Winter in the mountains can have unpredictable weather patterns, with some warm days and others freezing. However, trees can withstand freezing temperatures but may suffer damage as the temperature changes dramatically. Frost cracks naturally happen to trees, and some Kingsport residents may hear a blasting noise like gunshots when winter trees burst their bark. To help explain why our Tri-Cities ISA-certified arborists at Promier Tree share details about the sounds, what causes frost cracks, and if you should be concerned for your tree’s health.
What are frost cracks?
Trees have difficulty enduring expansion caused by water freezing within their wood and contraction caused when the icy water within their wood melts. While removing water from a tree’s cells is an adaptation to survive, the process has the side effect of drying the wood, which may lead to splitting it from within. In addition, the tree’s amount of sap, sugar content, and temperature may result in vertical splits in the trunk, called frost cracks.
Our Bristol ISA-certified arborists explain that while frost cracks won’t kill a tree directly, the marks will be permanent scars on the trunk, which may negatively impact a tree’s value. Frost cracks develop during the late winter and early spring, usually on the tree’s southwest side, where there is a prior injury or a stub on the branch. Cracks begin on winter days when the sun warms bark and interior wood on a tree’s south or west sides, particularly young trees with thin bark.
In the case of winter sunscald, the sun warms the trees, encouraging growth, and as rapid freezing ensues, the internal wood freezes over and dies, leading to a buried trunk, peeling bark, and tree-wide cracks. While healthy trees may also split during winter, defects, prior injuries, or cuts made during pruning are usually the starting points of further splits that continue through winter. Without fully developed bark, young trees may suffer such damage that tree removal is necessary.
Are wounded trees more prone to frost cracks?
In short, yes. Our Johnson City ISA-certified arborists explain that the cambium around a wound location produces callus tissue and a scab, growing out of the wound edge and covering the wound. The quicker a tree can seal an injury, the less chance of cracks later. In the following cold weather, the outer sapwood will freeze and shrink more quickly than the interior sapwood and the heartwood, which causes a strain on the outer sapwood. Woundwood expands and contracts at a different rate from regular sapwood, which may concentrate the tension in wound sites.
If sufficient tension exists, the outer layer of sapwood will crack, usually quite dramatically. The following spring, the splits will start closing when the wood is warmed up and expanded. The tree will again try to cover the injury with woundwood, and it might even succeed in completely sealing off the crack. However, this crack may still open whenever the weather gets cold enough, whether next winter or in several years.
What can I do to protect my tree?
While frost cracks can be dramatic, it’s essential not to panic if you see “new” cracks in the trees. Although cracks can suddenly appear, often they are there for decades, revealing themselves when conditions are right. Trees have evolved means to cope with injuries, and cracks are not necessarily structural hazards. You can try to prevent further cracking by wrapping your tree trunk with a tree blanket any time overnight temperatures reach freezing. Unfortunately, there’s usually nothing we can do for a frost crack, but steps that enhance a tree’s overall viability may help a tree to help itself. If you are worried about your tree, reach out to our ISA-Certified arborists in the Tri-Cities area and request an evaluation of the crack and the tree’s health.
ISA-Certified Arborists in Kingsport, Johnson City, and Bristol, Tennessee
Your trees are adaptable to the natural elements, although they may suffer some damage during the process. Thankfully, trees that suffer a frost crack may continue a healthy life for many years. However, some frost cracks may allow disease and pests to enter the tree and cause further damage. Therefore, it’s crucial to have our ISA-certified arborists in Kingsport examine your trees to ensure good health. If you have questions about frost cracks or want an arborist to visit your property, please call Promier Tree at (423) 872-2988.