Screen tree risk using the ISA TRAQ methodology. Rate failure likelihood, impact likelihood and consequence severity to get a risk rating and recommended action.
TRAQ (Tree Risk Assessment Qualification) is the International Society of Arboriculture's standardised method for assessing tree failure risk. It evaluates three factors: likelihood of failure, likelihood of impact (target in strike zone), and consequences of failure. These combine into a risk rating from Low to Extreme.
A tree reaches High risk when it has significant structural defects, is near a frequently occupied target (e.g. playground, office window), and failure would cause serious injury. Extreme risk typically means imminent failure, a continuously occupied target and severe consequences — requiring immediate action.
This calculator is a screening tool based on ISA TRAQ principles. A formal tree risk assessment for council consent, insurance or legal purposes must be conducted by a certified arborist using the full TRAQ methodology. Always document the assessor name, date, tree ID and site conditions in a formal report.