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Natural gas production is increasing faster in Pennsylvania than in any other state. Companies are using hydraulic fracturing to unlock vast amounts of gas in the Marcellus Shale. The state is no stranger to extractive industries, like timber. By the early 20th century its forests had been decimated. They've since been replenished and trees are now harvested sustainably. But scientists say this surge in gas development poses a new threat to the state's forests.
Marie Cusick of member station WITF reports.
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MARIE CUSICK, BYLINE: I'm standing on the side of a mountain road trying to avoid a steady stream of heavy truck traffic. Acres of freshly cut tree stumps stretch out in front of me.
KEVIN HEATLEY: This is up here in Tiadaghton State Forest. And you're looking at some of the impacts associated with forest fragmentation.
CUSICK: Kevin Heatley lives in the area and has come to these woods for years to hike. He's an ecologist by trade, who's concerned about what he's seeing. It's called forest fragmentation. And it's what happens when human development crisscrosses the landscape, carving up large swaths of contiguous forest into smaller pieces.
HEATLEY: Everything from the noise and the traffic, to the lighting, to the pad placements, to the pipeline construction, to the road expansion, this is all industrial infrastructure. It's inherently incompatible with sustainable forest management.
CUSICK: Here in Lycoming County, a heavily-wooded part of North-Central Pennsylvania, the U.S. Geological Survey has found that most of the disturbance from gas drilling is happening in sensitive ecosystems, known as core forests.
HEATLEY: And that is forest next to forest.
CUSICK: It's very different from so-called edge habitats - that's forest next to something else, like a grassy field or a suburban home. Big tracts of core forests are rarer and they're home to species that don't do well near people.
Margaret Brittingham is a professor at Penn State University who's also studied forest fragmentation. She says when core forest is lost, so are the host of important services its plant and animal species provide.
MARGARET BRITTINGHAM: Insect control, climate control, water purification, you can go on and on - recreation, aesthetics.
CUSICK: Pennsylvania currently has roughly two million acres of public forest land. About a third of it is available for drilling.
ROB BOULWARE: We are probably currently one of the largest and more active drillers in state forest lands in Pennsylvania.
CUSICK: Rob Boulware is a spokesman for Seneca Resources. He says his company works to minimize forest fragmentation. For example, it tries to use existing roads instead of building new ones. He points out though other industries cut down plenty of trees too.
BOULWARE: If it is a concern we are engaged in this activity that we are engaged in as humans and not just the activity that's being engaged in through the oil and gas industry.
CUSICK: But the gas industry is pushing a new measure that may lead to more forest fragmentation. Drillers are backing a controversial bill that would limit the authority of state agencies to designate endangered species. Boulware argues it's a matter of consistency for businesses. For example, he says companies are sometimes required to conduct expensive and duplicative wildlife surveys before they can begin drilling.
BOULWARE: These are little things that companies are looking for that would be cost-savings for each individual, and that's what you don't have with the current system.
CUSICK: Republican State Representative Jeff Pyle sponsors the bill. He says the agencies involved in endangered species designations shouldn't hinder economic development.
STATE REPRESENTATIVE JEFF PYLE: Their mission is to protect the game species of Pennsylvania. And me, as a legislator, part of my mission is to make sure my people don't see widespread unemployment.
CUSICK: As the pace of Pennsylvania's gas production continues to surge, energy markets will dictate how much development occurs. The key question is how much disturbance forests can withstand. It's a question scientists are still trying to answer.
For NPR News, I'm Marie Cusick.
CORNISH: This story comes from StateImpact Pennsylvania, a public radio reporting project focusing on Pennsylvania's energy economy.
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