Your eyes are not deceiving you, winter sunburn can be a real issue for trees in Wyoming. Plants and trees can become sunburned during the winter months just like you. Similar to the sunburn we often experience, sunscald on trees can damage the leaves, stems and trunks exposed to too much strong sunlight. Below is a little information about winter sunscald and what you can do to prevent this from happening to your tree.
Tree sunscald often occurs to younger thin barked trees that have direct southern exposure in the fall or late winter when the weather changes rapidly in our region. When it’s not snowing, Cheyenne winters tend to bring warmer days with strong sun. Tree bark damage primarily occurs during warm days when the sun heats the southern or southeastern bark of the tree. These conditions encourage cells to open up on a young tree trunk. Then the cold, freezing nights shut them back down again. This heating and cooling, expands and contracts the tree’s bark. If this expansion and contraction continues repeatedly it will cause the bark to split, exposing the inner layer of the tree. The damaged area now unprotected makes the tree highly susceptible to disease and if severe enough could ultimately kill your tree.
So how can you prevent sunscald from happening to your tree? Wrap your tree trunk. Wrapping a tree with winter tree wrap paper protects the bark by maintaining a more constant temperature. The wrap absorbs the heat of the sun, and reduces the expansion and contraction of the tree bark.
Apply tree wrapping to prevent the sun-scald of young trees during the first 2-5 years after planting. The best time to wrap a tree is sometime during October and November. The trunks should be wrapped loosely with tree wrap paper, winding it up the trunk like an overlapping candy cane stripe. Tape the end of the tree wrap to itself and never to the tree trunk. Tree wrapping paper can be purchased at almost all local hardware and/or garden stores. Remove the wrapping in the spring (March/April) to allow the tree to grow naturally during the spring and summer, then wrap it again in the fall. An easy way to remember when to apply and remove tree wrapping is the saying “wrap by Thanksgiving and unwrap by Easter”.
Certain tree species including crabapple, ash, honeylocust, maple and linden trees require annual wrapping due to their thin bark. These tree species tend to suffer the most from sunscald damage, even when they are mature. It is recommended to wrap trees until the tree has a naturally protective thick bark; however, if the tree is located in an area where it receives direct southern exposure then winter wrapping is recommended even if the species does not normally require annual wrapping.
Below is a helpful video that can show you how to prepare your tree for our upcoming winter.