The Conway Scenic Railroad crosses a trestle as it takes passengers on a fall foliage excursion through Crawford Notch, N.H., Sunday, Oct. 1, 2017. Credit: Robert F. Bukaty / AP

NORTH CONWAY, N.H. — Surveyors with the New Hampshire Division of Forests and Lands have found widespread defoliation attributed to a population boom of moth caterpillars.

Kyle Lombard, the coordinator of the division’s forest health program, said that the department has surveyed 20 percent of the state and found 30,000 acres of defoliation.

The affected trees are primarily clumps of red and black oaks, WCVB-TV reported.

The last time the state experienced more than 10,000 to 15,000 acres of defoliation was in 1992, according to the department.

Lombard said that areas with a lot of oaks will look weird; however, the defoliation should not affect the foliage season. The trees that largely produce the bright oranges, reds and yellows are primarily maples, aspens and ash, which are not affected by the moth larvae.

Lombard said that the real concern is that if the moth population continues to explode it will increase the amount of dry brush across a larger area.

“If this thing spreads with another 60,000 acres and jumps all the way through the Lakes Region and across into Grafton County, then you’re talking about fire risks in some of those ventral and northern Belknap areas,” he said.