Why Do Some Trees Fall in a Storm While Others Stay Standing?
Since Sandy, the Parks Department has recorded 8,577 street trees down, 3,365 fallen limbs and 1,297 hanging branches, reports the New York Times. The department received 20,044 tree-service requests, which resulted in more than 13,000 work orders.
In our neighborhood, dozens of enormous century-old trees fell, wreaking havoc throughout the area. After the chainsaws were unplugged, neighbors had questions.
“The trees in Ditmas Park seem much more susceptible to falling and breaking than in other BK neighborhoods,” wrote commenter Carmen Sognonvi. “Is there a reason for that?
A new article in the Scientific American asked three experts why some trees fall over in a storm while others stay standing. The answers are interesting, varied and uncertain. They reveal more complexity than simply old versus new — it’s both what’s on top and what’s below ground that counts.
A few reasons for falling beyond old age:
• Windthrow uproots taller trees. The tree trunk acts as a lever and the force applied to the roots and trunk increases with height. Large canopies can “act as sails” in high winds.
• Urban trees’ roots can be cut, crushed and torn. If roots don’t fully develop, there may be ensuing decay.
• It’s possible for young and old trees to topple even with little rain or wind if the root systems are decayed or shallow.
If you’re wondering about the trees near your home, tests such as the Resistograph Drill Test and Sonic Tomography are available. The experts even offer major signs to look for such as an increasing lean (bad), full foliage in growing season (good) or cracks between roots (bad). Helpfully, they also say that certain sorts of mushrooms may lead to wood decay while others do no harm. It’s easy to be scared of the unknown.
If you’re seriously concerned, the right move is to call the city at 311. You can also call specialists such as Savatree or Urban Arborist to help with your large neighbors. Yelp isn’t particularly helpful on the subject, so if you have any recommendations for tree services, let everyone know in the comments.