NEWBURYPORT — Do the trees know something we don't?

Oak trees across the country are reportedly producing a mysteriously low number of acorns this season, with only limited areas of Massachusetts and a handful of states reporting typical to banner years for the nuts, a significant food source for wild animals.

Though some reports find Greater Newburyport's crop more typical than other parts of the state, Department of Conservation and Recreation (DCR) Forest Health Supervisor George Hubley says northeast Massachusetts is seeing a dramatic drop in its acorn production this year, and he's not sure of the cause.

"I've seen a lot less acorns in most of the areas I've gone to this year," said Hubley, who's charged with monitoring the health of trees across a wide swath of the state that encompasses Newburyport, Amesbury, Salisbury and extends as far as Lowell, Lawrence and Methuen.

"I'm not sure of the exact cause, but I do know that with oak trees, if the tree is under some sort of stress from drought or insects, the tree will hold off on letting go of any acorns so it can keep its nutrients for the next growing season."

Many birds and mammals in the eastern forest depend on acorns as a staple in their diet. Black bear, white-tailed deer, white-footed deer mice, squirrels, turkeys and grouse are just a few whose populations could be challenged in the event of a vast acorn shortage.

While reports vary locally, according to some residents posting on Internet chat boards, in areas of Weymouth, Worcester, Lowell, Jamaica Plain, Acton and Boxford, acorns are severely diminished, and the native squirrels are getting restless.

Due to shortages in these areas and in areas west of Massachusetts, animals that normally feast on the nuts are instead feasting on neighborhood pumpkins, pear trees and Japanese maples, and becoming victims to cars as they cross the street into unfamiliar territory looking for food.

Some animal lovers in those areas have posted they're worried enough about the critters they've started providing for them by smearing barren trees with peanut butter and filling their bird feeders with nuts.

Reports of acorn shortages are coming in all the way from California to New York, Connecticut, New Jersey, Virginia and Maryland, which find not just a decrease in the number of acorns dropping, but in many cases "zero" acorns dropping from majestic oaks that have produced copious amount of acorns for the past 30 years.

"I have a friend from Indiana who called me last week and wanted to know why the trees weren't producing acorns this year," said Amesbury Tree Committee Member Richard Gale, who still maintains his landscape architect business in Indiana. "I told him I didn't know."

The majestic oaks of Arlington National Cemetery are reportedly without a crop this year. In Massachusetts, trees located near the Cape and Islands and in the southeast coastal regions of the state are reportedly raining acorns, in some cases reaching nuisance proportion as they're known to put small dents in people's cars and pelt unsuspecting passersby as they walk under them.

In the Boston area, acorn yield seems to be sporadic.

"It's not been a banner year here for acorns," says State Forester Harry Peneman, whose area of oversight extends from Essex and Middlesex County, all the way from Hopkinton to Salisbury.

"There are some acorns around," he added. "When there's a bumper crop, they get so thick on the ground that you can't walk. It's like walking on ball bearings. But I haven't had a bumper crop in a few years now. It's a cyclical thing."

The natural cycle of the oak, experts say, is designed to maximize its own chances at survival. While significant rainfall is known to help yield a good crop of acorns, and lack of rainfall inhibits that production, there are some unexplained aspects to barren years that scientists attribute to Mother Nature and natural selection.

The oak tree produces fewer acorns in random years in order to control the number of predators feeding on its seeds. The resulting die off of predators ensures the following year there will be increased chances of its seed taking root and producing a sapling. The process is referred to as "masting," and the hope in areas experiencing shortfalls is that this natural selection is all that's at play, and not something more sinister like climate change or undiagnosed pestilence.

"I know over the years if it was a real dry summer, you'd get less," said Hubley. "They don't produce acorns if they're in a weakened state. But I didn't see that this season because we had a lot of rain."

Maudslay Park Supervisor Rob Kovacs confirms a healthy crop of acorns this year coming from the oaks out at Newburyport's Maudslay Estate, and he's seen more than a few fat, happy-looking squirrels foraging on them, which would indicate a typical or banner year by standard.

"We did have a reasonable quantity of acorns and hickory nuts (this year)," said Kovacs yesterday. "There's been a lot of activity by the squirrels as well. I did not see a shortage of either."