Repair of snow and ice damage to trees

Excessive amounts of snow and ice can cause injury to farmstead trees and shrubs. Unfortunately, before storms occur little can be done to prevent damage. Often, however, with proper care damaged trees can be restored.

Several tree species are generally more susceptible to ice and snow damage than others. Deciduous trees with soft brittle wood such as Manitoba maple, Siberian elm, poplar, birch and willow may be seriously damaged by ice and snow. Coniferous trees are not as prone to damage, however, multi-stemmed low growing evergreens such as junipers tend to break or spread under a load of snow.

When large quantities of snow and ice are present on tree limbs, several steps can be taken to prevent damage. As ice coatings may increase the weight of a branch up to 40 times, improper removal of ice or snow often increases damage. Ice laden branches should be propped up with suitable materials and knocking ice off branches where breakage may occur should be avoided. Snow may be gently brushed away if it has not frozen to the branches.

Once damage has occurred trees should be examined carefully to determine the extent of the injury. If damage is not too extensive and the tree is worth saving, proper pruning and/or repair of affected trees should be employed. If damage is extensive the tree should be removed and replaced with an appropriate specie. When large branches or the entire tree is damaged severely enough to endanger human life and property, the pruning should be done as quickly as possible, otherwise pruning and/or repair can be delayed until spring.

When breakage has occurred but the branch has not split to any great extent, remedial action can be taken to avoid further splitting and the entry of moisture and disease organisms. The split crotch can be brought together and retained in position by a cable extending from the trunk to the limb. To further reinforce the repair, bolts with washers, should be inserted through the split area every six to eight inches down the length of the split.

Severely damaged branches should be pruned back to the next lower crotch in early spring (Figure 1). Trees which bleed readily (birch, maple) should not be pruned until leaves appear. It is important to make a smooth cut in sound wood so proper healing can be initiated. All cuts should be made flush to the trunk, although retention of a small lip as illustrated in Figure 1 (E), will speed healing. Never leave a stub as they lead to proliferation of water sprouts or suckers. When the main stem or leader has been damaged, it should be cut off flush with a smaller branch that is growing in the desired direction. Following pruning, saw cuts should be treated, and although not essential, paring the ragged surface of a saw cut will accelerate healing. Generally, healing will occur quicker if no tree wound dressing is applied,however, if disease and insects are a problem in the area, all cuts with diameters of one inch or more should be sealed by painting with a tree wound compound. There is some evidence that application of a complete fertilizer in late April or May will help stimulate new growth and speed recovery.

If ice and snow damage is a common occurrence in your area, it may be worth considering some preventative pruning of high value specimen trees. Branches with weak crotches or those which are weakened by disease or insects should be removed prior to the winter months.

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