In World Forests, Patterns Matter

Posted by Jeff on Nov 8, 2015 @ 8:42 am in Conservation | 0 comments | Last modified: November 8, 2015

Between 2000 and 2012, the world lost forest area and gained forest area. But the losses exceeded the gains, according to U.S. Forest Service researchers and partners who compared tree cover data from those years and estimated a global net loss of 1.71 million square kilometers of forest — an area about two and a half times the size of Texas. That’s only part of the story, though.

“In addition to the direct loss of forest, there was a widespread shift of the remaining global forest to a more fragmented condition,” says Kurt Riitters, a research ecologist and team leader with the Eastern Forest Environmental Threat Assessment Center and the lead author of a study describing the phenomenon, recently published in the journal Landscape Ecology. “Forest area loss alone underestimates ecological risks from forest fragmentation. The spatial pattern of forest is important because the same area of forest can be arranged in different ways on the landscape with important consequences for ecosystem processes.”

To understand where risks from forest fragmentation might be greatest, the researchers evaluated the loss of interior forest — core areas that, when intact, maintain critical habitat and ecological functions. (In contrast, non-interior forest edge areas are subject to impacts from invasive species, pollution, and variation in soil moisture, for example.) Using global tree cover data, researchers mapped the forests of 2000 and 2012 and examined the patterns of change across ecological regions and biomes. Their analysis revealed a net loss of 3.76 million square kilometers of interior forest area, or about ten percent of interior forest — more than twice the global net loss of forest area. The rate at which interior forest area was lost was more than three times the rate of global forest area loss.

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