Assessing wound-induced response growth in two common urban tree species

This study investigates the effect of trunk injury severity on initial tree strength loss, and how trees respond to those injuries through adaptive growth.

Injury was made on the tree trunk. We will be monitoring tree growth response and spread of decay over several years. We will also be measuring how the injury and subsequent response effects trunk strength and stiffness.


Healthy trees are able to alter the amount and physical qualities of new wood produced in order to compensate for forces placed on branches, trunks, or roots. Current industry Best Management Practices and Tree Risk Assessment Qualification (TRAQ) training materials highlight the importance of response growth as a potential indicator of both tree weakness and compensation for that weakness. Despite an emphasis placed on this latter role, both references acknowledge that the industry has few guidelines for evaluating the impact response growth in compensating for structural defects such as injury and decay. This project builds on past research, assessing trunk strength for southern magnolia (Magnolia grandiflora) and pin oak (Quercus palustris) trees intentionally wounded at various levels of severity. Trees will be left to respond to the intentional wounding inflicted upon them. The progression of decay, wound response, and their impact on mechanical strength is being measured regularly over a 5-year period. Results will be used to better inform risk assessments which follow the ISA Tree Risk BMP/Tree Risk Assessment Qualification recommendations.

Funding Sources

TREE Fund Hyland Johns Grant

Project Status