Safety in Numbers – The Value in Tree Risk Assessment & Management — International Society of Arboriculture

Safety in Numbers – The Value in Tree Risk Assessment & Management (#16)

David Evans

Quantified Tree Risk Assessment (QTRA) has recently undergone the first major development since its launch in 2005.  The most significant advance has been the embedding of Monte Carlo simulations so the uncertainty that is ever-present when assessing tree risk is embraced and accounted for.  Furthermore, ‘Probability of Failure’ benchmarking, and calibration exercises during training in the field, has significantly improved consistency with risk assessors.  This presentation will give an overview of QTRA v5 developments and look at the substantial advantages it gives to the tree risk assessor, and the considerable benefits it provides for the tree risk manager.  A case study of North Somerset Council (NSC), which adopted QTRA principles as policy, will illustrate how they have been able to undertake cost-effective tree risk management during times of severe financial austerity in the UK.  Not only have NSC met their legal duty of care obligations, but done so whilst maximising the benefits from their tree assets, and achieved this at a reduction of 50% in the costs of tree risk assessments and risk mitigation tree work.