Coping with Forest Threats
Apart from the elimination of trees that comes from development, acid rain, and global warming, the greatest immediate threats to the forest products industry (fuel, lumbering, and maple sugar production, etc.) come from invasive insects: specifically the Emerald Ash Borer, Asian Longhorn Beetle, and the Wooly Adelgid. The adelgid is already in Vermont. The Asian Longhorn Beetle is 50 miles away in Worcester, MA, where it devastated 65 square miles, and the Emerald Ash Borer is 30 miles away from the Vermont border in Quebec, Canada. All are on the move, and global warming is diminishing the cold’s lethal effect on them. Therefore residents and visitors are urged NOT to transport any diseased wood and NOT to move any firewood more than 50 miles. Instead, buy local firewood. These insects could have a devastating effect on Vermont and other New England forests.
The target of the Emerald Ash Borer is obvious, and combined ash species make ash the tenth most common tree in Vermont. This powerful, tiny insect killed more than 40 million trees in Michigan because it heads straight to the cambium layer of the trees…the business layer. You can see its serpentine munching meanderings, which quickly girdle the tree, under the bark. Not so obvious to the eye as the much larger Asian Longhorn Beetle, the borer has a distinctive dark green color. Also distinctive are its exit holes, which look like a capital D, about 1/8” wide, lying on its back. The Asian Longhorn Beetle, on the other hand, prefers maples, although it will attack birches, elms, horsechestnuts, willows and, occasionally, ashes, Euro-pean mountain ash, London plane tree, mimosa, and poplars. The only good points about this enemy are that it is big and distinctive, and it works more slowly than the Ash Borer because it burrows into the heartwood of the trees and not the more important cambium layer. The larva is huge. The shiny beetle’s exterior looks like black patent leather with clear white spots even on its antennae. Its larval exit holes are round and about _ inch in diameter. When found, the adult beetle should be put in a jar and frozen. Then call toll free 866-702-9938. The infested trees will need to be removed, chipped, and burned swiftly.
The Wooly Adelgid was noticed in Vermont in 2007. It infects hemlocks, which are Vermont’s seventh most common tree. Hemlocks help with deer cover in winter, provide bank stabilization and prevent sedimentation of waterways, aid water quality by filtering pollutants and nutrients, and help fish populations by shading and cooling streams. Emissible oil spray in the early spring helps smother the insects and doesn’t hurt the plants. Serious cases of infestation might require insecticides, but whole forests are impossible to control, so early detection is essential. Some scientists believe the insect is spread by birds, as well as by wind and transportation of infected wood items, and are suggesting that any birdfeeders or birdhouses be positioned at least 100’ away from any hemlock trees, especially those that are already infected.
Citizen scientists and interested individuals are being trained and urged to be on the lookout for these insects. Report sightings to the Vermont Forest Biology Laboratory at 802-241-3609. For more information visit www.emeraldashborer.info, www.aphis.usda.gov, www.saveourhemlocks.org, www.anr.state.vt.us.
To see a series of humorous videos about a most serious pest, visit www.dontmovefirewood.org and especially “The Emerson Family Goes Camping.” You also can pick up ID cards and free informative fliers on these dangerous insects at the Museum.
