US: A group of scientists from NASA, University of Maryland and Woods Hole Research Center created a unique map that shows height of the earth’s forests. The map, supposedly an accurate and high-resolution reading, has been created using LiDAR-based measurements from the Geoscience Laser Altimeter System instrument on NASA’s Ice, Cloud and land Elevation Satellite (ICESat).
The map, available at https://lidarradar.jpl.nasa.gov, depicts the highest points in the forest canopy. Its spatial resolution is 0.6 miles (1 kilometer). The map was validated against data from a network of nearly 70 ground sites around the world.
The researchers found that, in general, forest height decreases at higher elevations and are highest at low latitudes, decreasing in height the farther they are from the tropics. A major exception was found at around 40 degrees south latitude in southern temperate rainforests in Australia and New Zealand, where stands of eucalyptus, one of the world’s tallest flowering plants, tower much higher than 130 feet (40 meters).
The researchers augmented the ICESat data with other types of data to compensate for the sparse LiDAR data, the effects of topography and cloud cover. These included estimates of the percentage of global tree cover from NASA’s Moderate Resolution Imaging Spectroradiometer on NASA’s Terra satellite, elevation data from NASA’s Shuttle Radar Topography Mission, and temperature and precipitation maps from NASA’s Tropical Rainfall Measuring Mission and the WorldClim database. WorldClim is a set of freely available, high-resolution global climate data that can be used for mapping and spatial modeling.