It is surprising that all of the Australian Standards that have directly related to arboriculture have been controversial in one way or another. The proposed standards on Amenity Tree Value (AS Various Drafts) hold the record for Standards Australia for an unresolved standard at nearly 30 years, before it was abandoned. The Pruning of Amenity Trees standard (AS 4373-2007), which is now widely used and accepted took ages to develop and was subject to a very large number of comments initially. Fortunately, its review was a much easier process. The standard on Tree stock for Landscape Use (AS 2303-2015) was finally adopted after decades of debate. Now the standard on the Protection of Trees on Development Sites (AS 4970-2009) is the subject of controversy, debate and mis-use. It was to be expected!

The expectation that the arboriculture industry places on Australian Standards is that they will be perfect and apply to all and every situation. Such an expectation is simply unrealistic and the development of a perfect standard is impossible. When you are dealing with living organisms such as trees, there will be variation, unexpected situations and the unique. This is certainly the case with the standard relating to trees and development sites. The standard recognises this situation and, unlike most standards, incorporates a level of flexibility in the interpretation and use of the standard, which demands a high level of professional competence from the arborists who use it.

This is really where the controversy related to the standard arises. The standard is to be used by well-qualified arborists (at least certificate level 4) who interpret and use the standard based on data that have been collected on-site to inform and justify decisions in relation to protecting the tree. In taking this approach, which was developed with the best interests of the tree in mind, the standard is open to misuse by the incompetent and unscrupulous. Such mis-use and deliberate misinterpretation will probably only be resolved finally through the Australian legal system – probably when things have gone badly wrong!

The flexibility that the standard allows recognises the uniqueness of the individual amenity tree in it specific location. However, the standard requires of the consulting arborist that they assess the tree in its situation and gather sufficient data in relation to the tree’s root system, canopy and general condition to make informed decisions that protect the tree on the particular development site. In this sense, the standard gives the arborist license to make decisions that take into account the particulars of the development process, but only to the extent that they do not compromise the protection of the specimen.

Dr Greg Moore OAM

Senior Research Associate of Burnley College, University of Melbourne Greg was Principal of Burnley from 1988 to 2007 and Head of the School of Resource Management at

the University from 2002 to 2007.

With a general interest in horticultural plant science, revegetation and ecology, Greg is particularly interested in arboriculture. He was inaugural president of the International Society of Arboriculture, Australian Chapter, and has been a member of the National Trust’s Register of Significant Trees since 1988 and chair since 1996. He has served the Board of Greening Australia (Victoria) 1988-2012 and was a trustee of Trust for Nature, 2009-17. He has chaired TREENET since 2005 and is on the board of Sustainable Gardening Australia. He has written two books, contributed to five others and has published over 165 scientific papers and articles. He was awarded an OAM in 2017 for services to the environment, particularly arboriculture.