Beech Leaf Disease Threatens Local Forests; Topic At Natural History Conference Saturday

BREWSTER – Cape Cod is known for its beaches, but it also boasts notable beeches.

Think of the Beech Forest in the Provincelands, the giant weeping beech at the Yarmouth botanical trail or the beech grove that caps the Lee Baldwin Trail at the Cape Cod Museum of Natural History in Brewster.

Unfortunately, Cape Cods beech trees are under assault from a devastating new disease; beech leaf disease. The disease first turned up in trees in Ohio in 2012 and just a few years after it was first spotted on Cape Cod in 2020 it’s been found from Falmouth to Provincetown.

Chris Brothers, the science department head at Falmouth High School and administrator of the Oyster Pond Environmental Trust, will be speaking on beech leaf disease at the Cape Cod Natural History Conference at Cape Cod Community College this Saturday.

The disease manifests itself in alternating dark and light stripes on beech leaves after they emerge from the buds in the spring. The leaves turn leathery and can die and drop off, denuding the trees.

“It’s not because I wanted to,” Brothers said of her interest in the disease. “Our [trust] property in Falmouth has a fair number of beech trees on it. I first learned about the disease in the Falmouth Enterprise. We did an informal survey (last June) and saw symptoms of beech leaf disease on virtually every tree. From that I did a fair amount of research on the disease.”

The trust considered treating the trees for the disease but there were too many, and they were reluctant to apply pesticide to a nature reserve.

“We decided to monitor the situation and see how it plays out,” Brothers said.

Will the trees survive or recover?

“It hasn’t been on the Cape long enough to know that,” Brothers said. “This is the first year we noticed it. A tree can be infected for several years before they show the banding in leaves. It is estimated trees can survive six to 10 years. It depends on how healthy the tree is in the beginning and how much rainfall they get, because then they can releaf in the summer.”

The speed the disease has spread is surprising.

“The Cape Cod National Seashore saw it in their park in 2021 in the beech forest. They are very concerned about that,” Brothers said.

Beech trees (Fagus grandifolia) are species of the climax forest in much of New England. Because they cast dense shade and can spread by root sprouts, they often form dense groves with nothing but beech, such as in Provincetown’s forest. However, last spring that forest was missing much of its leaf cover as the trees either failed to leaf out or saw their leaves drop.

Since 2012 the disease has spread to 12 eastern states. It has been linked to a non-native nematode Litylenchus crenatae meccannii, a roundworm that inhabits the leaf bud. It isn’t known if the nematode causes the disease or if it is a vector carrying a fungus or bacteria. If the leaves are undamaged when they emerge they will remain healthy, so the damage happens at the bud stage.

“The nematodes can be spread by wind, rainfall and birds,” Brothers said. “Right now we have questions, not answers. Also a similar disease to beech leaf disease has shown up in Japan.”

Brothers said OPET will continue to monitor their trees on 30 acres.

“It’s too large to treat,” she said of the Preserve. “It’s also a natural forest and disease is part of the ecosystem, but this disease is not native.”

She hopes to alert other biologists and conservationists on the Cape about the disease with her talk Saturday.

“We called other land trusts last year and their response was ‘what’s beech leaf disease?’” she said. “We’re at the beginning stages of awareness. We’ve seen plenty of other insect pests come and go. Trees can withstand these kinds of infestations. We can only go on what other places to the west of us have seen. They have eight to 10 more years of experience.”

The Natural History Conference opens at 8:30 a.m. Saturday, March 9, with registration. Presentations begin at 9 a.m. and continue throughout the day. Other topics include freshwater ponds, shorebird migration, the fish and shellfish population of Nauset Harbor, green turtles around the Cape and restoring cranberry bogs, grasslands and salt marshes.

This is the 27th annual conference presented by Mass Audubon at the college’s auditorium. The cost is $25, $15 for students, and it runs until 3:30 p.m.

“There is a lot of research happening on Cape,” noted conference coordinator Dave Shapiro. “The conference has been happening for 27 years now. It’s a nice way to get the public involved with science on the Cape and to introduce scientific concepts in a pretty indepth way. People are able to go up to a scientist and have conversations.”

He said 200 people usually attend from nature organizations, local towns, teachers and the general public.

“It’s a nice diverse audience and it’s great to see so many people,” he concluded.