Beech Leaf Disease and Hillside's Beech Trees
By Róisín O'Flaherty
2020 has been a difficult, disease-filled year, and it turns out humans aren’t the only ones who feel that way. Our local beech trees in Hillside Woods have been infected with beech leaf disease. This disease will kill a mature beech tree in about 6-10 years, and a younger one even more quickly. First discovered in Ohio (you don’t hear that often), the disease is believed to be associated with the presence of nematodes, a kind of worm. It’s unclear whether the disease is caused by the worms themselves or by pathogens carried by the worms. Beech leaf disease is especially concerning because beech trees constitute a large part of our local tree population: about 11% of Hillside Woods is American beech, and they are the fifth most common species of trees in all of NYS. Beeches are a valued nesting site for birds and provide food for a variety of wildlife, including squirrels, birds and deer. Losing our beech trees will be devastating.
You can recognize beeches by their smooth, grey bark, which often make them a target of graffiti. In fact, the word “beech” is thought to have contributed to the origin of the word “book,” as people used to carve runes into beech bark. Beech trees have dark green, oval leaves that have a pointed tip. Additionally, the side-veins coming off the mid-rib (the line down the middle of the leaf) are slanted and parallel to one another.
To determine whether a beech has been infected, you can look for striping - or banding - and shriveled-up curling of beech leaves. Beech leaf disease also manifests itself in decreased leaf and bud production, and a tree can have both infected and uninfected branches. Eventually, the leaves affected by disease will wither, yellow and die. Beech leaf disease can be confused for other things, including mildew, erineum patches, and anthracnose. To avoid confusion, looking for distinct banding, which is pretty much unique to beech leaf disease. You can also test for the nematode. Leaves from Hillside Woods beech trees have been analyzed by a DEC lab and tested positive.
If you notice beech leaf disease on your property, avoid moving fire wood or other lumber from that area, so that other beeches aren’t infected. If you see a beech tree that you believe has been infected, you can assist the DEC (Department of Environmental Conservation) in stopping the spread by photographing and emailing photos and location info to foresthealth@dec.ny.gov.
For more information, visit the DEC beech leaf disease info page or this article from the American Association for the Advancement of Science.