The Amazon rainforest and Indonesia's peat swamps aren't the only places suffering from deforestation. On the mainland U.S., swaths of forests are steadily disappearing, too.
It's not just that we're losing trees. The forests themselves are growing farther and farther apart, researchers say.
A new study found that the average distance between forest patches increased by nearly 1,690 feet — or about 14 percent — between 1992 and 2001.
That's bad news for biodiversity.
Think of each forest patch as a sanctuary or transit hub for migratory animals and other species. When forests are closely knit together, the wildlife, plants and soil can share nutrients and thrive. When trees are few and far between, these connections break down.
"There are lots of studies that concentrate on how much forest is lost. We wanted to see how important is the forest that we're losing?" said Giorgos Mountrakis, an associate professor from the State University of New York (SUNY) College of Environmental Science and Forestry in Syracuse.
Image: Yang S, Mountrakis G (2017)
Mountrakis and Sheng Yang, a doctoral candidate at SUNY, co-authored the paper, which was published Wednesday in the journal PLOS ONE.
Nationwide, the U.S. has lost around 34,900 square miles — or nearly 3 percent — of its total forest cover since the 1990s. That's an area roughly the size of the state of Maine.
Based on that and other earlier research, Mountrakis and Yang initially expected that distances between forests hadn't grown by that much: about 33 feet over the 10-year period, according to their simulations.
But when they drilled down into the data, they found that average forest distances were 50 times bigger.
Mountrakis said the results were "eye-opening," especially since much of the forest loss happened in rural areas and on public lands — not near land-devouring cities or on private properties, as one might suspect.
Image: DAVID mcnew/Getty Images
He explained the idea of forest distances like this: If you have a 5-x-5-foot forest patch in the middle of a forest, and it disappears, the average distance between forests won't change by that much, since you still have all the surrounding forest. But if that same patch stands alone on the edge of a cornfield or a suburb, and then is chopped down, the distance to the next forest increases significantly.
The second scenario is playing out across the continental U.S. — particularly in the West, which has been ravaged by wildfires and tree-killing insects and diseases in recent decades.
Mountrakis said he and Yang are next studying what is driving these growing gaps between forest patches. They're also looking at how forest loss affects different demographics, along lines of income, education and race.
The PLOS ONE study was supported by the National Urban and Community Forestry Advisory Council and the McIntire Stennis Program, U.S. Forest Service.