News : Repairing damaged trees: What to prune, and when

In extreme storms there are no preventative measures that can reduce tree damage. But many of our trees can be repaired and others have pre-existing weaknesses that can be corrected to reduce storm damage.

Storm damage evaluation
The first step is to visually assess the damage to your trees. Look up for broken or hanging branches (commonly called hangers). Do they look as though they will fall when the next wind blows? Look for cracks in the branches or trunks; this may suggest serious structural damage. In general, trees with large broken tops and/or trees that have lost more than 60 percent of their branches should be considered for removal. Finally, examine the roots by looking at your tree from a distance to determine if the tree is leaning. With high winds it is very possible that some trees may sustain root damage. This is often indicated by the appearance of bumps or raised mounds in the ground that are caused by breaking or moving roots.

Who should do the work?
As long as you are not “Tim (the Toolman) Taylor,” small and young trees that have sustained minor damage can be repaired by you. With a pair of sharp hand pruners, a small pruning saw and even a small chain saw, you can prune broken limbs and branches yourself. Be safety-minded by wearing hard-toed shoes, hard hat, eye protection, gloves, and if working with a chainsaw, invest in a set of protective chaps.

Focus on removing branches that are cracked or broken and minimize the removal of healthy, undamaged branches. It is critical to leave as much live material on a damaged tree as possible. Do not flush cut or leave stubs. Remove branches by first reducing the weight to avoid bark tearing, then make your final cut just outside the branch collar. There is no need for pruning paints and dressings; they are no longer recommended.

When working with large trees, resist the temptation to climb on a ladder. Too many people forget the dangers in being 15-20+ feet off the ground. When large trees need work, seek the services of a professional arborist to do the work safely. But do not assume they know what you want done with your trees. Communicate to them what you want done. In all cases, do not have your tree topped! “Topping” is basically the indiscriminate removal of branches with no consideration for proper cuts that promote good tree response.

Can we prevent damage?
Pruning trees when they are young and small is one of the most important things that you can do to prevent or reduce future storm damage. Pruning young trees develops good branch structure and tree strength, but limit pruning of newly planted trees to the removal of dead and broken branches. Begin pruning of trees one to three years after planting and continue through the first 15-20 years of the tree’s life.

Concentrate your pruning efforts during the early years on the removal of crossing, rubbing, broken, diseased, weak-angled branched, and double leaders in the upper portion of the tree. Removing these structural problems when the branches are small reduces the size of wounds created and allows for quicker wound sealing. When developing good tree structure, consider the amount of space between permanent branches. Space permanent branches along the main stem 15-20 inches apart.

When should you prune?
Remove dead and broken branches at any time. However, when conducting preventative pruning, the most favorable time is mid-winter to early spring before the buds begin to open. Oaks should not be pruned from the end of March to August to avoid the disease oak wilt.