Declining Forests In The Eastern United States As Seen From Space

Trends in forest canopy green cover over the eastern United States from 2000 to 2010 derived from NASA MODIS satellite sensor data. Green shades indicate a positive trend of increasing growing season green cover, whereas brown shades indicate a negative trend of decreasing growing season green cover. Image Credit: NASA


Forests in the eastern United States have become less green over the past decade.  That’s what scientists at NASA have concluded after analyzing a series of satellite images compiled between 2000 and 2010.  The scientists reviewed monthly images taken by NASA’s Terra satellite in four regions – the Upper Great Lakes, southern Appalachian, mid-Atlantic, and southeastern Coastal Plain – and found a significant decline in forest canopy cover.

The culprits?  Rising temperatures, changes in local and regional precipitation, and stressors that include insect pest outbreaks and the introduction of new pathogens.

In the past, researchers have had to rely on small-scale field site measurements, which made it difficult to understand widespread changes in forest growth.  But thanks to new technology that has allowed them to compile a decade of “baseline” data, they are developing a much clearer picture of how climate change is affecting these regions.

“This comprehensive data set gave us the evidence to conclude that a series of relatively dry years since 2000 has been unfavorable for vigorous growth of forest cover over much of the eastern U. S. this past decade,” said Christopher Potter, a research scientist at NASA’s Ames Research Center, who wrote a paper on the findings.  He says further research will be done to study the areas most affected by drought.

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