I once spoke with someone who wanted to see diseases like root rot completely eradicated from forests. While I appreciate his passion for healthy trees, this goal is misguided. While there are some externally introduced exotic diseases of concern, most disease agents found in our forests, such as fungi and bacteria, are natural parts of the forest ecosystem.
Native trees have evolved together with native pathogens, and these pathogens, in turn, have a natural and important role to play in diversifying the physical structure of the forest, eliminating the weakest trees, and increasing the variety of tree species present. Consequently, removing all diseases or pests is not the answer and would result in negative ecological consequences.
Tree health is likely to be most problematic when a tree is in your yard or near your house. A dying tree in a forest of otherwise healthy specimens is typically not a problem.
So what should you do if you have a sick tree? The first thing is to determine whether the tree is actually ailing at all. Some trees, such as western redcedar, as seen in Figure 2, may temporarily appear sick due to normal seasonal dieback (see WSU Extension Fact Sheet FS056E: Seasonal Dieback in Conifer Trees for more information). If the tree is indeed showing symptoms of decline beyond normal seasonal changes, the next step is to determine whether it is a potential hazard (i.e., if it is likely to damage your house or barn, or injure children or animals in the area. Of course, a tree that poses a high risk of injury or property damage requires more immediate attention than a tree that does not carry this risk.
If you are going to meet with a tree expert about a potential problem, having the following information ready will improve your chances of getting an accurate diagnosis.
- Which trees are affected? Just one tree or multiple trees? Which species are affected or unaffected? What is the size or age of the affected tree?