Late-season frost affected NH oaks; rebound expected mid-summer

While spring leaf development of New Hampshire’s oak trees was severely affected by an unusually deep late-season frost on May 18, it is unlikely the trees sustained permanent damage, according to the N.H. Division of Forests and Lands.

“Oak is particularly sensitive to frost during the two-week window after the buds break and that's why it has adapted to ‘leafing out’ later than most trees in New Hampshire,” said Kyle Lombard, program director for the NHDFL’s Forest Health Program.

“The good news is that oak can lose these first leaves and put a second set out in the same year, so by July the oaks should look as they usually do.”

Oak leaf drop has been observed from Coös County all the way to Nashua. Current estimation is that more than 100,000 acres were affected by the cold snap.

NHDFL has tracked frost events for more than 100 years and effects of the recent frost are the worst on record.

The damage from the May frost should not be confused with oak wilt, a serious invasive pathogen that the NHDFL has been monitoring but that has not yet arrived in New Hampshire. Oak wilt is not active until mid-summer when mature oak leaves suddenly drop on a single tree.

New Hampshire's Division of Forests and Lands is part of the Department of Natural and Cultural Resources. NHDFL’s mission is to protect and promote the values provided by trees, forests and natural communities. This mission is accomplished through responsible management of the state’s forested resources; by providing forest resource information and education to the public; and through the protection of these resources for the continuing benefit of the state’s citizens, visitors, and forest industry. Learn more at nhdfl.dncr.nh.gov.

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