Beloved Beech Trees Wracked By Fatal Disease: See Its Impact In NJ

NEW JERSEY— Millions of beech trees provide shade to New Jersey streets, cover forested areas, and provide food sources for local wildlife. But an emerging threat that could be even more damaging to the ecosystem than the spotted lanternfly is killing these trees, experts say.

The lethal Beech Leaf Disease (BLD) affects both young and mature American beech trees, and can kill a mature tree in six to 10 years. Younger trees may die quicker than that.

The disease may be caused or carried by a type of nematode (worm) that eats buds and leaves off of the trees. This makes some leaves emerge with leathery, dark green parts that may turn yellow or brown as the season continues, according to Science.org. The damaged leaves fall off and cause the tree to use extra energy growing new ones.

Where has beech leaf disease been detected in New Jersey?

BLD was first detected in New Jersey in 2020, in both Essex and Bergen Counties according to Department of Environmental Protection spokesperson Larry Hajna. The disease has been found in 12 of New Jersey’s 22 counties as of mid-May, Hajna added: Bergen, Essex, Sussex, Passaic, Warren, Morris, Somerset, Union, Hunterdon, Mercer, Monmouth, and Burlington.

It affects American, European and Oriental beech trees, according to the DEP.

“The New Jersey Forest Service has established long term monitoring plots to study progression and proliferation of beech leaf disease across the state,” Hajna said. “These plots are surveyed annually and data obtained from the plots is used in a multi-state initiative to further map the presence of the disease throughout the United States.”

American beech trees are common in eastern U.S. forests, and beech leaf disease has been found in 10 states as well as Ontario. The disease was first detected in northeast Ohio in 2012 and now affects trees from Michigan to Maine. The U.S. Forest Service has been studying the extent of Beech Leaf Disease, and how severe it may be.

BLD is different from the previously-known beech bark disease, which can affect beech trees concurrently with the leaf disease.

How many beech trees are in New Jersey?

There could be upwards of 12 million beech trees in New Jersey, taking into account saplings and young trees. There are more than 2.8 million beech trees in New Jersey that have grown to a diameter of five inches at breast height (where the tree is measured), according to U.S. Forest Service data.

What does beech leaf disease look like?

Primary symptoms of infected trees are dark bands between leaf veins, according to the state Department of Environmental Protection and Rutgers University. These can be seen when holding a leaf up to a light source, or looking up through a canopy.

"As the disease progresses, more leaves become affected and additional symptoms, including browning leaf edges that begin to curl, leathery leaf texture and early defoliation, may become apparent," said DEP officials. "Eventually, tree mortality will occur."

And, late spring is a good time to identify trees that may be infected, since their leaves are full and may show signs of disease.

What can people do about beech leaf disease?

Experts are still figuring out how to best manage beech leaf disease. Researchers have “encouraging results” with treating beech saplings with a phosphite product twice a year, according to a study from the University of Rhode Island.

Hajna said that while there is currently no best way to treat or prevent beech leaf disease, forestry experts must monitor it and share information with the public on how to spot it.

“As beech leaf disease is an emerging pest in many states, there is not a complete understanding of best management practices for controlling the disease,” he said.

Property owners who spot a beech tree that may have BLD can report it to the NJ Forest Service’s Forest Health program at foresthealth@dep.nj.gov, or call 609-292-2532.

Rutgers’ plant diagnostic lab is “also a very good and helpful resource,” Hajna added.

“Landowners can submit plant samples to the lab to determine if their tree is infested with beech leaf disease or to detect pests that impact other species of plants,” he said.

Scientists at Rutgers add it is important to monitor trees closely, and restrict moving plant materials from place to place.

"BLD has spread very quickly eastward in the United States and is concerning to all of us," said the Plant Diagnostic Laboratory in a December 2021 article.