Questions & Answers

Q. There is a stand of apparently dead trees (~ 200 feet long) along the eastern side of northbound William Floyd Parkway, north of the BNL entrance. Do you know what caused this condition?

A. What people are seeing is the result of Brood XVI of 17-year periodical cicadas (Magicicada septemdecim). The emergence of the cicadas was widely reported in Newsday, but the effects of the cicadas was not as widely reported. I did a piece on News 12 a couple weeks ago, and we've done several notifications to our employees. When the cicadas emerge they spend 2-3 weeks mating with the females laying their eggs at the tips of trees (mostly
oaks and other hardwoods). The process involves the females cutting numerous slits in the bark to lay their eggs. The tips (18 -24") are heavily damaged by the process and eventually die. The eggs hatch and the larvae drop to the ground to feed on roots for another 17 years. The end result is a lot of minor damage to the tips of the branches only. The trees will look bad, and may continue to worsen through the summer, but they are not dying and will recover next spring. The area along William Floyd and elsewhere on BNL and in Ridge was hit particularly hard because the emergence of cicadas was large. This area is mostly wild and no pesticides are used. Therefore, the cicadas have a much higher likelihood of surviving. The same phenomenon is occurring elsewhere on Long Island, in neighborhoods, but is not as prominent since many home owners utilize various methods of ridding lawns for grubs and other insects, including cicadas. And development has removed a lot of the trees and roots that the cicadas need for survival.

So, I view the heavy damage near BNL as a good thing because this area will be the site of future emergences.

Dr. Timothy Green
Cultural and Natural Resources Manager