Nor’easters and Tree Growth


I am sure given the current condition of the roads and the power lines we are all aware of how the recent Nor’easter affected our personal lives. I want to tell you all about how storms like the one last week can impact our forests. A little bit of background: both hurricanes and nor’easters are large storms that form over the Atlantic Ocean. Where a nor’easter thrives on cold air in the atmosphere, a hurricane needs warm air, which is why we see them in the summertime. This is also why we rarely see nor’easters outside of the Northern Atlantic region.

As we saw, these high wind storms can topple trees and do serious damage to our infrastructure. A combination of heavy rain and fast winds can uproot even the oldest and seemingly sturdiest oaks in the forest. On the surface it would seem like the landscape naturally recovers. After all, if we weren’t around to clear out all the debris wouldn’t it eventually decay? Correct! The fallen branches and downed trees would rot over time but there is far more happening than our eyes can see.

It would appear that when a large storm comes around there is a major difference in the way forests react in the following year.  A study from 2018 found that in years with multiple major storms, tree ring growth was impacted for up to four years. If you took a tree cookie (which is just a slice out of a tree) you would be able to see the impact of the 2017 hurricane/nor’easter season on its growth. This study even found a statistically significant correlation between the magnitude of growth decline and the storm characteristics (I.e., wind speed and storm surge height). Tree rings/tree cookies can tell us a lot about the history of a place not just how old a particular grove of pines or oaks is. They can show regional climate and temperature trends, seasonal changes, and even past water conditions for a given year. Now scientists are using them as a predictor of vegetative responses to severe weather events. As these storms become more frequent it will be even more important to know how our ecosystems respond to them.