Trees can experience different types of health issues. Trees can be attacked by tree pests (such as Asian Longhorned Beetle, Ash Flower Gall, Bronze Birch Borer, Eastern Tent Caterpillar, Fall Webworm, Yellownecked Caterpillar and, of course, Emerald Ash Borer). Trees can also become a victim of various tree diseases. Among the common signs of tree health problems are: discoloration of leaves, holes in the leaves, bark splitting as well as dead branches. Sick trees may also look dull. You should also begin to worry if you see that trees lose their leaves so early or too late. If you have noticed any signs of tree health issues, you need to contact experienced arborists in Toronto as soon as possible.