Winter can be hard on trees, whether they are evergreen or deciduous. Knowing the common types of winter damage and how to prevent or treat it is one way to ensure your landscape trees survive the cold season. The following guide to two common winter issues can help you understand the different health threats your trees can face when the temperature drops.
Issue #1: Sun Scald
Scald primarily affects the bare trunk of an evergreen or deciduous tree, although it can also affect bare branches. Deciduous trees with thin bark at most at risk. It occurs when the sun warms up the sap underneath the bark when air temperatures are still below freezing. For this reason it is usually seen on the south or east side of a tree. As the sun sets, the sap that rose to the surface refreezes and expands, causing the bark to split. The damage results in a sunken crack or area of dead bark.
Young trees tend to have the thinnest bark, so wrapping their trunks with a tree wrap for the first couple of winters can prevent scald. If scald occurs, you need to trim away the dead bark with a sharp, clean knife, so the remaining life bark can heal over the wound. Wait until spring to trim, to ensure the tree's growth cycle has resumed.
Issue #2: Snow and Wind Damage
Damage from ice and snow is often actually a case of weight damage. The weight of the snow causes branches to break. Deciduous trees rarely suffer from this problem, although a branch may occasionally break from weight. Wind is more likely to cause breakage on a deciduous tree. When this occurs, simply prune back the branch to the nearest healthy branch or the trunk once growth resumes in spring. Pruning out dead, damaged, and crossing branches each spring will also prevent wind damage, since there will be fewer weak branches in the tree.
Evergreens are more prone to snow and ice damage since they keep their leaves and needles, which means they can collect more snow. One way to prevent damage is to prune evergreens so they have a pointed or rounded top. Unlike a flat top, this encourages snow to slide off. If a lot of snow is building up on an evergreen, or if the weight is causing it to split, brush upward on the branches with a broom. Brushing upward knocks off the snow without putting any pressure on the branches. Much like deciduous trees, any broken branches can be trimmed off in late winter or early spring. Annual pruning is also necessary to prevent wind and snow damage. Paying for professional tree trimming can help you prepare your trees for winter.