CONCORD, N.H. — Northeasterners who are digging deeper into their pockets to pay for firewood this season can add a new scapegoat to the roster of usual market forces: fracking.

Yep, a timber industry representative in New Hampshire said those hydraulic fracturing well sites in Pennsylvania’s Marcellus Shale formation to suck natural gas out of the ground are using construction “mats” made of hardwood logs — think of the corduroy roads seen in sepia-toned photographs from the 1800s — to get heavy equipment over mucky ground, wetlands or soft soils.

That increased demand has crept down the chimney into fireplaces. Prices in parts of New England are averaging $325 a cord and can even push past $400 for a seasoned, delivered load. That’s anywhere from $50 to $75 more a cord than last year — or an increase of 18 to 23 percent.

Jasen Stock, executive director of the New Hampshire Timberland Owners Association, said it’s not just fracking sites that are hogging the logs. Pipelines and transmission wires — really any large-scale construction project — have in the past three years ramped up the appetite for the perfect mat log: a hardwood trunk, 16 to 20 feet long and 8 to 10 inches in diameter.

As a result, the cost of cordwood on the stump (that is, live trees) went from $10 in 2012 in northern New Hampshire to $15 this year, Stock said.

“If you’re putting in a power line or gas line over wetlands or soft soil, they use thousands and thousands of these mats, and they’re made of hardwood logs,” Stock said. “If you’re in the firewood business, that’s your sweet spot. That’s the log you want.”

About 2.5 million households in the U.S. burned wood to keep warm in 2013, just 2.1 percent of total households but up from the 1.7 percent that stoked stoves in 2005, according to the U.S. census. The percentages get significantly higher in more heavily forested New England states like Vermont (16.3 percent), Maine (12.7) and New Hampshire (7.7), as well as the Pacific Northwest, including Idaho (7.8) and Oregon (7.1).

While New England shivered and shoveled through the winter whomping of 2014-15, the Pacific Northwest stayed mild, meaning more supply and steadier prices this year.

If the National Weather Service’s forecast of a warmer-than-average winter in New England holds up, that could mean fewer logs burned this winter, more robust stockpiles of seasoned wood come springtime and potentially lower prices next year. But it won’t help consumers who’ve already locked in their supplies this fall.

Other uses — pulp and paper mills still value hardwood and pellet producers and biomass plants also nibble on stockpiles — have also given loggers more markets.

“There’s only so much wood around,” said Jonathan Clark, owner of Treehugger Farms in Westmoreland, New Hampshire. The price for his kiln-dried cord went up $10 this season, to $360. Demand, he said, has stayed the same.

“Our calls started early this year and have continued steady,” he said. “Even now, we’re getting people who are having trouble getting their wood in.”

When oil prices started to bubble up, more people in the forest states saw wood as a desirable, locally sourced, cleaner and cheaper alternative. But even as heating oil prices tanked this year, wood got more expensive.

A few are even ditching firewood altogether.

“In a year where oil spikes, we just can’t crank the firewood out fast enough. But this just isn’t one of those years,” said Jeff Lemon from Four Seasons Firewood in Searsmont.

Some of the continued demand is likely coming from people who converted to woodstoves and are sticking with it. In Plainfield, Vermont, Donny Osman will heat his farmhouse with about six cords of wood this year at a cost of $230 each. Vermonters paid $180 a cord five years ago.

“I think that’s fairly reasonable, when you consider how much work goes into getting you a cord of wood,” said Osman, 68, who isn’t planning on switching fuels anytime soon.

“I would only do that if I couldn’t do it (handle wood) physically,” Osman said.

Contributing to this report were Associated Press reporters Dave Gram in Montpelier, Vermont, and David Sharp in Portland, Maine.