Wood Decay in Living Trees

A Technical Report from The Bartlett Tree Research Laboratories

In urban landscapes, trees are subject to damage that predispose them to wood decay. Damage may result from construction activities that cut roots, vehicular injury, or large branch pruning. Wood decay reduces wood strength which can lead to branch or whole tree failures. The likelihood of failure is greater when other defects, such as codominant stems or trunk lean, are present. Many failures occur during high wind, rain, snow, or ice events when there is an increased load on the tree. When a large tree in an urban area fails, there is a potential for property damage or harm to people. To identify structural tree issues and reduce risk and liability, any tree that is suspected of having significant wood decay should be inspected by a qualified tree risk assessor.