Tree Evaluation Part 2

Is It Time to Evaluate Your Trees? Pt. 2

By John Voket

In our last segment (Is It Time to Evaluate Your Trees? Pt.1), we introduced risk assessment measures homeowners might consider taking for the trees on their property. In this segment, we’ll dig into the methods and qualifications needed to carry out an assessment.

An arborist certified by the Tree Care Industry Association (TCIA) (TreeCareTips.org) can be beneficial when determining the safety of the trees on your property. The arborist, guided by ANSI A300 standards, will systematically evaluate your trees for risk in three levels.

Level 1: The arborist will view the tree(s) in question, whether in person or through photographs.

Level 2: The arborist will complete a 360-degree, ground-level observation of the tree or trees in question, examining the roots, trunk and crown for structural defects.

Level 3: The arborist will perform advanced diagnostic procedures, which may include extracting samples for lab analysis.

The arborist’s risk assessment method may vary between the following:

1. International Society of Arboriculture (ISA) Tree Hazard Evaluation Method
2. ISA Tree Risk Assessment Best Management Practice (BMP) Method
3. United States Department of Agriculture (USDA) Forest Service Community Tree Risk Evaluation Method

The first method is impractical when assessing one or a few trees on a residential property—in a recent study, it was determined the method “runs the risk of being misused by commercial or consulting arborists who inspect individual trees in a residential setting.”

The same study revealed the third method, though adequate, may sacrifice detail, especially with regard to the tree’s condition and site history.

The second method, according to the study, is most appropriate for residential properties. It develops a list of multiple targets for a single tree, generating a “flexible, yet standardized means of coping with multifaceted assessment scenarios.” The disadvantage to this method, however, is the time needed to complete the assessment, the study found.

Consult with your arborist to determine which method will be suitable to assess the trees on your property. He or she may combine facets of two or three to carry out a comprehensive evaluation.