Back in January, I wrote a column about the extreme freeze event we experienced in December 2022. As predicted, we saw a number of trees and shrubs that were damaged by this sudden drop in temperatures. Many of our trees and shrubs were not fully acclimated for winter when this temperature drop occurred. Local weather stations recorded temperatures around 75F degrees during the early weeks of December and then single digit temperatures during Christmas weekend that lingered for a few days.
Many of the evergreen plants that were defoliated or experienced branch dieback this winter have mostly recovered from my observations. The few plants that did not recover likely had some other preexisting insect or disease issues and the freeze event accelerated their decline. Unfortunately, some of the victims of this extreme weather event were many local maple trees. We’ve received more calls and emails about maple trees this year than in my entire 20-year career combined.
Typically, maples are considered a very tough, cold hardy tree that is well adapted to freezing weather. There are native maple species that grow as far north as Canada and as far south as Florida. In Georgia, we have a variety of maples that grow well here, including sugar maple, red maple, silver maple, trident maple, and many types of Japanese maples. However, this was not a normal winter.
So, what does freeze damage look like on a maple tree? What we are seeing this year are long, vertical cracks in the bark of maple trees, commonly called “frost cracks.” These cracks may only be a few feet long or in some cases extend the entire length of the tree trunk from the roots to the canopy. Maples have relatively thin bark compared to other trees and can’t handle these extreme fluctuations in temperature, and the bark will split if they are not fully acclimated.
Young maple trees are more susceptible since they have less canopy coverage to protect their stems from rapidly warming due to direct sun exposure. In fact, it’s a common practice in the landscape industry to cover the trunks of newly planted maples trees with a white plastic or “tree wrap” to reflect the sunlight and minimize these temperature fluctuations. Tree wraps are temporary and should be removed once the tree is fully established. Also, pruning too many of the lower branches on young trees creates an environment that makes these trees more vulnerable to this type of winter damage.
Maples of any age that are more exposed with full sun on the southern or western sides are more likely to be affected. Unfortunately, there’s nothing we can do after the damage is done. Some trees may recover with time if other environmental stresses are minimized. Conversely, some trees are already beginning to show symptoms of branch dieback in the upper canopy and may continue to decline over time. Trees that are severely damaged are more susceptible to secondary problems such as wood decay fungi and ambrosia beetles.
I attended a tree conference in Athens, GA recently and many conversations with my colleagues revolved around the fact that maybe we shouldn’t be planting maple trees as much in Georgia, especially in more open, exposed urban areas. The worst place to plant a maple tree is in the middle of a parking lot or along a roadside with a southern exposure. Maples are best adapted to forest edges with some shelter or protection from extreme temperature fluctuations on the southern/western sides of the tree.
You will want to watch damaged maple trees closely for signs of insect damage or disease as time progresses. Do not paint or cover the injured stems. In a few years, if the tree survives, it should begin to form callus tissue or a thickened scar around the split bark. Avoid fertilizing trees in late fall, as that encourages rapid, new growth that is more susceptible to splitting. Thin barked trees such as maple and cherry are more prone to frost cracking, which makes site selection important when planting these species. Keep affected trees watered during the summer by watering deeply, once a week during extended dry periods.
Paul Pugliese is the Extension Coordinator and Agricultural & Natural Resources Agent for Bartow County Cooperative Extension, a partnership of The University of Georgia, The U.S. Department of Agriculture, and Bartow County. For more information and free farm, lawn, or garden publications, call (770) 387-5142 or visit our local website at extension.uga.edu/bartow.
