Some of the state's trees may be in danger of disease.

New Hampshire forestry officials are concerned about a new oak tree-killing disease that may be making its way to the Granite State and the public is being asked to watch for danger signs.

Oak Wilt disease has been in the Great Lakes region for decades but recent outbreaks in Albany and Long Island, New York have New Hampshire officials on alert.

Red oaks — which have pointy-tipped leaves — are most susceptible to the disease and can die within a few weeks to six months of being infected. White oaks — which can be identified by round-tipped leaves — are less vulnerable.

Oak Wilt is a fungus that affects the vascular system of most oak species, stopping the movement of fluids throughout the infected tree, which then quickly dies of dehydration.  The disease is spread over long distances through the transportation of infected logs and firewood. Over short distances, it is spread through root grafting as well as by beetles that ingest sap from infected trees and then travel to other trees.

Once an oak tree is infected with the disease, it cannot be saved. It is possible, however, to control and eradicate the disease’s spread to other trees, making it critical to find outbreaks early.

Trees with Oak Wilt disease are easily identified as they drop their leaves during the summer, starting at the top of the tree.

Anyone noticing an oak tree that shed its foliage in July or August is asked to contact the N.H. Division of Forests and Lands’ Forest Health Program at 603-464-3016 or to go to and submit a report that can also include a picture.

Part of the state Department of Natural and Cultural Resources, the Division of Forests and Lands protects and promotes the value provided by trees, forests and natural communities. For more information about the Division of Forests and Lands and the work of its Forest Health Program, visit or call 603-271-2214.

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