Filed under: Noticing Nature.
While turning off Saranac onto Sugarshack trail recently, I had to duck under this mature Beech tree whose trunk had broken about 7-9 feet above the ground.
This phenomenon is called Beech snap and it can be caused by wind or by Beech Bark disease, a fungal disease. Beech is one of our hardwood species that is most susceptible to wind damage and there had been a very windy front come through with a recent snowstorm. Evidence of Beech Bark disease includes ugly, black-rimmed wounds in the normally smooth gray bark. These wounds, called cankers, are usually several inches long. There is another sign of infection that will precede the cankers but requires a close look at the bark. Tiny white tufts growing out of cracks in the bark indicate the presence of the scale insect that makes the entry point for the fungus that causes Beech Bark disease. These tufts were easy to see on the bark of the fallen tree so it could have been wind or disease that caused this Beech to snap.
Scale insects are tiny insects that are related to aphids and similarly have a straw-like mouth used to feed on plant sap. The scale insects use their mouthparts like a miniature tap to access the sap in the inner bark. They feed and reproduce on the bark and their offspring move to nearby trees. The disease fungus spores, carried by the wind, land on the bark and grow through the holes left by the insect mouthparts. Once under the bark, the disease fungus slowly kills the tissues that transport water and nutrients. The good news is, some trees seem to be resistant to this disease and there have been cases in which beech saplings have sprouted from the roots of trees that were killed by the disease. The scale insect that paves the way for Beech Bark disease was introduced into Nova Scotia in the late 1800’s and has been slowly expanding its range southward since. Areas without the scale insect do not have problems with this disease.