Fewer Acorns, More Lyme Disease

I think acorn production was lower in the Madison area this fall, at least on the oak trees I have watched over the years.

Last year there were plently of acorns for the little guys around our home.

“I remember going into areas and you’d get the crunch of acorns under your feet,” said Neil Calvanese, vice president for operations at the Central Park Conservancy. “And this year, you kind of have to search around for them.”

It is a phenomenon happening not only in New York but also throughout the Northeast. While last fall set a recorded high for acorn production, at roughly 250 pounds per tree, this year is seeing a recorded low, with a typical tree shedding less than half a pound of its seeds, said Mark Ashton, a forest ecologist at Yale University. On average, oaks produce about 25 to 30 pounds of acorns a year.

Coming on the heels of an acorn glut, the dearth this year will probably have a cascade of effects on the forest ecosystem, culling the populations of squirrels, field mice and ground-nesting birds. And because the now-overgrown field mouse population will crash, legions of ticks — some infected with Lyme disease — will be aggressively pursuing new hosts, like humans.

“We expect 2012 to be the worst year for Lyme disease risk ever,” said Richard S. Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies in Millbrook, N.Y. “We are already planning educational materials.”