NASA - National Aeronautics and Space Administration

A NASA-funded study shows that NASA satellite data can provide new details on forest growth and health, helping track the impacts of our changing planet.

Image right: A rain forest in the U.S. Pacific Northwest. Credit: National Park Service

Scientists using data from NASA's MODerate Imaging Spectroradiometer (MODIS) instrument aboard NASA's Terra and Aqua satellites found that measurements of forested regions across the United States often match those taken directly on the ground. The MODIS data also shows that the overall productivity of a forest is closely linked to the number of different tree species it contains, allowing scientists to more readily infer the effects of climate change on forests.

“In anticipation of shifts in climate, accurate measurements of forest growth and composition are becoming more important,” said Richard Waring, professor emeritus of forest science at Oregon State University, and lead author of the study. "The new data helps us better understand how forests may change so we can respond more efficiently."

Woody Turner, Program Scientist at NASA Headquarters, Washington, said "this research confirms that MODIS can provide detailed, accurate information on forests over vast regions in a simple, straightforward manner, essential for forest managers in a period of changing climate."

This study also used data from a country-wide survey of tree species provided by the Forest Inventory and Analysis dataset of the U.S. Department of Agriculture (USDA) Forest Service.

Image left: An image of evergreen conifers, a species common in the U.S. Pacific Northwest. Click to enlarge. Credit: National Park Service

Although forests appear to be adapting to changes in today's climate, prehistoric records indicate that climate change tends to destroy established vegetation patterns and causes new ones to be formed. "It is unclear how forests will respond in the future, when climate change is likely to become accelerated," said Waring.

But researchers are fairly certain there will be both winners and losers. New patterns of tree growth will emerge and while some species may die, others may simply migrate and thrive. Such changes to the landscape could in turn further modify the weather and climate. For instance, the atmosphere could warm if tree species like evergreen conifers move into areas that were previously treeless or snow-covered. This would reduce vegetation reflectivity, called albedo, causing more of the sun's energy to remain near the surface, raising temperatures.

Under another scenario, climate change might allow a greater number of tree species to grow in some forests, providing a natural defense against insect and disease attacks. But, some of the new species could be "invasive" and threaten the overall health of forests.

Image right: Global tree cover as measured by the NASA's MODerate Imaging Spectroradiometer (MODIS) instrument aboard NASA's Terra and Aqua satellites, showing areas with little or no tree cover (white shades) to considerable tree cover (green shades). Click image to enlarge. + High resolution image Credit: NASA/University of Maryland

While the impact of climate change on forest composition and health in the future remains unclear, research tools like MODIS are giving scientists the detailed information needed to better understand the various factors at play, vital for improved predictions and preparedness.

The study appears in the July 2006 issue of the journal Remote Sensing of Environment.

Related Links:

+ Additional images and information
+ MODIS satellite
+ USDA Forest Service Forest Inventory and Analysis
+ Story on Changing Forests

Mike Bettwy
Goddard Space Flight Center