Cold weather may help the hemlocks
I have a special fondness for hemlock trees because to me they symbolize the very essence of the north woods. Between New York and Pennsylvania, I bow hunt from at last six different treestands and they are all hung in hemlock trees. The thick branches of a hemlock give me plenty of cover and even offer some protection from a light rain. I can’t imagine hunting from any other tree unless it’s a white pine.
The Eastern hemlock is extremely important to forest ecology because various species of birds depend on it for shelter, food, or as a nesting site. For deer, stands of hemlock often spell the difference between living and dying during periods of harsh winter weather. As important as hemlocks are to forest ecology, they are under attack.
According to information provided by the Pennsylvania Department of Conservation and Natural Resources, the Hemlock Woolly adelgid (HWA) is an aphid-like bug native to Japan and possibly China and was introduced from Asia into the Pacific Northwest in 1924. It was probably introduced into the northeastern United States in the 1950s, and was first discovered in Pennsylvania in 1967. To date, 49 of Pennsylvania’s 67 counties in the eastern two-thirds of the state have been infested by this insect and I was more than a bit concerned when I recently heard the wooly adelgid was discovered knocking on New York’s border.
The wooly adelgid is attacking and ultimately killing hemlock trees by laying its eggs on the underside of hemlock branches. When the insects hatch, they begin sucking the sap from the needles, causing them to fall. In a few years, the tree dies. As incomprehensible as it sounds, there is a very real possibility this insect could eradicate the hemlock from its present range.
Some foresters feel the woolly adelgid is greater threat to our forests than is the emerald ash borer. Currently, forest scientists are looking at ways to control this insect, and the biggest hope seems to lay in a biological control. There are native species of insects that prey on the woolly adelgid, but none has had a significant impact on adelgid numbers.
I’ve heard a number of people complain about this year’s winter weather, and for good reason. So far this year we’ve had more than 10 days of sub-zero weather, but that isn’t all bad. It seems the one thing the wooly adelgid can’t survive is bitter cold weather, so these past few weeks may be a left-handed blessing.
Scientists are currently working to find a biological control, but until that happens I look at bitter cold weather as a friend to the hemlocks. If hemlock trees die off in great numbers it could change the forest ecosystem. Let’s hope this doesn’t happen.