“If you wanted to create a perfect storm for biological invasion, you would do what the energy companies are doing in north-central Pennsylvania,” said Kevin Heatley, an ecologist with the national firm Biohabitats who works to restore areas that have been damaged by human activity. “You can only put so many bloody parking lots in the woods.”

Energy companies, which say they are being responsible stewards of the land, have rushed to unlock the natural gas lying in the shale beneath Pennsylvania, Ohio and West Virginia. The gas has lowered energy costs, allowed the U.S. to lessen reliance on foreign energy and provided private landowners who sit atop well sites with a gold mine in royalties. New York, which also has large reserves, is trying to decide whether to allow fracking.

The new energy development is “almost a spider web coming down to the forest,” said Nels Johnson of the Pennsylvania chapter of The Nature Conservancy, which estimates the state could see thousands of miles of new pipelines over the next two decades.

Even northeastern states that have put a hold on fracking aren’t immune, because many import natural gas. The U.S. Energy Information Administration found that 245 miles of new pipelines were laid in the Northeast last year, and that figure is projected to grow.

Wind turbine development poses similar threats, too. The Nature Conservancy says Pennsylvania already has more than 600 of the giant blades, with the potential for thousands more in coming decades.

The total acreage taken up by the pipelines, wind projects and related development isn’t that large, but the open spaces they create allow predators and invasive species to permeate a canopy of trees that once kept them at bay.