There is a new threat to Connecticut forests as beech leaf disease spreads rapidly and Great Mountain Forest is playing a role in fighting it.
Plant pathologist Robert Marra, lead investigator with the Connecticut Agricultural Experiment Station in New Haven, is using a plot in GMF as one of 11 stations in Connecticut to monitor the progression of the newly diagnosed disease, which was first identified in Ohio in 2012.
The Great Mountain Forest plot is one of two in Litchfield County. Trees there are measured annually to see how they have changed and what can be determined about regeneration.
Dr. Marra appeared at the Norfolk Library last Sunday in a program sponsored by the Norfolk Conservation Commission. “By 2022, we realized we had big, big problem,” he said. “We were seeing a beech leaf disease Hell-scape and knew we are dealing with a disease that is not going away soon.”
Beech leaf disease causes mortality in saplings as well as mature beech trees, which Marra described as a foundational species in some forests.
It has now been determined that an invasive nematode (a microscopic round worm) is responsible for the disease, which is spread when the nematode population burgeons in late summer and fall. The leaves fall into puddles and the nematodes exit through the leave’s stomata into the water, where they can be carried to other trees by insects, birds or mammals.
Finding a cure is a long way off, but trees can be treated with phosphite products. Researchers have had encouraging results by drenching the soil around beech saplings with the products twice a year. Phosphites are inexpensive, do not need a certified applicator and do not harm other creatures.
Marra said phosphites reduce tree mortality, sustaining a large enough population for genetic diversity once a cure is found.