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You are here: Home / Urban Forest Connections Webinar / Tree Risk Assessments: Cutting edge science meets practical applications

Tree Risk Assessments: Cutting edge science meets practical applications

A Falled Tree in a Park
Mark Duntemann

Tree Risk Assessments: Cutting edge science meets practical applications
May 10, 2017

Gregory Dahle, West Virginia University
Andrew Koeser, University of Florida Gulf Coast Research & Education Center
Mark Duntemann, Natural Path Forestry

Managing the risks associated with tree failures is an important duty and challenge for urban foresters and arborists. Tree risk assessment remains a very human endeavor as risk ratings are ultimately influenced by an assessor’s experiences, biases, and risk tolerances. While formalized methods for risk assessment have been developed by numerous institutions worldwide, questions remain about whether these approaches offer valid and reproducible results. In this webinar, Gregory Dahle will overview the Tree Risk Assessment protocols and present research that targets understanding how urban trees fail. Andrew Koeser will highlight studies designed to assess which tree and human factors influence risk assessments, and will share the benefits of recent training and qualification efforts. Mark Duntemann will wrap things up by discussing how risk assessments fit into the larger tree risk management framework for developing reasonable risk reduction strategies.


View the webinar podcast »

Tree Risk Assessment (PDF)
Gregory Dahle
Assistant Professor
West Virginia University

Tree Risk Assessment – Perceptions, Reality, and Reliability (PDF)
Andrew Koeser
Assistant Professor
University of Florida Gulf Coast Research & Education Center

Risk Assessment in Urban Settings (PDF)
Mark Duntemann
Owner & Urban Forestry Consultant
Natural Path Urban Forestry


Resources Mentioned in the Webinar

ANSI A300 (Part 9) – 2017 Tree Risk Assessment Standard a. Tree Failure
These standards from the American National Standards Institute (ANSI) represent the industry criteria for performing tree care operations. Part 9 addresses tree risk assessment. Fee required

Best Management Practices - Tree Risk Assessment
The International Association of Arboriculture (ISA) provides a guide for arborists to assess and evaluate tree risk and to recommend measures that achieve an acceptable level of risk. Fee required

ISO 31000 – Risk Management
These standards from the International Organization for Standardization (ISO) can be used by any organization – regardless of size, activity, or sector – to improve its risk management practices.

Impact of assessor on tree risk assessment ratings and prescribed mitigation measures
Published in Urban Forestry & Urban Greening, this articles assesses tree- and assessor-based factors that influence risk ratings, as well as factors that influence mitigation measures.

Tree Biomechanics Literature Review: Dynamics
Published in Aboriculture & Urban Forestry, this article reviews the main literature on tree dynamics, focusing on open-grown trees typically found in urban areas.

US Forest Service Resources

Urban Tree Risk Management: A community guide to program design and implementation
This manual is designed to help communities design, adopt, and implement tree risk management programs, and to train field staff to detect, assess, and correct hazardous defects in urban trees.

How to Recognize Hazardous Defects in Trees
This brochure presents guidelines to assist homeowners and land managers in recognizing hazardous defects in trees and to suggest possible corrective actions. We recommend that corrective actions be undertaken by professional arborists.