How can I tell if my tree is sick or unhealthy?

General signs of an unhealthy or dying tree include decreased or no leaf growth on all or part of the tree during growing season, missing or brittle bark, and fungal growth such as mushrooms on the trunk. Other signs of an unhealthy tree include dropping leaves, poorly-colored foliage, eaten leaves and cracked, split or oozing bark. However, these may also be signs of treatable conditions. A certified arborist can help determine your tree’s health.