On Tree Health

Data collected by the New York Department of Environmental Conservation (DEC) states that about 76% of New York’s forests are privately owned. This is about 14.4 million acres total, owned by almost 700,000 different landowners in our state. When we think about managing invasive forest pests on a statewide scale, those landowners are an incredibly important part of conserving New York’s forests into the future.

When it comes to managing hemlock woolly adelgid (HWA) on private lands, landowners should be looking for presence or absence of HWA as well as the overall health of the hemlock trees on their properties. This time of year hemlock trees should be putting on new growth, which appears as bright, lime green buds all over the tree. If trees are not exhibiting ample new growth, it could be a sign that the tree has an HWA infestation and is in severe decline. In the photo at right, the hemlock with the silver fly biocontrol release bag is showing bright green tips on its twigs, giving us a sign that this hemlock, though infested, is relatively healthy and could provide a good release site for the next few seasons.

For landowners looking for an easy way to assess tree health, the presence or absence of new buds can be sign that your hemlocks are in trouble. By monitoring the growth of your hemlocks early in the summer, you can determine if any management steps need to be taken to prevent hemlock decline and death on your property. If you see a lack of bright green shoots on your hemlocks, surveying for HWA infestations is the next step. As always, don’t forget to report your findings if you see HWA in your area!

Landowners and citizen scientists who are interested in recording tree health on their property or in their area may use our Tree Health Assessment sheet and accompanying picture guide as a general outline for surveying for hemlock health. Those interested in surveying local tree health to help us find potential release sites for our biocontrol program may email nyshemlockinitiative@cornell.edu for more information. [Please note that we currently do not release on privately-owned land and that our biocontrol bugs are not currently available for commercial sale or use.]