When Will That Tree Fall on My House?

• Position: HOMEOWNERS

Have you ever wondered if the large trees by your house would fall on it during some wind or storm event? Actually, most trees in residential settings are sound and have many years of healthy life before becoming a hazard to your home. However, if your tree is unsafe, it could be a threat to lives and property.

"Many shade and ornamental trees are damaged throughout the year by windstorms, lightning, or ice and snow accumulations," notes Tchukki Andersen, staff arborist with the Tree Care Industry Association, Londonderry, N.H. "Damage usually consists of a few broken branches. However, more severe damage--such as splitting or pulling apart of branch unions, removal of large areas of bark, twisting and splitting of the trunk, or even uprooting--pose possible dangers."

A handful of species--including Chinese elm, silver maple, boxelder, and various poplars--have brittle wood that is broken easily. These rapidly growing trees cause a considerable amount of damage to homes, cars, buildings, and utility lines each year.

Homeowners should be aware of these characteristics and avoid planting them close to potential targets. If such trees already are growing in these locations, preventive pruning, bracing, or cabling may help reduce storm damage. This is particularly true as the tree grows in size and the weight and surface of the leaf and branch area increases.

Over the years, growing trees will add more leaves, become heavier, and "catch" more wind, so they are prone to increased mechanical stresses, thus increasing the chances of failure. Larger trees also will affect an...