considerations referred to in (c) and (d). (This construction is confirmed by the Ipp Report 7.9). The higher the probability that harm would occur and the more serious the harm, the more likely that those factors will outweigh the other factors, and the more likely that the determination will be that a reasonable person would have taken precautions. If the factors in (c) and (d) exceed the weight given to (a) and (b) then it is likely that the determination will be to the contrary.

238 Section 5B(1) and (2) requires an identification of the 'harm' and the 'precautions' which it is alleged the respondents should have taken and then the balancing of the relevant things referred to in s 5B(2).

239 The relevant harm was 'damage to property', being smoke damage to the appellants' grape crop.

240 Ground 6 alleges that the trial judge erred in finding no breach of duty. The particulars to this ground should at least have expressly identified the precautions which the appellants allege the trial judge should have found as the precautions to be taken. Unfortunately the particulars, like the submissions, were unfocused. One particular, particular (vii)(C), contends that the trial judge 'should have found that it was not possible to avoid foreseeable damage' if the burning of DPHB8 was commenced during the veraison to harvest period. In other words, and by implication, the appellants allege that the burn should have been deferred so that the burn could take place outside the veraison to harvest period, either later in that season or in some other season. The respondents, in their written submissions, gleaned this from the grounds because they said in par 37 that the gravamen of ground 6 and some of the particulars was that by failing to defer the DPHB8 burn until after the appellants had harvested their grapes, the respondents breached the duty of care.

241 The appellants' contention at trial that the CALM employees should have taken the precaution of deferring the burn only for one day was not pursued on appeal.

242 At the hearing of the appeal, and during oral submissions, the appellants' counsel, without abandoning the grounds of appeal, argued strenuously in support of a contention that the precaution which should have been taken was to never burn DPHB8 at all. That amounted to a submission that the statutory power to burn should never be exercised. For reasons given later in these reasons, that argument has no merit and must be rejected.

243 The first question which has to be considered is whether the findings made by the trial judge left it open to the appellants to contend that burning DPHB8 outside the veraison to harvest period was an option. If not, then the suggested precaution would amount to the same thing as the appellants' impermissible argument that the statutory power should never be exercised. That requires consideration of what the trial judge decided on this point. At [488] the trial judge said:

[P]ractically speaking, the time when it is safe and effective to carry out prescribed burning in karri forest with K1 and K2 understorey is the time when the grapes are at stages of development where smoke taint poses a not insignificant risk. A duty to exercise reasonable care to avoid the risk of smoke taint to the plaintiffs' grapes in planning and implementing a prescribed burn would involve the imposition of a legal obligation which was, in practical terms, incapable of being discharged.

244 The use of the phrases 'practically speaking' and 'in practical terms' when saying when DPHB8 could be burnt raises a question as to why the trial judge said that. He did not say that it was impossible to carry out a prescribed burn on DPHB8 outside of the veraison to harvest period. If that is what the trial judge meant, then there was no point in suggesting a deferral because that would mean that burning of DPHB8 could never be carried out.

245 However, what the trial judge said at [488] was not all that was said on the subject. The trial judge said at [500] that deferring the burn would have wasted an opportunity to burn when opportunities were 'limited'. I have set out above the findings indicating that burning K1 and K2 karri forest was impossible from May to October each year, but possible from November until April inclusive, albeit with various restraints on burning in that period [487(a)]. It was possible in certain years to burn outside the veraison to harvest period. That would be in the period from mid to late December until the start of veraison. The start of veraison was mid to late January in the two years preceding 2004. In 2004 it was 14 January and in 2005 and 2006 the dates were 12 January and 24 January respectively [10].

246 Thus, when the trial judge said that 'practically' speaking, the time when it was safe and effective to carry out the prescribed burn in the type of forest in DPHB8 was at a time when the grapes were at the veraison to harvest period, he could not, in the light of the findings referred to above, have meant that it was impossible to ever burn outside of the veraison to harvest period. If it were impossible, the trial judge would have said so. A finding that it was impossible ever to burn outside the harvest to veraison period would have been against the weight of the other findings made.

247 That therefore left open the precaution of deferring the burn season by season until it was possible to burn outside of the veraison to harvest period.

248 The question which then followed was whether a reasonable person in the position of the respondent would have taken that precaution. That requires the weighing of the factors in s 5B(2).

249 The trial judge made findings in favour of the appellants regarding the matters referred to in s 5B(1)(a) and (b). As to s 5B(1)(a), the trial judge held that the risk of smoke damage to grapes was foreseeable (and indeed not in issue) [493]. In relation to s 5B(1)(b), the risk of such damage was not insignificant [496]. As to s 5B(2)(b), the trial judge held that 'if harm were to occur ... it would be serious as it could damage the whole grape crop for the year' [502]. The value of the grape crop was over $600,000. These findings were not challenged by the respondents and they were factors which carried considerable weight in favour of the appellants in the weighing of the factors referred to in s 5B(2).

250 The meaning of 'burden' in s 5B(2)(c) is not defined in the CLA. The ordinary meaning of the word is 'that which is carried; a load or borne with difficulty; that part of the cost of manufacture which is not directly productive; to load heavily or to load oppressively': Macquarie Dictionary. Nothing was said in the Ipp Report about the meaning of 'the burden of taking precautions' and the Second Reading Speech and the Explanatory Memorandum say nothing on the topic.

251 In the Ipp Report, in par 7.8, there is a reference to the four components which became s 5B(2), being the 'negligence calculus'. This is a reference to what is sometimes called the 'Shirt calculus': see Wyong Shire Council v Shirt (47) Mason J.

It is then for the tribunal of fact to determine what a reasonable man would do by way of response to the risk. The perception of the reasonable man's response calls for a consideration of the magnitude of the risk and the degree of the probability of its occurrence, along with the expense, difficulty and inconvenience of taking alleviating action and any other conflicting responsibilities which the defendant may have. It is only when these matters are balanced out that the tribunal of fact can confidently assert what is the standard of response to be ascribed to the reasonable man placed in the defendant's position.

253 It will be noted from that passage that the word 'burden' is not used, but in my view, the word 'burden' in s 5B(2)(c) was intended to refer to the 'expense, difficulty and inconvenience' of taking the 'alleviating action', ie the precaution which is proposed. It will often become important where, for example, there is a very low probability of harm and the likely seriousness of the harm is slight but the cost or difficulty of taking the precautions to avoid the risk of harm is substantial. In such circumstances, a point could be reached where a court could conclude that the burden of taking the precaution was not justified given the low probability of harm and the low level of seriousness of the harm. For example, in Department of Housing and Works v Smith [No 2] [2010] WASCA 25; (2010) 41 WAR 217 [119], Buss JA referred to the burden on the appellant in taking the precaution of filling a depression with sand in terms of 'time and cost'.

254 In Shaw v Thomas [2010] NSWCA 169 [60] Macfarlan JA (Beazley & Tobias JJA agreeing) said the precautions involved would only have incurred 'minimal expense'. In Haris v Bulldogs Rugby League Club Ltd [2006] NSWCA 53; [2006] Aust Torts Rep 81-838, the burden of taking the precaution in that case was spoken of in terms of how difficult it would be to implement the precaution.

255 The burden of deferring the burn did not involve any expense, difficulty or inconvenience. This factor therefore carried no weight unless it can be said that there is inconvenience in postponing something which has been planned. If so, the weight would be minimal.

256 The trial judge referred to the social utility of the prescribed burn but did not discuss the concept of 'social utility'. The phrase 'social utility' is not defined in the Act. The word 'social' appears in only one other section of the Act, s 5U, which defines 'policy decision' as including a 'decision based substantially on ... social factors or constraints'. Nothing appeared in the Second Reading Speech or the Explanatory Memorandum about the meaning of the phrase. In the Ipp Report the only reference to 'social utility' is in a footnote on page 103 which reads, 'some activities are more worth taking risks for than others - a plaintiff may be required to submit to a risk for the sake of some greater good that they would not be expected to accept if some lesser interest were at stake. A common situation in which precautions that would normally be thought reasonable need not be taken is where an emergency vehicle is speeding an injured or sick person to hospital'. The expression 'social utility' is likely to take on the compound effect of the ordinary meaning of the two words. 'Utility' means 'usefulness' and 'social' means 'of or relating to the life and relation of human beings in a community': Macquarie Dictionary. Social utility is therefore the usefulness accruing to a community rather than to the benefit of individuals.

257 In some cases judges have felt obliged by the section to consider social utility in circumstances where in cases not governed by the CLA, the social utility of the activity would not have rated a mention. For example, in Bader v Jelic [2011] NSWCA 255, in a case involving an accident where a window with no blind was mistaken for an open door, there was a finding that there was 'some social utility' in having a window unobscured by a blind from an aesthetic point of view. In Haris v Bulldogs Rugby League Club, which involved an injury caused by fireworks at a football stadium, it was held at trial that 'attending football matches' serves 'a useful social purpose' [60].

258 What is useful to the community will sometimes be obvious but sometimes it is not, or it will be a matter of valid debate. There will usually be no evidence led to prove that something is or is not useful to the community.

259 Opinions about what is thought to be of social utility may also change over time. A question at trial was whether there is social utility in carrying out prescribed burns.

260 At the end of this section of my reasons, I observe that the finding of social utility was not challenged. That finding must therefore be accepted. However, in considering whether there is a breach of duty, it is necessary to consider the weight to be given to the social utility of prescribed burns by reason of s 5B(2) of the CLA. In deciding the weight to be given to social utility, the fact that Parliament has legislated to permit the activity does not determine how much weight social utility has to be given.

261 At [500] of the trial judge's reasons, his Honour said:

In terms of the particular factors referred to in s 5B(2), my findings are as follows. As to s 5B(2)(a), the risk of smoke taint to grapes, whilst not insignificant, would not, in my view, be regarded as high, in light of the absence of scientific evidence connecting prescribed burning to smoke taint, and in light of the Department's previous experience of prescribed burning in the winegrowing areas of south-western Australia in the previous 40 years. As to s 5B(2)(b), the nature of the potential harm from the core ignition, were such harm to occur, was, in my view, serious in that smoke taint could well destroy the economic value of the plaintiffs' harvest for that year. With respect to s 5B(2)(c) and (d), those factors bring to account the matters in [406] - [413] to which I have referred in [499] above. In my view, they indicate that the burden of deferring the burn (including the wasted opportunity when opportunities are limited), and the important social utility of carrying it out, outweighed the risk of harm to the plaintiffs' grape crop for a year.

262 This weighing of the competing factors is challenged in this appeal by the appellant. This is clear from par 61 of the appellant's written submissions which reads:

The learned trial judge at [500] of the reasons said, 'the important social utility of carrying it out, outweighed the risk of harm to the plaintiffs' grape crop for a year': reasons [500]. He did not, with respect, consider the matters at [59] and [60] above. He did not, as is often done in the decided cases, give any consideration to the competing social utility of the activity effected.

263 Paragraphs 59 and 60 of the appellant's submissions read:

In any event, there is no social utility whatever in allowing or condoning one neighbour to carry on a dangerous activity on his land and thereby cause damage to the property of the other neighbour (see Hunt v Roads and Traffic Authority of NSW [2010] NSWDC 88 [196], and Sedleigh-Denfield v O'Callaghan [1940] UKHL 2; [1940] AC 880, 903, per Lord Wright). The negative nature of the activity needs to be taken into account, along with the positive (see, for example, the comments of Bryson JA in Hutton v Martin Lewis Shipwrights [1987] NSWSC 1 ... [11].

Further, it has been held in Canada that if a defendant's activities, despite their significant social utility to the public, cause significant physical damage to a plaintiff's land, the plaintiff ought not be obliged to disproportionately bear the cost of those activities: Royal Anne Hotel Co Ltd v Ashcroft (1979) 2 WWR 462.

264 It is therefore necessary to decide this challenge to the trial judge's weighing of the factors set out in s 5B(2). Although the important social utility of prescribed burning is not called into question, the weighing and significance of such social utility, measured against the other factors in s 5B(2), is challenged and called into question. That means it is necessary to decide whether social utility, as found by the trial judge, is of sufficient significance to outweigh the other factors referred to in s 5B(2), all of which tended to suggest that there was a breach of duty.

265 The process of weighing competing factors is a process judges are asked to undertake all the time. They must carry out the process of weighing in accordance with law and not in accordance with personal views about the case. For the reasons which follow, the social utility of prescribed burning should not be given significant weight in determining, under s 5B(2), what precautions a reasonable person would have taken.

266 In the greater part of the 20th century, it was thought beneficial to the community that there should be a large scale clearing and burning of flora in the south-west of the State. The opinion was presumably that this was of social utility because it increased the wealth of the community by increasing agricultural production. This became government policy and was then built into the laws of the State. Thus, land grants were made on condition that land had to be cleared. The point was eventually reached where in many shires within the wheatbelt, less than 5% of the original vegetation remains. In the 1960s, the State government stated that it was its objective that one million acres of land should be cleared each year. Persons who in those days or earlier suggested that large scale clearing was not of social utility because it would lead to increased salinity and degradation of the landscape, were ignored.

267 However, the prevailing opinion about what was of social utility changed radically and rapidly. Now, the opinion is that the clearing of native vegetation is not of social utility. The retention of native forests is now thought to be of social utility. Beginning in the 1970s, organisations were formed calling for the protection of native forests. These had considerable political influence and their existence reflected a changed opinion about the social utility of destroying the remaining uncleared forest areas. The opinion of naysayers of last century about clearing now reflects the prevailing opinion.

268 The reversal of opinion is such that now there is legislation to prevent damage to native vegetation on private land and farmers are now prosecuted for doing what they were obliged to do 50 years ago: see Chief Executive Officer, Department of Environment and Conservation v Szulc [No 2] [2011] WASC 315. The prevailing view now is that there is social utility in preserving the State's remaining forests rather than destroying them.

269 Burning of native forest in national parks would seem to be contrary to that current view. However, successive governments have allowed or encouraged settlements and development in or near State forests. Persons choosing to live near to a State forest must be taken to well know the risk of fire, but many are not by that knowledge deterred from clamouring for the damaging of State forests by prescribed burning in the belief that this will protect them and their property from the risk they assumed. The interests of that group in the community is catered for by the legislation permitting 'prescribed burning'. This results in the planning of the destruction of up to 200,000 hectares of flora per annum (along with associated fauna) in the south-west forest regions: [123] - [124].

270 A person living next door to a large area of privately owned woodland is not able to call for hazard reduction by burning of that property because the owner of the woodland is prohibited by law from doing so. However, persons living next to a State forest are able to and do (as the reasons in this case show) exert political pressure to have the flora burnt. According to the Forest Management Plan, there are 'strongly held views' for prescribed burning. However, there is a recognition that excessive use of fire can be detrimental to forest ecosystems [142]. There are sections of the community against prescribed burning: see the reference in Mr Gillard's email to Mr Walker dated 23 January 2004 which refers to the existence of opposition to prescribed burns [230] and see also the reference to the existence of 'conflicting views' about the impact of burning referred to in the EPA report [151]. The Forest Management Plan ignores those views.

271 Perhaps to overcome the contradiction in prohibiting destruction of flora (and the associated destruction of related fauna) on private land and yet permitting the government to do so on State owned land, an attempt has been made to justify prescribed burning on the basis that it 'optimises the maintenance of forest ecosystem health and vitality' and 'promotes the conservation of biodiversity' [GAB 61]. This suggests that there is some beneficial scientific basis for burning State forest which makes the activity more acceptable.

272 To gain support for this allegedly beneficial aspect of prescribed burning, the Environmental Protection Authority (EPA) was asked for a report on those subjects. The trial judge set out the EPA report at [151]. It responded by stating that the direct impact of prescribed burning on biodiversity 'is not adequately known or understood' and that 'there is insufficient information on the effects of prescribed burning on WA's south-west ecosystems to allow the EPA to come to a conclusive view that optimum outcomes are being achieved'.

273 Notwithstanding that there is no adequate science to support the stated objectives of promoting biodiversity and optimising the maintenance of forest ecosystems, burn prescriptions are still dressed up (as in the burn prescription for DPHB8) as being for, inter alia, the objective of 'protect[ing] and maintain[ing] biological diversity processes and ecological values within the burn area by the application of a low intensity, slow moving prescribed burn that will provide a mosaic of burnt (70-90%) and unburnt (10-30%) patches'. In the absence of any finding by the trial judge on the point, I would not accept that there is any social utility in prescribed burning for the purpose of promoting biodiversity until there was proper scientific evidence that it had that benefit.

274 Another reason for carrying out prescribed burns is said to be for the objective of 'controlling adverse impacts of wildfire on the social, cultural and economic values of land managed by [CALM] and adjoining land'. The burn prescription in this case stated that it was to, inter alia, 'provide a mosaic of burnt (70 - 90%) and unburnt (10 - 30%) patches'.

275 Natural and other man made activities in fact provide a mosaic of burnt and unburnt areas. Thus, in 2001 - 2002, there were 12 wildfires (fires caused by arsonists, accidentally lit or lit by lightning) in the Donnelly District and this burnt out 7,960 hectares. Prescribed burns consumed another 10,200 hectares of flora and its associated fauna [281].

276 In 2002 - 2003, CALM had to manage 656 wildfires across the State which burnt out two million hectares and in the Donnelly District there were 51 wildfires (24 caused by lightning) which burnt more than 5,700 hectares [283]. Thus, wildfires naturally create patches of burnt and unburnt forest. Nevertheless, the assertion is that forest has to be further burnt (by prescribed burning) in order to provide 'strategic' protection from wildfires. This assertion provides support for the public mantra that prescribed burning is beneficial.

277 There is no doubt that if the whole of the State forests were cleared, there would be no risk of wildfire, but that at least is out of the question because the community sees public utility in retaining native forests. So the question which presumably should be asked, is whether there is any scientific support for the view that prescribed burning provides protection from wildfires. Scientific information to support the claim that prescribed burning protection would have to be based upon observation of the outcome in control areas where no prescribed burning was carried out over many years and the outcome in comparable areas where prescribed burning is carried out. No reference is made in the reasons to any such scientific evidence. Scientific support for prescribed burning is not provided by post hoc ergo propter hoc reasoning that there have been no serious bushfires in recent years like those in the Dwellingup region in 1961 or in New South Wales, Canberra or Victoria because prescribed burning began some time ago.

278 There must be a respectable argument open that prescribed burning is damaging to the interests of the community rather than being of social utility. Prescribed burning:

(b) kills and injures wildlife in the areas burnt. This is particularly damaging in the spring during the breeding season for many species;

(c) carries the risk that smoke will be injurious to human health (which the Smoke Management Guidelines seek to minimise at least for the residents of Perth);

(d) carries the risk of smoke damage to property, as this case reveals;

(e) carries the risk of serious damage to property if a prescribed burn escapes, even if care is taken;

(f) carries the risk of death and injury to humans if a prescribed burn escapes, even if care is taken;

(g) may not be proven to provide for the conservation of biodiversity;

(h) may not be proven, rather than merely asserted, to provide protection to property and human life from wildfires.

279 It is likely that the reason why there appears to be community support for prescribed burning is explained largely by the one-sided nature of the press reporting of the subject. Neither the negative aspects of prescribed burning, nor the lack of scientific evidence, is given much attention. However, the calls of persons in favour of more prescribed burning is given great prominence. Even in this case, the evidence revealed that some of the appellants whose property was damaged stated that they generally supported prescribing burning [230], [232]. The appellants did not argue on this appeal that prescribed burns were not of social utility.

280 As there has been no issue raised about the trial judge's finding that there is social utility in prescribed burns [406] - [413], [502], and the appellants have chosen not to challenge that finding, I am obliged to, and do, proceed on the basis that prescribed burning has social utility because it reduces fuel loads. Thus, this factor has to be weighed against the probability of harm and the likely seriousness of the potential harm and the burden of taking precautions.

Appellants' oral submissions that DPHB8 should never be burnt

281 Without abandoning the grounds of appeal, counsel for the appellant in oral submissions contended that the only precaution that could be taken was to not burn DPHB8 at all. This submission must be rejected because the respondents had the statutory power to conduct the burn. The claimed precaution would prevent the exercise of the statutory power. It is impossible to sustain a submission that a common law duty would prevent the performance of a statutory duty (see Sullivan v Moody [2001] HCA 59; (2001) 207 CLR 562 [60]) or a statutory power.

282 The appellants also contended that the duty of care was a duty 'not to allow' smoke from the fire to escape, causing foreseeable damage. That formulation of the duty cannot be accepted. Formulated in that way, the appellants contend that the respondents' duty was not to exercise reasonable care, but to completely eliminate the risk. That submission must be rejected. It is never the case in a claim in negligence, even where a non-delegable duty is owed, that a defendant is required to guarantee that a person or property will not be injured or damaged. Whatever the scope of a duty of care in a particular case, it will always be discharged by the exercise of reasonable care. The general law does not impose a more stringent or onerous burden: Roads and Traffic Authority of New South Wales v Dederer [43]: Sydney Water Corporation v Turano [47]. Even in the case of a non-delegable duty, the duty is to ensure that reasonable care is taken.

283 Counsel for the appellants also submitted that the law should exact in this case 'a degree of diligence so stringent as to amount practically to a guarantee of safety': see Burnie Port Authority v General Jones Pty Ltd (554) quoting what was said by Lord Macmillan in Donoghue v Stevenson [1932] AC 562, 612. The reference in Burnie's case made it clear that such diligence is required where the magnitude of the risk of harm and the seriousness of the potential damage require such diligence: Hackshaw v Shaw [1984] HCA 84; (1984) 155 CLR 614 provides an example.

284 There is merit in the appellants' submission that a high degree of diligence was necessary if the prescribed burn was to be conducted on 31 March 2004 and 1 April 2004. To burn during the veraison to harvest period when the grapes were about to be harvested carried with it not only a risk of harm which the respondent should have foreseen, but a risk of harm which it knew existed. The risk of damage was serious in that it could destroy the appellants' entire grape crop.

285 In those circumstances, the respondents did not demonstrate the required diligence by starting the fire on 31 March 2004. CALM knew that the wind on 31 March was not blowing from the north-east and knew in any event that on 1 April 2004, while the forecast was for north-easterly winds, they were likely to be variable, as proved to be the case. By choosing to burn when it did, CALM fulfilled its wish to press ahead with the prescribed burn, but ignored the risk of harm which came to pass.

The balancing of the factors to be considered as required by s 5B(2) CLA

286 As to s 5B(2)(a), the trial judge found that the probability of harm to the grapes from smoke from the burn of DPHB8 was not insignificant, but would not be regarded as 'high'. This was said to be so because of the 'absence of scientific evidence connecting prescribed burning to smoke taint, and in light of the Department's previous experience of prescribed burning in the winegrowing areas of south-western Australia in the previous 40 years' [500]. In my view, the previous 40 years were not important. The evidence referred to by the trial judge in his reasons was that by 2004, CALM knew that there was a serious risk of smoke damage to grape crops near to the harvest period (so much so that it had deferred the burning of another area because of that risk). The potential harm was very serious because, as the trial judge accepted, smoke taint, if it occurred, could (and as was foreseen, did) damage the whole grape crop for the year.

287 As to s 5B(2)(c), the 'burden' of taking the precaution of deferring the burn was non-existent. A decision to defer the burn involved no cost, no difficulty and no inconvenience. The trial judge erred in concluding that there was any burden in deferring the burn [500].

288 As to s 5B(2)(d), I must accept, in the absence of any issue on the point, that the burn had 'social utility'.

289 Thus, only one factor favoured burning in the veraison to harvest period and that was 'social utility'. In my opinion, 'social utility' (high or not) did not justify taking the not insignificant risk of serious damage causing the loss of the whole of the appellants' crop.

(a) CALM was prepared in the past to defer the burn of DPHB8 from year to year;

(b) CALM had shown a willingness to defer a burn in relation to another area that might have damaged grapes on another vineyard by smoke taint [223];

(c) CALM, through Mr Sneeuwjagt, knew that in the course of a burn over several days, there was a significant chance that the occurrence of swings and changes in wind direction could cause damage if CALM pressed ahead with the prescribed burn in the veraison to harvest period [495];

(d) CALM's attitude was reflected in the briefing note to the Minister. In par 5 it was stated that CALM's position was that it 'will consult neighbours but the commencement and carrying out of prescribed burns will not be delayed at the request of individual wine grape growers. All prescribed burns will be commenced and carried out when the field conditions are suitable for the burn and resources are available'. In short, CALM was determined to press ahead with the prescribed burn, notwithstanding the foreseeable risk of serious damage to the appellants' property;

(e) there was 'no evidence that absent a prescribed burn on 31 March 2004, there was an immediate and substantial risk that a wildfire would break out in the area of DPHB8' [408];

(f) the decision to burn DPHB8 on 31 March 2004 and 1 April 2004 was to burn next door to a vineyard when the grapes were at the greatest risk of smoke damage.

291 In my opinion, the risk of harm if the precaution of deferral was not taken, the seriousness of such harm if the precaution was not taken, and the fact that there was no burden (ie no cost, difficulty or inconvenience other than in planning) in taking the precaution, outweighed the 'social utility' in carrying out the burn. The fact that the respondents had the power by statute to carry out the burn does not detract from that conclusion. Even if it were correct to say that prescribed burning has 'high' social utility, that did not justify taking the foreseeable risk of serious harm of destroying the appellants' grape crop by burning at a time when the risk of harm was at a peak.

292 Section 5W and s 5X of the CLA and s 132 of the CALM Act still have to be considered.

293 The trial judge stated at [460] that both the issues of duty and breach fell to be considered having regard to s 5W of the CLA. His Honour noted that each of the Crown in right of the State of Western Australia, the Department, and the Executive Director as an incorporated body, is a 'public body or officer', referring to s 5U of the CLA and s 3 of the Crown Suits Act 1947 (WA).

294 The trial judge recorded the appellants' submission that s 5W(a), (b) and (c) had no bearing because their case did not involve an allegation of a failure to allocate resources, and the conduct of the burn was not, in any event, limited by the extent of resources available to the Department. The trial judge implicitly accepted those submissions. The trial judge stated that in relation to s 5W(d), the appellants relied on the allegation that the burn was not conducted in accordance with the burn prescription.

The above matters indicate that there was a proper exercise of the Department's functions, and provide grounds for confirming that if, contrary to my conclusions, a duty of care exists, it was not breached: s 5W(d) of the [CLA].

296 The trial judge's reference to the 'above matters' appears to be a reference to [506] where his Honour found that the burn was carried out in accordance with the burn prescription, and in accordance with the 'standards and procedures' applied by CALM in connection with its Master Burn Plan. These included the avoidance of burns on north to north-westerly winds and other findings relevant to wind direction.

297 The appellants submit that s 5W(d) 'does not provide any answer or excuse for the respondents' and that the contents of any internal regulatory document cannot be determinative. They submit that if it were otherwise, then a public body could, by the creation of procedures and standards, 'legislate itself out of liability'.

298 The respondent correctly submits that s 5W(d) does not provide an excuse for a breach of duty. The section provides that evidence that a public body complied with general procedures and applicable standards will be relevant to the issue of the 'proper exercise' of the public body's relevant functions. However, the mere existence of procedures, and compliance with them, does not determine whether any relevant standard of care was breached.

299 There may be cases where the evidence establishes that the procedures have been designed in order to avoid a risk of harm. In those circumstances, proof of compliance with the procedures would allow the court to conclude that there was a 'proper exercise' of the public body's relevant function and that it had not acted negligently. In this case there were no 'standards and procedures' designed to avoid the foreseeable risk of smoke harm to the grapes. The Smoke Management Guidelines provided procedures for avoiding smoke over Perth but made no provision at all for reducing risk of damage to the appellants' vineyards which constituted a 'sensitive' area. As a result the trial judge erred in concluding that the burn was conducted in accordance with internal 'standards and procedures'.

300 The trial judge, having found that there was no duty of care and no breach of duty, then said:

Furthermore, if my conclusions above are erroneous, the decision to burn DPHB8, when it was burnt, was, in essence, a decision based substantially on political or social factors or constraints, and was accordingly a policy decision within the meaning of s 5X of the Civil Liability Act. On either basis upon which the plaintiffs put their case, namely, the deferral of the burn until after harvest or some other unspecified time, or a deferral from 31 March to 1 April, the gravamen of the complaint is that an appreciation of the risk of harm to the plaintiffs' grapes should have led to the burn not being carried out when it was. The question of whether the risk of smoke taint to the grapes, and thus to the economic interests of winegrowers in the region, should be determinative in deciding whether to proceed in accordance with the prescribed burning programme for 2004, was the very matter which the Minister was asked to consider. The plaintiffs' particular request for deferral was also before the Minister. The decision to burn in accordance with the prescribed burning programme irrespective of the risk of damage to grape crops in early 2004, was, in my view, clearly a decision based substantially on political and social factors. This is so having regard both to the nature of the decision, and the circumstances in which it was made. It was made against the broad background of the political history of prescribed burning in this State, and in the context of the particular political sensitivities prevalent at that time, as revealed in the Minister's statements to the House. The operational decision to burn on 31 March 2004 gave effect to the Minister's decision.

Having regard to the matters in [406] - [428], it was not, in my view, a decision so unreasonable that no reasonable public body or officer could have made it. In these circumstances, any fault by the Department in deciding to carry out the burn on 31 March 2004, or in failing to defer the burn, was, in substance, a policy decision in the performance of a public function. Such a policy decision cannot be used to support a finding of fault, by reason of s 5X of the Civil Liability Act. Accordingly, in my view, to make a finding of liability on the basis that the defendants failed to defer the burn, would be contrary to s 5X [510] - [511].

Section 5X is unique to Western Australia. The respondents submit that it was introduced as a result of recommendations at par 10.25 of the Ipp Report which proposed that in a claim for negligently-caused personal injury or death, where the alleged negligence arises out of the exercise or non-exercise of a public function, the functionary should be able to plead the policy defence. In fact, s 5X does not allow for a public authority to plead a 'policy defence'. The section was drafted as a direction to courts that a policy decision 'cannot be used to support a finding that the [public body] was at fault'. This will be particularly important in cases of omission where a plaintiff contends that a decision was made not to exercise a statutory power and the negligence was in making that decision.

301 In this case, the decision made by the respondents was to carry out the prescribed burn. However, this is characterised by the respondents as a decision based on a policy decision because it is said that the decision to light the fire was preceded by a 'policy' decision not to defer the lighting of the fire. This is, in fact, the decision relied on by the appellants to make out its case. The appellants contend that the precaution of deferring was the relevant 'precaution' for the purposes of s 5B(1) and (2). In my opinion, the decision not to take the precaution of deferring the burn was a decision based substantially on social and political factors.

302 However, if the decision taken 'was so unreasonable that no reasonable public body or officer in the defendant's position could have made it', then the decision can be relied on to support a finding of fault. The assessment of whether the decision was unreasonable is similar to the assessment involved in the weighing of the considerations set out in s 5B(2).

303 In this case, no reasonable public body or officer in the respondents' position could have decided to press on with the prescribed burn rather than take the precaution of deferring it to another time in circumstances where:

(a) smoke generated from the prescribed burn, particularly the core ignition burn, generated a substantial intensity of fire and associated high levels of smoke 'not dissimilar' to smoke from a bushfire [495];

(b) where it was known that forecasts as to wind direction provided no guarantee that smoke would be kept off the vines if the burn occurred during the veraison to harvest period;

(c) where the appellants' properties were in close proximity, and indeed right on the boundary of the area to be burnt;

(d) where the respondent knew (not merely ought to have known) that there was a not insignificant likelihood that smoke on grapes in the veraison to harvest period would cause harm;

(e) where the harm, if it occurred, was serious and that it could cause the loss of the whole of the appellants' grape crop;

(f) where it was possible to burn at times outside the veraison to harvest period;

(g) where the respondents had deferred the burn in another area in order to avoid such harm.

304 As a result, the trial judge erred in making a finding that the appellants' reliance on the respondents' decision to defer the burn was contrary to s 5X. As a result, ground 11 should be upheld.

Exemption from liability

The Minister, the Executive Director, any person employed in the Department, a member of the Conservation Commission, Marine Authority or Marine Committee, and any person who performs functions under this Act or the Wildlife Conservation Act 1950 is not personally liable for anything done or omitted to be done by him in good faith in, or in connection with, the performance or purported performance of his functions under this Act or the Wildlife Conservation Act 1950

306 The respondents have filed a notice of contention relying upon s 132 as a further reason why the trial judge's decision should be affirmed.

307 At [441] the trial judge said that 'this is not a case raising for consideration the question of whether the defendants would be liable for acts done by independent contractors'. The trial judge also said that nor was it a case where there was a risk of conflagration if appropriate precautions were not taken, and that fire was not a risk of the conduct, but the very nature and purpose of the conduct. The trial judge held that the outbreak of fire was not the product of negligence, but rather the fire was 'a deliberate strategy, legislatively sanctioned to achieve certain important social goals'.

308 Section 132 is relevant only to the claim against the second respondent, the State of Western Australia. At the hearing of the appeal, there was no dispute that the prescribed burn was lighted and controlled by CALM employees. They are not employees of the first respondent. The first respondent correctly submitted that as a body corporate, it would not be liable for the acts of CALM employees. The trial judge so found [516].

309 The second respondent then submitted, in effect, that if it was to be liable, it would be on the basis of vicarious liability for its employees. However, the second respondent then submitted that s 132 operated to prevent the CALM officers from being personally liable and that in consequence, the second respondent could not be vicariously liable given the immunity of its employees from liability. Reliance was placed on Parker v The Commonwealth [1965] HCA 12; (1965) 112 CLR 295, 301 - 303 and Bell v Western Australia [2004] WASCA 205; [2004] WASCA 205; (2004) 28 WAR 555 [34]. There is debate about the jurisprudential basis of vicarious liability. Either the employer is vicariously liable because the acts and omissions of the employee are imputed to the employer (master tort theory), or because the employer is answerable for the employee's tortious liability (servant tort theory). Under the servant tort theory, the immunity of the employee from an action in tort will mean the employer is not vicariously liable, but under the master tort theory, the employer may be liable even if the employee is immune: see the discussion in The Finance Brokers Supervisory Board v Van Stokkum [2006] WASCA 97 [11] - [19].

310 These cases did not, however, discuss the situation where the defendants owed a non-delegable duty of care. The trial judge, in his discussion about s 132 of the CALM Act, expressed the view that for the reasons given at [441], the case did not involve the existence or otherwise of a non-delegable duty of care as explained and applied in Burnie Port Authority. Reasons given earlier conclude that the trial judge erred in that respect.

311 Insofar as the respondents rely on Bell to support the notice of contention, that decision is distinguishable for the following reasons. A person who takes control of land to bring a dangerous substance onto land owes a non-delegable duty of care to avoid a foreseeable risk of injury or damage to the person or property of another: Burnie (556 - 557). In cases involving a non-delegable duty of care, a breach of that duty by failing to ensure that employees exercise reasonable care involves the employer in primary, not vicarious liability: Stevens v Brodribb Sawmilling Co Pty Ltd [1986] HCA 1; (1986) 160 CLR 16, 29 (Mason J); The Commonwealth v Introvigne [1982] HCA 40; (1982) 150 CLR 258 (Mason J, Gibbs CJ agreeing), 280 (Brennan J). The master tort/servant tort debate which was canvassed in Bell has no relevance in cases where a non-delegable duty has been breached. If the employee is exempt from liability, that will not benefit the employer who breaches a non-delegable duty of care as a result of a failure to ensure that the employee exercises reasonable care.

312 The persons who lit the fire were employees of CALM (this was conceded at the hearing of the appeal). Those persons were employees of the second respondent, the State of Western Australia. Section 132 of the CALM Act protected those CALM employees personally, but that exemption from liability does not exempt the employer, the second respondent, because it breached its personal non-delegable duty to ensure that its servants exercised reasonable care.

313 As a result, the notice of contention should be dismissed.

314 The trial judge did not consider a cause of action in nuisance. The question is whether the statement of claim supported a cause of action in nuisance and if so, whether the trial judge erred in failing to consider such cause of action. If the trial judge did err but there would have been no different outcome, then there will have been no miscarriage of justice.

315 The first question is whether nuisance was pleaded. The appellants pleaded material facts in the statement of claim supporting a cause of action for damages for nuisance. The essence of a claim in nuisance is a pleading of material facts revealing a substantial and unreasonable interference with the beneficial use of the appellants' land. Interference by smoke has supported a cause of action in nuisance. Smoke may constitute an actionable nuisance: see McKell v Rider [1908] HCA 9; (1908) 5 CLR 480; Benning v Wong (315). The respondents did not contend otherwise. The statement of claim pleaded that the smoke caused damage to the appellants' grapes which the parties agreed resulted in a loss of over $600,000 to the appellants.

316 The respondents submitted that the statement of claim did not plead nuisance because the word 'nuisance' or the words 'unreasonable interference' did not appear in the statement of claim. That submission must be rejected. The obligation in the rules is to plead material facts and if the pleaded material facts reveal unreasonable interference and nuisance, then the cause of action, ie the facts supporting the claim for relief (see Do Carmo v Ford Excavations Pty Ltd [1984] HCA 17; (1984) 154 CLR 234), is revealed. The pleaded material facts and the claim for damages revealed a cause of action in nuisance.

Was the nuisance cause of action abandoned?

317 The respondent contended that the trial judge did not consider the cause of action in nuisance because it had been abandoned. Whether this was so has to be determined by reference to the following passage in the transcript.

318 When opening the case, senior counsel for the plaintiffs (appellants) said, 'The claim is brought both in negligence and nuisance' (ts 198).

319 After the case was opened, counsel for the respondents, Mr King, and Mr Viner QC, senior counsel for the appellants, discussed the issue as revealed in the following pages of transcript (ts 200 - 201):

KING, MR: Your Honour, while Mr Casey is being sworn, can I just rise for a moment to address you in relation to one aspect of my learned friend's opening?

MURPHY J: Yes.

KING, MR: There is the suggestion that nuisance as well as negligence is being relied upon by the plaintiffs. Nuisance has not been pleaded and in order to now rely on it as a fresh cause of action, the plaintiffs would need to amend their statement of claim. This, we say, is just too late. It may well be that there are many similarities between nuisance and negligence and the criteria are very similar but in my understanding of the law, [limited] as it may be in that area of nuisance, there is a difference. Different issues would arise. The defendants would need to consider whether or not to call evidence. They would need to amend the defence to deal with the pleading. In these circumstances it just seems to us that it's just too late.

MURPHY J: Yes. Perhaps I will just ask Mr Viner, do you say nuisance is pleaded, Mr Viner?

VINER, MR: It's not explicitly pleaded but our contention would be that it is at the very least implicit in the allegation of negligence and the pleadings of fact that in the sense that the defendants undertook an act which does create a nuisance, namely, lighting a fire from which smoke and ash can be emitted, which if not undertaken with care, which is the negligence component, leads to liability - but I will, if I may, have a look at that and seek to clarify the position, but fundamentally we rely on the pleading as it is.

MURPHY J: Yes. If you need to amend then, of course, you would have to make an application and show the minutes and you would have to swear an affidavit. You have read the High Court's recent decision about amending cases at trial.

VINER, MR: I understand, your Honour, and in making that remark in opening I was intending that it did not alter the fundamental pleading that is there which is based on negligence.

MURPHY J: Yes. Perhaps certainly think about it and speak to Mr King about it but any application to amend is quite a significant thing, these days at least.

VINER, MR: I understand, your Honour, and I don't wish to widen the trial, nor complicate it unnecessarily. Thank you.

320 Subsequently, on the next day, the transcript reveals the following:

VINER, MR: I will not be seeking to amend the pleadings.

MURPHY J: All right, thank you.

VINER, MR: I am quite satisfied of those on the basis of Burnie.

MURPHY J: Yes.

321 At the end of the trial, no written or oral submissions were made by either party about a cause of action in nuisance.

322 The trial judge evidently thought that the cause of action in nuisance was no longer pursued, which is the only explanation for why his reasons did not mention such a cause of action.

323 In my view, the exchange between counsel, and between counsel for the appellants and the trial judge, ended ambiguously. It is possible that senior counsel could be taken as saying that he would not amend the pleadings because he thought that no amendment was necessary (which was correct). On the other hand, it was open to infer that senior counsel thought (incorrectly) that amendment was necessary and that he would not make the amendment and would therefore abandon the asserted claim in nuisance.

324 However, a party cannot be taken to have abandoned a cause of action which is supported by the pleadings unless it is expressly abandoned. The cause of action in nuisance was pleaded, it was not expressly abandoned and therefore the trial judge erred in failing to deal with that cause of action in his reasons for decision. In Briggs v Lunt [No 3] [2011] WASCA 44, a similar point arose. There, the issue concerned a pleaded limitation defence and material facts pleaded in reply to that defence. Although pleaded, there were no submissions made to the trial judge in that case about the limitation defence and, in consequence, the trial judge made the assumption that he did not have to deal with the limitation defence and related pleadings in reply. That was held to be an error: see [117].

325 However, the error will not avail the appellants unless they can show that the case of nuisance would, or may have succeeded.

326 The respondents argue that 'the appellants cannot avoid the application of the CLA by attempting to claim damages for alleged nuisance'. The respondents argue that the provisions of s 5B must be considered, as must the provisions of s 5W and s 5X. This submission is based on the following propositions:

(a) the tort of nuisance is becoming subsumed into the tort of negligence. Reference was made to non-binding statements to that effect in Delaware Mansions Ltd v Westminster City Council [2001] UKHL 55 [29], [31]; Network Rail Infrastructure Ltd v CJ Morris (t/as Soundstar Studio) [2004] EWCA Civ 172 [31] - [38]; Clambake Pty Ltd v Tipperary Projects Pty Ltd [No 3] [2009] WASC 52 [708];

(b) even if the tort of nuisance has not now been subsumed into the tort of negligence, then in the case of an allegation of nuisance against a statutory authority which, in its defence, claims that it was acting in accordance with a statutory scheme, there can be no liability if the authority proves that the nuisance was not the result of negligence on its part: Bankstown City Council v Alamdo Holdings Pty Ltd [2005] HCA 46; (2005) 223 CLR 660 [16], [51]; Benning v Wong (308 - 309)

(c) the CLA applies to causes of action in nuisance because s 5A(2) of the CLA provides that pt 1A extends to a claim for damages for harm caused by the fault of a person even if the damages are sought to be recovered in an action for breach of contract or 'any other action'. The respondents submit that the use of the word 'fault' in s 5B(1) instead of 'negligence' ensures that the provision applies to liability in tort not based on negligence: Department of Housing and Works v Smith [No 2] [78] (Buss JA);

(d) debate during the second reading of the Civil Liability Amendment Bill 2003 (WA) makes it clear that Parliament's intention was to extend the application of the CLA beyond the area of negligence for personal injury: Hansard 8 May 2003, 7,353 - 7,354. The Explanatory Memorandum to the Bill, at cl 5A, states that the proposed pt 1A will apply to 'any claim for personal injury damages whether arising at common law, contract or an action based on a breach of statutory duty (except as provided in s 3A)'. The respondents submit that this should not be seen as otherwise limiting the clear words of the provision or of s 5V(2) and s 5X.

327 As a result of the above points, the respondents submit that the CLA extends to a claim for damages for nuisance.

328 As mentioned earlier, fault is not defined in the CLA. It is not defined in the Interpretation Act 1984 (WA). There seems no doubt that the word 'fault' was used, rather than the word 'negligence', because the latter word may have suggested only negligence in tort. However, the balancing exercise which has to be carried out under s 5B makes it clear that the Act is concerned with fault following a failure to take reasonable precautions against a risk of harm. Causes of action in contract or breach of statutory duty may involve an allegation of a failure to take reasonable precautions against a risk of harm.

329 An action in nuisance does not involve a failure to exercise reasonable care. Nuisance is a cause of action directed at the harm caused, rather than the conduct causing it. Because proof of nuisance does not involve a failure to exercise reasonable care, the CLA does not apply to a cause of action in nuisance.

330 However, if nuisance is established, the statutory authority may escape liability if it is able to establish that it exercised reasonable care. The 'Shirt calculus' would be applied in determining whether there had been negligence, and as stated above, that will be an exercise similar to the exercise carried out by weighing the competing considerations listed in s 5B, but that does not establish that the CLA applies to a cause of action in negligence.

Could the cause of action in nuisance have succeeded?

331 If (contrary to my conclusion) the Act does apply, then for the reasons that I have given earlier, the second respondent would still be found liable because of the breach of the non-delegable duty to ensure that CALM employees took reasonable care.

332 The cases of Manchester Corporation v Farnworth [1930] AC 171 and Edwards v Blue Mountains City Council [1961] NSWR 803; (1961) 78 WN (NSW) 864 suggest that the respondents escape liability if damage was an 'inevitable consequence' of performing the statutory power to conduct the prescribed burn: see also Fleming, JG, The Law of Torts (10th ed) 515 - 517. In Manchester Corporation v Farnworth a farmer took action against the Manchester Corporation for damages on the ground of nuisance as the result of the emission of poisonous fumes from the chimneys of an electrical generating station. The defendant submitted that the generation of electricity pursuant to statutory authority inevitably meant that noxious fumes would be generated. The court held it was not inevitable; the fumes were omitted merely because of the way the operators chose to work the station. The noxious fumes were generated because it was not economically worthwhile recovering the sulphur which went up the chimneys and caused the damage to the plaintiff's property.

333 In this case, damage from smoke was not inevitable in the sense that damage would necessarily occur when a prescribed burn was carried out. It depended upon which way the winds blew and whether or not the atmospheric conditions settled the smoke on the appellants' vineyards or carried it quickly away. If reasonable care had been taken by CALM, the expectation was that there would be no damage. Reasonable care was not taken. The defence to the claim in nuisance was not made out and if the trial judge had dealt with the issue, that is the conclusion he must have reached.

334 The appeal should be allowed, the judgment of the trial judge should be set aside and in lieu there should be judgment for the appellants for $620,000 against the second respondent. The judgment dismissing the claim against the first respondent should not be disturbed.

335 BUSS JA: I agree with McLure P that each of the appeal and the notice of contention should be dismissed.

336 Subject to one qualification, I agree with McLure P's reasons. The qualification is that, as her Honour mentions, it is unnecessary to determine whether the Civil Liability Act 2002 (WA) applies to a nuisance claim against a statutory authority. I prefer not to express a preliminary view on that issue.

JURISDICTION : SUPREME COURT OF WESTERN AUSTRALIA

CITATION : SOUTHERN PROPERTIES (WA) PTY LTD -v- EXECUTIVE DIRECTOR OF THE DEPARTMENT OF CONSERVATION AND LAND MANAGEMENT [2012] WASCA 79 (S)

EXECUTIVE DIRECTOR OF THE DEPARTMENT OF CONSERVATION AND LAND MANAGEMENT

Jurisdiction : SUPREME COURT OF WESTERN AUSTRALIA

Citation : SOUTHERN PROPERTIES (WA) PTY LTD -v- EXECUTIVE DIRECTOR OF THE DEPARTMENT OF CONSERVATION AND LAND MANAGEMENT [No 2] [2010] WASC 45

Costs - Application to remove limits on costs fixed in costs determination - Turns on own facts

Legal Profession Act 2008 (WA), s 280(2)(c)

First Appellants : Mr M M Mony De Kerloy & Mr P J Hannan

Second Appellants : Mr M M Mony De Kerloy & Mr P J Hannan

First Respondent : Mr R M Mitchell SC & Mr B P King

Second Respondent : Mr R M Mitchell SC & Mr B P King

First Respondent : State Solicitor for Western Australia

Second Respondent : State Solicitor for Western Australia

Heartlink Ltd v Jones As Liquidator of HL Diagnostics Pty Ltd (in liq) [2007] WASC 254(S)

Le Brun v Joseph [No 2] [2010] WASCA 52(S)

Southern Properties (WA) Pty Ltd v Executive Director of the Department of Conservation and Land Management [2012] WASCA 79

1 JUDGMENT OF THE COURT: On 4 April 2012 this court ordered that the appeal be dismissed and that the appellants pay the respondents' costs of the appeal to be taxed if not agreed. The respondents also applied for an order that:

The limits contained in the Legal Practitioners (Supreme Court) (Contentious Business) Determination 2010 for Item 23 of the Table to clause 11 be removed.

2 The appellants opposed the application. Orders were made for the filing of written submissions and evidence on the issue and for the application to be determined on the papers.

3 Special costs orders may be made under s 280(2) of the Legal Profession Act 2008 (WA) which relevantly provides:

[I]f a court or judicial officer is of the opinion that the amount of costs allowable in respect of a matter under a costs determination is inadequate because of the unusual difficulty, complexity or importance of the matter, the court or officer may do all or any of the following -

...

(c) remove limits on costs fixed in the determination.

4 Such an application involves two questions: first, whether it is fairly arguable that the taxing officer might properly allow costs at an amount greater than the amount allowable under the relevant legal costs determination; and secondly, whether the inadequacy of the amount allowable under the relevant legal costs determination arises because of the unusual difficulty, complexity or importance of the matter: Heartlink Ltd v Jones As Liquidator of HL Diagnostics Pty Ltd (in liq) [2007] WASC 254(S), approved in Le Brun v Joseph [No 2] [2010] WASCA 52(S) [6]. We are satisfied that the requirements of s 280(2) are met in this case.

5 The issues raised in the appeal are of very significant public interest and importance in this State. The scope and content of the duty of care of a public authority is a complex issue, as reflected in the binding authorities on the subject: Southern Properties (WA) Pty Ltd v Executive Director of the Department of Conservation and Land Management [2012] WASCA 79 [91]. The issue of nuisance was addressed for the first time in the appeal, due in part to confusion generated by those conducting the appellants' case at trial, and raised novel matters of law. There was also an unusually long and difficult pre-hearing conferral process on the issue of whether the appellants alleged any error of fact. The matter was eventually resolved by consent, which resolution resulted in a substitution of the appellants' and respondents' cases. Finally, there is evidence before the court that, based on a broad time based estimate, the costs incurred by or for the respondents very significantly exceed the limits under the costs determination in respect of Item 23.

6 There is no proper basis for the order sought by the appellants that the respondents pay the appellants' costs of the appearance for judgment delivery on 4 April 2012 and the costs of the appellants' written submissions opposing the special costs order. The court ordered written submissions because not all members of the coram who sat on the appeal were present at judgment delivery and a differently constituted coram was sitting to hear other appeals.

The limits contained in the Legal Practitioners (Supreme Court) (Contentious Business) Determination 2010 for Item 23 of the Table to cl 11 be removed.