NASA is currently producing a new type of map of the world’s forests, using satellite-based laser technology. It is intended to measure forest height and density around the world, in order to study the extent to which forests function as carbon “traps” or storage, and may therefore help limit the effects on the world’s climate of increasing carbon emissions.
According to NASA’s Earth Observatory program, three of the agency’s Earth reconnaissance and research satellites were tasked with developing the new map: Terra, Aqua, and ICE Sat. It produced a global map of forest heights, predictably finding that the tallest trees are in northwestern North America (along the Pacific coast) and southeast Asia. In order to fill out the map, the satellites produced average heights of trees in specific forest regions, rather than measuring maximum and minimum tree heights.
The three satellites involved in the forest mapping project are not specialized for this purpose – rather, it is just one component of their continuing missions in orbit. When ICE Sat was first launched in 2003, it was intended to study ice sheets and cloud weather. (ICE Sat’s monitoring systems crashed in early 2010, and the satellite is now considered dead.) Aqua was intended as a water and atmosphere research project. The oldest of the three, the decade-old Terra satellite, was designed to study clouds and air pollution.
The fact that the tallest forests were found in parts of Eastern Asia and Pacific North America was not the surprising part: scientists (and sightseers) were already quite well aware that the towering species of those areas, in particular redwood and Douglas fir, grew markedly higher than the dominant tree species of other regions, like pine and spruce trees. Instead, what scientists hope to gain from the new space laser map of the world’s forests is an understanding of how much carbon the world’s forests can store, and how that storage occurs. Overall, about two billion of tons of carbon are believed to be absorbed by the world’s forests, accounting for a meaningful minority of human emissions. (That which doesn’t end up in forests ends up in the atmosphere, or absorbed into the ocean.)
However, now that the map has been created, it will likely turn out to have many other purposes as well, such as analysis of forest fire patterns. For instance, in June 2010 NASA announced that is also using its forest database to help ornithologists study bird species by identifying areas with the greatest forest canopies, which are home to many bird species. NASA is making its forest mapping available to the public; for instance, forest canopy heights in America are visible on a special map here.