NASA Imagery Shows Trees are Dying in US Forests

Years of drought and high temperatures are thinning forests in the upper Great Lakes and the eastern United States. According to 2013 NASA satellite imagery which is part of the third National Climate Assessment, nearly 40 percent of Mid-Atlantic forests have lost tree canopy cover. Other afflicted areas include southern Appalachia, the southeastern coast and to a lesser extent, the Rocky Mountains and the Sierra Nevada.

The combination of less water and higher temperatures are making trees, especially southern pines and the upper Midwest’s hardwoods, more vulnerable to insects and new pathogens.

Climate change is impacting forests in several ways including increasing the risk of forest death through wildfires, insect infestations, drought, and disease outbreaks,

As part of a destructive feedback loop, tree losses will further exacerbate climate change. Trees absorb heat-trapping carbon dioxide emissions and thus can reduce the effects of climate change. According to the EPA in 2010, trees absorbed 13% of US emissions.

The NASA study is based on monthly satellite images which provides a more detailed picture of changes in forests, wetlands and grasslands over extended periods of time. The news from these images is not all bad, they also reveal that in the western parts of Alaska, higher temperatures have helped forests by expanding the growing season for trees.