A Cautionary Tale About Arborists' Reports

The Land and Environment Court has severely criticised the quality of an arborist's report in a judgement dated 12 May 2010.


The case, Proprietors SP 9467 v Motyl and anor [2011] NSWLEC 1120, involved an application under the Trees (Disputes Between Neighbours) Act that sought the removal of three camphor laurel trees. 


In unusually harsh language, Senior Commissioner Moore and Commissioner Fakes declared that the report, prepared by the consultant arborist who had been retained by the owners of the property where the trees were growing, was "not worth having been provided to us".  The Court condemned the report - which it scathingly characterised as a "so-called" report, for including a statement that the Court found to be "patently and demonstrably false" - namely, the arborist's claim that the trees had not caused damage to the palings of a dividing fence.  The Court also excoriated the expert for stating in his report that there was no greater than a 1 in 1 million chance that the trees would present a risk of harm, without providing any basis for that statistical claim.


The Court stated that the deficiencies in the report were reflective of "widespread deficiencies" in the quality of reports that are relied on in cases arising under the Trees Act. The Commissioners therefore determined that the case presented an opportunity for the Court to clarify its expectations concerning the contents of experts' reports - specifically:


1) The report must set out the facts on which the expert relies;
2) Where matters of fact are asserted, appropriate references must be provided;
3) The report must state the assumptions which the expert makes with respect to the facts;
4) The experts' conclusions must be clearly stated.


The moral of this case extends beyond arborists to all expert witnesses who are giving evidence before the Land and Environment Court. 


Any expert would be well-advised to follow the guidelines provided by Commissioner Moore and Fakes. Failure to do so may well result in rejection of the expert's evidence and the prospect that the expert's work product will be characterised in extremely unflattering terms.