Application of the precautionary principle
65Preston CJ in Telstra Corporation considers in detail, one of the key tenants of ESD - the precautionary principle. The application of the principle and therefore the need to take precautionary measures requires two conditions to be satisfied: a threat of serious or irreversible environmental damage, and scientific uncertainty of the damage [128].
66At [130], threats to be considered may be direct, indirect, incremental, cumulative, and or the result of other actions. At [131] factors to be considered in assessing the seriousness of a threat are listed; at [132]-[135] the assessment process requires appropriate scientific input. At [138] Preston CJ states: The precautionary principle does not apply, and precautionary measures cannot be taken, to regulate a threat of negligible environmental damage...
67In regards to the applicability of the first test to the matter before me, while it may be argued by some that the removal of one dead tree with perhaps only one hollow is negligible or at least not serious or irreversible environmental damage, it could also be argued that it is a serious threat when the cumulative impacts are considered. The impact of urban development on remnant bushland is often described as 'death by a thousand cuts'. Often, most at risk are large old trees that may be perceived as posing a risk to safety. As hollow formation takes many years, it is often only in these older trees that hollows are found. The listing of 'loss of hollow-bearing trees' and 'removal of dead wood and dead trees' as key threatening processes under the TSC Act, significantly elevates the importance of retaining dead trees with hollows wherever possible. The many references in SSDCP to the need to retain hollow-bearing trees indicate to me that council considers the removal of such trees to be a serious threat to local biodiversity and to the success of its Greenweb strategy.
68Therefore, I find that there is a threat of serious environmental harm and thus the second test of 'full scientific certainty' must be considered.
69Returning to Telstra, "a lack of full scientific certainty" is considered at [140] - [149]. Questions to be considered include: the sufficiency of any evidence; the level of uncertainty - perhaps due to methodology; the potential to reduce the uncertainty within a reasonable time frame; and the level of certainty required in the context of the magnitude of the environmental damage.
70In the matter before me, it has to be said that neither party has established, with any modicum of certainty, that the hollow is used by native fauna, or indeed if it is capable of being used, as no aerial inspections have been undertaken nor have any targeted surveys been carried out. Similarly, it has not been adequately established if there are any other hollows present that cannot be observed from the ground. The applicant assumes that the trunk has a high proportion of sound wood that would limit the formation of future hollows, but there is no evidence of this.
71While there are reports of incidental sightings of birds and a perhaps a possum, this evidence cannot be verified and therefore cannot be relied on. The applicant proposes the installation of nest boxes in other trees. As each species that nests in hollows has very specific spatial requirements, the appropriate selection and positioning of nest boxes requires some specialist knowledge as to the species likely to be displaced from the tree to be removed. While some assumptions may be made from desktop searches of wildlife databases, the spatial scale of those resources may be less applicable to local areas of bushland and may be limited to listed species and not the broader range of fauna that may require protection now to avoid eventual listing.
72On this basis, there is clearly insufficient evidence to determine whether the removal of the tree will result in the loss of current habitat for an unknown number of species. In this regard I find Mr Fraser's conclusions (given at [17]) to be focussed on 'significant' habitat and 'significant' species rather than the broader consideration of 'habitat'. Because of the methodology, that is, a limited ground level inspection, the level of uncertainty is high. I consider that the potential to reduce the level of uncertainty within a reasonable time frame exists if the dangerous limbs are removed and the targeted survey recommended by the parties' ecologists is implemented. The results of the survey would not only inform a decision to keep or remove the trunk but, anticipating that it may eventually be removed on safety grounds, it would also inform the appropriate choice and location of nest boxes.
73As I find that the two conditions or threshold tests are satisfied, the precautionary principle is activated.
74Taking the Telstra decision further, at [150] - [155], Preston CJ considers "shifting of the burden of proof". At [150] he states in part,
...A decision-maker must assume that the threat of serious or irreversible damage is no longer uncertain but is a reality. The burden of showing that this threat does not in fact exist or is negligible effectively reverts to the proponent of the economic or other development plan, programme or project.
75The basis for this, at [151] is to prevent environmental damage rather than treat it and therefore to err on the side of caution.
76In this matter I find that the council made the order requiring the retention of the trunk and the hollow on the basis that hollows provide habitat and that the removal of the trunk was not necessary on safety grounds. In doing so, it could argued that the council considered the removal of the hollow-bearing portion of the tree to be a serious threat to the local environment. In the making of the order, council applied cl 56(5) of SSLEP and the assessment principles in cl 4.k - Special Considerations for Dead Trees which Contain Habitat in SSDCP. In the circumstances of this appeal against the emergency order, the burden of proof that the threat of environmental harm is negligible falls to the applicants. In my view, the applicants have not established the level of threat, and the precautionary measure they propose (the installation of nest boxes) is not based on any specific knowledge. However, as the threat has been established, the applicants will be required to organise and pay for the ecological surveys recommended by the parties' ecologists.
77At [162] in Telstra Preston CJ states in part: Prudence would also suggest that some margin of error should be retained until all of the consequences of the decision to proceed with the development...are known. At [167], In applying the precautionary principle, measures should be adopted that are proportionate to the potential threats. A reasonable balance must be struck between the stringency of the precautionary measures, which may have associated costs, such as financial...., and the seriousness and irreversibility of the potential threat..
78In this matter, the applicants argue that the survey period of 12 months is too long in the circumstances of an emergency order. The primary reason for the order is to remove the risk of damage or injury to an adjoining property posed by falling branches. Regardless of whether the trunk is removed at the same time, the branches have to be removed. The applicants made no submissions concerning economic hardship or the practicality or otherwise of undertaking the order; it is agreed that the trunk is stable. Therefore it seems to me that there is no reason to shorten the survey period. Given the possible transient use of the hollow, and the widely accepted fact that most fauna are more active in spring and summer, in my view, the 12 month survey period is the minimum period required to determine the future of the trunk and to inform any decisions on the installation of alternative habitat. I consider it to be proportionate to the potential threat and consistent with the objective in cl 4.e.1 of SSDCP in ensuring the tree is managed in a way that reduces risk to life and property.
79With respect to council's submission that a condition should be imposed requiring the planting and maintenance of two replacement Angophora costata , there is no evidence before me, such as the composition of remnant bushland on the site, to convince me that this is necessary at this stage. This may be a condition that council imposes when the tree is eventually removed.