BLESSINGS IN BLOOM: Protecting Trees from Winter Damage

By Kerry Peetz

The winter tree is a snowflake dressed with grace and bones, a simple miracle to behold on winter’s lonely road.” — Angie Weiland-Crosby.

We’ve had our first wallop of snow, and now is the time to put a protection plan into place for our trees.  Inspecting the tree trunk condition is a great place to start to assess a trees health. Just under the bark lies the vascular system. This system is the lifeline for water, nutrients, and food transport. During winter months physical injury to the bark and trunks of trees can be a concern.

Our Colorado winter weather extremes can cause physical damage to the trunk. Sunscald injury, primarily due to the sun unevenly heating the trunk in late winter, is a perfect example. The sun starts getting stronger in late winter yet nighttime temperatures often drop to below freezing. Smooth or tender bark on the south or southwest side of trunks of younger trees is most vulnerable to damage as bark warmed in the day rapidly cools at night.

Areas of bark will pull away from the wood underneath, damaging the transport system of the tree. Damaged areas may appear sunken, discolored, and may have peeling bark. Fruit trees and maples are among the species most prone to damage. Callused areas may appear on the edge of damaged areas as trees attempt to compartmentalize injury from previous years.

With snowy and icy roads, it’s not uncommon for a car to slide into a tree. This is one way that tree wounds can cause damage to the vascular system. The vascular system includes the bark, the phloem which transports nutrients and plant hormones from the top of the tree to the roots, the cambium which is responsible for growth, and the xylem which transports water along with other nutrients from the roots to the top of the tree. Damage to the tree’s vascular system is permanent and can affect the lifespan of the tree. Wounds can also come from improper pruning, storm damage, and animals. Damage can be minimized from proper pruning techniques and protecting trees from sunscald and animal damage by using barriers or wraps on the tree.

To help avoid sunscald injury, the trunks of younger trees can be wrapped in late fall. Various light-colored tree wraps are available to help reflect excess heat and reduce potential damage. Start wrapping at the bottom and use a shingle effect to allow water to smoothly run off. Secure the wrap at about the first set of branches on the trunk. Keep trees wrapped until late spring.

Wildlife feeding on bark presents another issue for trees. Voles, or field mice, will gnaw on bark near the base of the trunk where excessive material provides cover for them. To protect trees from animal damage, remove vegetation, mulch, and debris from the base of trees. A cylinder of hardware cloth placed around trunks and secured into the soil will keep voles at bay. For rabbits and deer, a taller cylinder of either hardware cloth or poultry wire can be used to provide a barrier to protect bark from their munching damage. Plastic tree trunk guards are also commercially available. Protect trunks higher than the anticipated snow cover depth.

Repellants are another option, especially if wrapping is not practical. Repellents are intended to reduce but not eliminate damage. Always be sure to read and follow repellent directions and reapply, as necessary. Please note that repellent results vary from location to location and from year to year. This year deer may be put off by the repellent and next season it might have little or no effect.

It’s cold weather season. Drive safe, keep warm and protect your beautiful trees!

“And God said, ‘Behold, I have given you every plant yielding seed which is upon the face of all the earth, and every tree with seed in its fruit; you shall have them for food.’” — Gn 1:29.