Glenn's Sheds

Glenn's Sheds

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Oak Trees in New York State Are Dying

Oak trees with and without Oak Wilt

Oak wilt is a disease that affects oak trees. It is caused by Ceratocystis fagacearum, a fungus that develops in the xylem, the water carrying cells of trees.

All oaks are susceptible to the fungus, but the red oak group (with pointed leaf tips) often die much faster than white oaks (rounded leaf tips). Red oaks can take from a few weeks to six months to die and they spread the disease quickly. White oaks can take years to die and have a lower risk of spreading the disease.

Why is oak wilt a problem?

The oak wilt fungus blocks the flow of water and nutrients from the roots to the crown, causing the leaves to wilt and fall off, usually killing the tree. Red oaks (scarlet oak, pin oak, black oak, etc.) can die within a few weeks to six months, and the disease spreads quickly from tree to tree. White oaks (bur oak, scrub oak, etc.), however, often take years to die and the disease usually cannot spread to additional trees.

Where does it come from?

Oak wilt was first discovered in Wisconsin in 1944, but where it originated is still unknown. It has spread throughout the Midwest and Texas, killing tens of thousands of trees.

Where is it found in New York State?

In 2008, a small infection was discovered in Glenville, NY. It was quickly dealt with to prevent further spread. The disease resurfaced in the same location in 2013, and additional steps were taken to eradicate the infection. In 2016, oak wilt was discovered in Islip, Riverhead, and Southold in Suffolk County; Brooklyn in Kings County; and Canandaigua in Ontario County. View maps showing current infection locations. (PDF, 880 KB) View the emergency orders that establish Protective Zones around the infections and prohibit the movement of oak and firewood out of the infected areas:

How does it spread?

There are two main ways oak wilt is spread: 1) above ground by beetles, and 2) below ground through tree roots.

Fungal spore mats form just under the bark of infected red oaks after they have died from the disease. During the warmer months, these spore mats emit a sweet odor that attracts sap-feeding beetles and bark beetles, which can pick up fungal spores as they crawl around. The beetles are also highly attracted to fresh wounds in other trees-often caused by pruning. In this way, they spread the fungus from infected trees to healthy trees sometimes miles away. Infected firewood and other wood materials also pose a threat because they can harbor the fungus and/or beetles that can spread the disease.

Spread underground occurs when roots of nearby red oaks graft to each other (fuse together), creating a connection through which nutrients and the disease can move. In the Midwest, large blocks of red oak forests have died from the disease in a single season due to their vast network of interconnected roots. In contrast, white oaks are much less likely to create root grafts, and spore mats rarely form under their bark, significantly reducing the chance of spread from these trees.


Symptoms of oak wilt infection are often very noticeable in red oak species, but aren’t easily seen in white oaks.


What is being done?

What can I do?

And this …

New York battles continuing spread of deadly oak wilt

The Cornell Plant Disease Diagnostic Clinic in Ithaca, New York, has identified the presence of oak wilt in the borough of Brooklyn in Kings County and in the towns of Babylon, Islip, Riverhead and Southold in Suffolk County.

This is the fourth county where oak wilt has been confirmed in New York. It was found in Long Island in August 2016. Reports of symptomatic oak trees from both tree-care professionals and the public has led to the additional detections.

The New York State Department of Environmental Conservation (DEC) will remove and destroy all the oaks that have tested positive for the fungus. It has issued emergency orders to establish protective zones encompassing all of Suffolk County and the borough of Brooklyn.

The orders forbid the removal of any living, dead, standing, cut or fallen oak trees or any portions thereof, including branches, logs, stumps or roots and green oak lumber and firewood, out of the zone unless it has been chipped to less than 1 inch in two dimensions.

“It is important that these emergency orders are taken seriously,” said DEC Commissioner Basil Seggos. “Moving contaminated wood without taking precautions will spread this serious tree-killing disease to additional areas.”


About Glenn: Glenn of Glenn’s Sheds is the mastermind behind their line of durable, breathable, and beautiful firewood sheds. A lifelong woodsman Glenn has heated his home with firewood all his life. He’s an expert on trees, firewood, burning, techniques, woodstove-care, and, of course, firewood shed building and installation.