All trees pose some level of risk to nearby people, structures and utilities. Typically, this risk is outweighed by the environmental, social, and economic benefits that that trees provide. As trees age or become weakened by factors such as disease, pests, and structural deformities the balance may shift, however, requiring tree owners and managers to decide what level of risk is acceptable and what modifications are needed. Being able to identify the signs and symptoms associated with various defects such as decayed wood, cracks, root problems, weak branch unions, poor tree architecture, and dead tops or branches is necessary to pinpoint structures susceptible to failure.
Tree risk assessment is the systematic process used to identify, analyze, and evaluate tree risk. Understating this systematic process allows a determination to be made on the likelihood of whole or partial tree failure, the consequences of such failure, and the potential targets affected.