All You Need To Know About Tree Risk Assessment

Tree Risk Assessment

Arboriculture Australia is pleased to support tree risk assessment methods that arborists have demonstrated to be fit for purpose in various scenarios. The most common risk assessment methods in use in Australia and New Zealand, in order of historical introduction, are:

  • QTRA: Quantified Tree Risk Assessment (Ellison, 2005)

  • TRAQ: Tree Risk Assessment Qualification (Dunster et al., 2013. ISA)

  • VALID: Tree Risk-Benefit Management & Assessment (VALID, 2017)

  • AANZAA-Risk/24: Arboriculture Australia & New Zealand Arboriculture Association Risk methodology (AANZAA, 2024)

QTRA and VALID are quantitative-based methods taught and certified exclusively by their respective businesses. QTRA requires an arboriculture qualification to undertake training and an annual fee to remain on their certification register. VALID does not require an arboriculture qualification. Both QTRA and VALID offer and/or require Apps to operate their systems.

TRAQ is a qualitative method offered by the ISA and requires an arboriculture qualification.  It was developed from the Pacific Northwest Chapter of the International Society of Arboriculture (PNWISA) Tree Risk Assessment Course and Exam (TRACE) (Dunster, 2005) which replaced the Tree Hazard Evaluation Method (Matheny and Clark, 1994). Free, basic training materials from ISA are available with Arboriculture Australia  providing training opportunities. Arborists seeking to gain and maintain TRAQ certification are required to attend courses every five years after initial training.

AANZAA-Risk/24 is a quantitative-based method. It requires an arboriculture qualification appropriate to the Level of assessment. A suite of free-to-download tools and training materials is available via the link below. Please send feedback and enquires to enquiries@trees.org.au . Links and further information are provided below.

(In order of historical introduction:)