The wind is blowing; rain has turned to ice followed by heavy snow. Suddenly you hear ‘CRASH’ out in the yard. The weight of all that snow coupled with strong winds just broke a huge tree branch. Winter damage to trees is a common problem throughout Nevada. Damaged parts dry out, die or become diseased; ultimately, the whole tree may die. Bad weather is one source of damage, but dry soils, dry winter winds, warm, sunny days and freezing nights without precipitation contribute to winter plant damage too. Low temperatures or prolonged flooding may also damage or kill all or part of a tree’s root system.
Evergreen trees continue to lose moisture during the winter. Water loss is greatest during windy, sunny, mild weather. However, if the ground is frozen below the root zone, water is unavailable to tree roots and even hardy trees can be damaged. Daily heating and freezing accompanied by wind and bright, sunny skies, damages exposed limbs and trunks, most commonly on their south and west sides. Sunburned and dehydrated bark splits, cracks and dies, especially if the tree has thin or young bark.
However, injury symptoms such as twig die back, bud abortion, leaf scorch, leaf drop and stunted growth may not be evident until late spring, often after growth has resumed. Because only part of the root system may be damaged, the plant appears normal until higher temperatures, wind and longer days create a demand for moisture that the roots cannot supply. Although the plants show stress in spring, the damage occurred earlier.
Snow and ice loads can break limbs as I mentioned earlier. The architecture of the plant affects how much damage occurs. Many upright evergreens are permanently separated or “opened-up” at the top of the plant and disfigured by snow. Spreading tree limbs may be temporarily bent down. Sometimes splitting of the main trunk may occur. You can reduce or eliminate ice and snow damage by selectively pruning long, top-heavy, weak, or crossing branches before snow falls. If damage occurs, carefully remove broken branches, cutting back to the next larger branch or to the trunk as soon as weather permits.
Long, vertical cracks can develop in the trunks of trees such as horsechestnut, linden, Norway maple and sycamore that grew vigorously the previous summer. Although these cracks may appear to close when warmer weather arrives, wood fibers may not knit together well and internal decay may occur. Unfortunately, little can be done to prevent or correct this problem.
Keep an eye on your trees this winter. Water them if we have no rain or snow for a month. Prune damage out quickly after occurrence. Stay safe; call a certified arborist for large tree repair and pruning jobs.