Sunscald - What It Is and Why It Happens

It’s officially winter now, and you probably think you’re done with yard work for a while, but if you want to spare your trees from the harsh winter ahead, there are a few steps you need to take. In the next two posts, we will discuss sunscald – what it is, why it happens, and what can be done about it.

When you hear of trees falling victim to sunscald, your first instinct probably isn’t to think of winter, but it should be! While it may sound like a problem that occurs during a dry, scorching summer, sunscald is actually a winter issue.

Sunscald occurs when the sun warms up the south/southwest sides of young, thin-barked trees, such as Maple, Cherry, Honey Locust, Crabapple, Linden, Mountain Ash, and Willow. The heat causes the cells in that part of the tree to become active and think spring has arrived. But when night falls, so does the temperature, which causes the active cells to freeze and die. This results in areas of the tree that become discolored and looks flattened or sunken, before cracking and sloughing off (click to enlarge picture, for detail). The tree, in its weakened state, also becomes more susceptible to harmful organisms, such as fungi and insects.

Check back soon to find out how to prevent sunscald on your trees!