Tree Risk Assessment; what you should know, now


​One of the more critical tasks of an arborist or property manager is risk assessment of trees.  It is the responsibility of a tree owner to maintain and manage this important green asset and protecting the safety of others is the highest priority.  Tree Risk Assessment (TRA) is a relatively recent development and it is difficult to find much in the literature regarding the assessment protocol.  Prior to the 80’s and even the early 90’s, little discussion exists on this practice; however, there have been recent developments with drastic improvements in procedure.   Trees have not become more dangerous or a greater risk; the more likely causes of this heightened awareness is perhaps the “litigious society” in which we live, increasing demands from insurance companies and increasing claims against property owners.

In response to increase concern with risk management, a great deal of research and development has been applied to the assessment process.   Specifically, the release of the long awaited standards and best management practices for TRA. Recently approved by the American National Standards Institute (ANSI) is the release of ANSI A300 Part 9, Tree Risk Assessment.  This set of standards focuses on the specific aspect of tree structure assessment.  In addition, the International Society of Arboriculture (ISA) has released a companion publication, Tree Risk Assessment BMP’s as an aid in the interpretation of these professional standards and to help guide TRA process based on current science and technology.
This set of documents is intended to serve as a guide for tree managers and arborists with assessment consistently and accurately and to recommend the proper mitigation to achieve an acceptable level of risk.  What the literature doesn’t do is provide specific tactics or measures for hazard conditions, but provides help in the decision-making process.  Additionally, it is critical for the property manager or owner to consult a qualified arborist in the process. 

The new ANSI standards on TRA and the best management practices provided by the ISA is a great step forward in formalization of this task.  The information can help protect the tree owner and manager by providing consistency in the procedures that emphasizes the needs of the client.  Now, the TRA process is finally moving closer to a standardized technique which will help the arborist evaluate risk and recommend the necessary action to reduce threats in the urban landscape.  If risk assessment is part of the job description a visit to the ISA website to purchase these two publications is highly recommended.

For more great resources view Tree Risk Management.

For publications view FNR Extension Publications or The Education Store, Purdue Extension's resource center.