State of mind
36 The most controversial aspect of the case is the defendant's state of mind. The defendant deliberately poisoned the trees. However, he has consistently maintained, including under cross-examination, that when he did so he was unaware that it was unlawful to do so without development consent. Following commencement of the council's investigation, the defendant deliberately filled with mud the holes he had bored in the trees and covered over the mud with bark. Again, he has consistently maintained, including in cross-examination, that he did so, not in order to conceal the poisoning, but because an unidentified tree removal contractor whom his son had arranged to visit the property, apparently after the council investigation commenced, told him to do so. He said that he did not know the reason but, as I understand it, simply did what he was told.
37 Having regard to the defendant's limited mental capacity, work experience and the psychological and psychiatric evidence and my assessment of him when giving evidence, I am prepared to give him the benefit of the doubt by concluding that he did not know when he poisoned the trees that he needed development consent to do so. However, I have concluded, after also taking into account the chronology of events, that he covered up the holes with the intention of concealing from the council investigator that he had poisoned the trees, and that by that time he had acquired an understanding that his conduct in poisoning the trees was unlawful. He told the council investigator in his phone call of 1 February 2008 that the trees were dead without disclosing that he had poisoned them. Shortly thereafter he went to considerable lengths to conceal the holes that he had made in the trees by placing mud in them and covering them with bark. Assuming that an unidentified tree removal person had told him to do so, I am unable to accept that his "concrete" thinking was such that he did not understand that he was deliberately attempting to conceal what he had done from the investigating council officer. On the contrary, I am satisfied that was his intention, and it was because he had acquired an understanding that the poisoning was unlawful
Deterrence
38 The penalty in this case does not need to serve the function of a specific deterrent. It appears highly unlikely that the defendant will re-offend. However, there is a need for the penalty to serve as an effective general deterrent. The prosecutor submits, and I accept, that the poisoning of trees is offensive conduct which causes much disquiet in the community and is an offence which is typically difficult to detect. The defendant submits, and I accept, that the purpose of general deterrence is to deter those engaged in similar activities from committing like offences and that in the present case such persons are represented by individual home owners determining whether development consent should be obtained before removing trees, rather than developers and builders.