I provide Tree Managers and Owners with the Knowledge to Increase the value of their trees and urban forests while minimizing the risks and the costs.
his study consisted of a basic Level II risk assessment of 102 trees growing in the vicinity of a newly built bike trail beside a section of Calleguas Creek in Southern, California. 54 of the trees are outside the county’s Watershed Protection District right-of-way the other 48 are in the right-of-way. All are close enough to have been affected by construction of the new trail in the opinion of this arborist.
The study considered the likelihood of these 102 trees or their branches falling in the next three years. I looked at the things those trunks or branches might hit if they fell, called “targets” in the language of risk assessment. Targets I considered were homes, people in backyards, landscaping in backyards, property line fences, the trail and its fence and people moving along the trail.
The trees were sorted into categories based on the severity of the consequences and likelihood of them failing. Three trees 9, 10 and 21 have obvious structural root loss, they are 80 feet tall with massive trunks and they are 45 feet from homes. . . The tree risk assessment standard calls this combination “unlikely” or at worst “somewhat likely” and despite the severity of the consequences, an arborist could rate these trees a moderate or even low risk. I chose to label them a high risk in this study because of the cases illustrated below: