Questioni have a shamel ash that is about 8 years old. In the last few years the bark on the trunk has turned black and is peeling off. It also is loosing some branches but only on one side. I checked the branch for any holes for borers but it looked fine, any ideas what is causing this? we have another one nearby and it took a pretty good hit with the frost but the tree bark is not black or peeling off. any suggestions?
AnswerSounds like Sunscsld.
Sunscald is another form of winter injury that can cause cracks and splits. Sunscald occurs when cells in the living tissue beneath the bark thaw out on sunny days. This occurs mainly on the south or west side of trunks and branches. These cells rupture when they re-freeze at night. The tree is injured when enough cells in a given area rupture. You'll notice the injury the following spring as a discolored, sunken area. Fungus infections often invade trees via sunscald injuries. Young, thin-barked trees are most susceptible to sunscald injury. These include maple, honey locust, linden, and mountain ash. Heavy pruning on neglected trees exposes sections of bark that have been protected from the sun's direct rays for years, predisposing them to sunscald injury.
You can reduce or eliminate sunscald injury on young trees by wrapping the trunks each fall with tree wrap paper. Do this every year until the bark begins to roughen. This may take only a few years on some trees, but more years on others. Prune trees that haven't been pruned for years in stages, not all at once. This will help prevent sunscald.
I would spray the area with an insecticide called Merit to prevent borers from entering the trunk. And fertilize the tree with 10-10-10 fertilizer at the rate of 1 lb per inch of trunk diameter scattered around the tree and watered in good. This will increase the health of the tree and allow the tree to better stave off any insect or fungi.
