Falling trees have become a major topic in the wake of this summer’s torrential storms (not to mention the record snows of last winter). We have all been frustrated by power outages. Some neighbors also suffered serious damage to their homes or cars (see photos in this issue).
Pepco continues to blame trees and squirrels for its unreliable service, rather than facing up to its maintenance backlog and inefficient management. With all of this, it’s not surprising that some residents, feeling “powerless” (in both senses of the word), have suggested removing or radically pruning large trees.
Before getting out the chainsaw, however, it makes sense to take a closer look at the risks (and benefits) of trees. It’s natural to worry most about risks that we cannot control, such as the weather or shark attacks. This leads us to overestimate the magnitude of the risk involved.
So how do we objectively understand the risk posed by large trees? Here are some numbers:
Still, many people think having fewer trees lessens the risk. In reality, the isolated tree is more likely to fall, while a heavily wooded area remains unscathed. After all, that’s why people used to plant windbreaks.
To actually gauge the risk posed by a specific tree, an arborist will conduct a hazard assessment. This takes into account the health and structural integrity of the tree, its species, soil conditions, and the distance to a “target.”
In other words, an unstable tree in the middle of a forest would be a low hazard, because there’s no target nearby. If the same tree was right next to a house or a playground, it would pose a greater hazard.
If you have concerns about a particular tree, it’s best to get a professional assessment. You may be surprised at the result. A leaning tree, for example, is not necessarily unsafe.
In our next issue, we’ll examine tree trimming. Correctly done, tree trimming keeps power lines clear and helps trees withstand wind and ice. Improper pruning, however, has the opposite effect. We will also look at what makes a good street tree, and the many benefits they provide. ■
*“Deaths from Wind-Related Tree Failures,” by Thomas W. Schmidlin, Ph.D.Part 2: How Trees Enhance Our Lives Part 3: Stumped About Stumps?
© 2010 NFCCA [Source: https://nfcca.org/news/nn201010d.html]