Assessing Storm Damaged Trees
Storm and Winter Damaged Trees
Should These Trees Be Saved?
Trees and shrubs have an amazing ability to recover from storm damage or winter damage. Often, what at first glance looks devastating may not be fatal to the tree. Once the tree is dormant, it can withstand more physical damage than when it is actively growing. There are many questions you must ask before you decide the fate of the damaged tree.
To assess tree damage, homeowners should ask the following questions:
1. Before the storm damaged the tree, was the tree basically healthy, vigorous and not creating a hazard?
2. Are major limbs broken? Naturally, the larger the broken limb, the harder it becomes for the tree to recover. If a majority of the main branches are gone, the tree may have little chance of surviving and will most likely be very unhealthy, even if it does survive.
3. Has the main leader (upper trunk) been lost? This is a judgment call. If the top is broken out on most single stemmed tree species, the result is usually not very pleasing aesthetically. Of course, the remaining portion of the tree has to have a reasonable amount of live crown (foliage) area to sustain the tree. Usually a tree in this condition will develop a new leader from small branches just below the broken area. However, without some selective pruning, this “new leader” growth is generally weak, unappealing and can lead to future problems. If the trunk diameter at the point of the break is larger than one-third of the ground-line diameter, the tree probably should be removed.
4. Is at least 50 percent of the tree’s crown (branches and leaves) still intact? This is a good rule of thumb on tree survivability. A tree with less than half of its branches remaining may not be able to produce enough foliage to nourish the tree.
5. How big are the wounds where branches have been broken or bark has been damaged? Naturally, the larger the wound relative to limb size, the less likely it is to heal. A two- to three-inch wound on a 12-inch diameter limb (16-25 percent) will seal over with new bark within a couple of years.
6. Are there remaining branches that can form a new branch structure? The remaining branches will grow more vigorously as the tree tries to replace the lost foliage. Look to see if branches are in place that can eventually fill out the tree’s appearance.
7. Is the tree in a bad location? If the tree is near a power line or, as a result of the storm damage the tree is now very one-sided are heavy toward a building or structure, this may help with the decision. It may be best to remove such trees that are now a much greater threat for property damage.
Big Trees Are Tough!
A mature shade tree can usually survive the loss of one or two major limbs. The broken branch should be pruned back to the branch collar (Fig. 1). If the limb broke into the trunk, so that a clean branch collar prune is not possible, some bark removal may be needed to smooth the edge of the wound. When pruning large limbs, remember to use the 3-step pruning method.
Little Trees Are Tough!
Young trees can sustain quite a bit of damage and still recover quickly. If the central leader is intact, and the tree still has a manageable structure, remove the broken branches and let the tree recover.
Wait and See!
If a valuable tree is a borderline case and isn’t an immediate threat to cause damage, don’t make a hasty decision. It may be best to wait and see how the tree responds. Prune broken branches, give the tree a little time to recover, and then a final decision can be made.
Don’t Overdo It!
Don’t worry if the tree’s appearance isn’t perfect. With branches gone, the tree may look unbalanced or naked. You’ll be surprised how fast they will heal and grow new foliage. There is a tendency to overprune trees to balance the crown. Be conservative on the pruning…you can always remove more limbs later, but you can’t put them back!!
Don’t Add to the Shock!
Think about a dormant tree as a person under an anesthetic going into surgery to have his or her appendix removed. During the growing season, the tree is more like a person going into surgery without the anesthetic. A storm-damaged tree will be in a state of stress or shock. Make sure your tree first-aid is helping the tree and not creating more stress. After trees go dormant in the fall, they can tolerate much more physical activity with less stressful impact. Other than removing broken branches, try to wait until the trees in your area have shed their leaves to do any additional pruning for tree balance, etc. If you have a small tree that is partially uprooted, you may want to leave it in place if its roots still have soil around them. If it needs to be “replanted,” you may, again, be better off to wait till dormancy. The stress of the root damage from the move may be too much if done while the tree is actively growing.