TRAQ (Tree Risk Assessment Qualification) is a tree risk management methodology created and endorsed by The International Society of Arboriculture which was designed to provide a systematic process for assessing tree risk. Within this methodology the trees likelihood of failure is assessed in relation to its likelihood of impacting a target within its fall zone (see likelihood matrix below). This likelihood rating is then measured against the consequence of the failure impacting a target to finally calculate a risk rating (see risk matrix below). This target-based approach is a powerful tool when prioritising tree inspections in the urban environment, especially for inspectors responsible for large tree populations were visiting every tree is impossible. However, as the likelihood of failure is subjective, the risk assessment can be easily manipulated by the inspecting arborist to calculate risk ratings which supports his or her proclivities regarding tree management.
Managing Tree Risk 101 