What can indicate potential decay in a tree?

The presence of old wounds on the bark is a strong indicator of potential decay in a tree. When a tree sustains a wound, whether from physical damage, disease, or insect activity, it can create an entry point for pathogens and saprotrophic fungi that lead to decay. Over time, these damaged areas may heal, but they can also leave behind internal damage that may not be immediately visible on the exterior. If the tree is not able to compartmentalize and effectively defend against these intrusions, the affected area may begin to decay, compromising the structural integrity of the tree.

While cavities in the trunk can indicate decay, they may also simply be a result of natural growth processes or even wildlife activity without certainty about internal decay. Fruit structures on the branches are signs of healthy growth and reproduction rather than decay. Nesting holes in the crown suggest that birds or other animals are utilizing the tree, which does not directly indicate the presence of decay. Therefore, old wounds represent a more direct and reliable sign of the potential for decay to develop within the tree's structure over time.