We planted two maple trees near our home 15 years ago that have grown to over 50 feet tall. We are worried that they might break and damage our house in a storm. A friend with a chain saw says he can reduce their size by about a third. Is that a good idea?
Arbitrarily shortening all branches on a mature tree is referred to as “topping.” Topping is never a good idea. Simply reducing the height of a large tree does not make it safer. In fact, improper pruning can make a large tree even more dangerous. The trees will respond by quickly growing back to their normal mature size within a year or two. But there will be an explosion of five to 10 times as many thin, weaker branches which will be poorly attached and much more easily broken in a storm. It will require much less wind to bring them down.
The wounds created by stubbing large branches are more subject to insect and disease infection. Some of them will die back, creating an even larger target for infection. The multitude of small branches growing like a witch’s broom on the end of bare larger branches destroys the natural shape and beauty of the tree.
If you are concerned about wind damage to trees, the best way to prune them is to open them up by removing some of the inner branches so that wind can blow through the trees more readily. This practice is often called “wind sailing” because it allows the wind to sail through with less resistance. Branches growing inward or upward are removed, leaving branches growing outward.
