Tree Damage
FROM THE DESK OF - Martha Maletta, Horticultural Consultant
DATED - February 9, 2004

It doesn’t necessarily take a storm – wind, snow, ice – for tree damage to happen. It was a still August evening when a significant section of the old sugar maple in my back yard crashed to the ground taking a small portion of the back porch with it. The cause: a hidden structural defect and decay like we’ve had recently can and do cause tree damage, even to healthy trees. Deciding how to deal with storm-damaged trees depends on case-by-case evaluation. Information from the USDA Forest Service and the International Society of Arboriculture provided through The National Arbor Day Foundation provides some general guidance.

The damage needs to be assessed, of course, before deciding what to do. A tree that was vigorous and healthy before the storm will have the best chance of recovering, depending on the extent of the damage. If major limbs have broken, especially a large number of them, recovery will be more difficult. If a significant portion of the top of a central leader tree has been lost, the tree may be permanently disfigured.

A rule of thumb for likely survivability: at least 50 percent of the tree’s branches are intact. However, the larger the wounds are in relation to the size of the intact branch or trunk, the longer they will take to callous over, leaving the site vulnerable to decay or insect invasion. A judgment also needs to be made as to whether the remains of the tree may be able to form new branches that will result in a structurally sound tree with reasonable appearance. The species, location and value of the tree - aesthetic or sentimental – should also be factored into the decision about what to do.

Trees that are the best candidate’s for repair are: mature, healthy trees that have lost one major branch; trees with minor damage – some broken limbs, but major limbs intact; young trees, even with significant damage, as long as the leader (or a strong lateral near the top) remains. Some cases warrant a “wait and see” approach. Healthy mature trees with several major branches damaged may recover given time. Broken portions must be removed, but hold off on additional pruning until the prognosis is clearer. There are other cases when removal is generally the right solution: most of the crown (branches) of the tree, even a healthy or young one, are gone; split trunk; breakage that reveals decay.

Tree work, especially on mature trees, requires a professional arborist. Evaluation of structural soundness as well as assessment of repairs can only be done on-site and on a case-by-case basis. For guidance hiring an arborist and a list of New Jersey Certified Tree Experts serving Hunterdon County, contact Cooperative Extension at 980-788-1339, or stop by the Extension Center on Rt. 31, M-F, 8:30 to 4:30.

Wind can damage trees, but trees can provide protection from wind. A properly sited planting of carefully chosen trees can modify the impact of wind on a home and property and even reduce heating costs. It is obvious that, to break the wind, the planting must be upwind from the home, and perpendicular to the direction of the prevailing winter winds, generally the northwest in New Jersey. Local conditions can shift winds and that must be taken into account.

The most effective distance for a windbreak planting depends on tree height. Maximum wind velocity reduction occurs at a distance from the trees equal to 1 to 3 times the height of the trees, though some benefit extends well beyond that distance. Height of the area in which wind is reduced is about the height of the trees. As the trees grow, the area of maximum velocity reduction will extend further from the tree and the height of effective reduction will increase. A rule of thumb for a single story home is to plant the windbreak 40 to 50 ft away, 15 ft being considered the minimum effective tree height for that house. Clearly, a taller home would require taller screening.

Maximum wind breaking is achieved with several stagger rows of evergreen trees with trees in at least the outer and inner rows having branches to near the ground. If possible, the rows should extend 50 ft beyond the side of the area being protected. Since snow will drift in the area just down wind from the trees, the break should be located to take this into consideration. Evergreens suitable for wind breaks in New Jersey include: white pine; Japanese black pine; Scotch pine; Norway and blue spruce; white fir; American holly; arborvitae (watch out for deer!). A mixed planting is usually more desirable than a planting of only one species.