Regional forest growth rates measured by combining ICESat GLAS and Landsat data

Abstract

Forest canopy heights derived from ICESat Geoscience Laser Altimeter System (GLAS) lidar data were combined with Landsat-based disturbance history maps to assess forest regeneration rates in three regions of the eastern United States (Maine, Virginia, and Mississippi). GLAS observations were screened for topographic relief and waveform quality, and canopy heights were obtained by visual inspection of each waveform. Regressing the GLAS heights against the age of last disturbance yielded vertical growth rates of 0.6 m/yr (Maine), 1.0 m/yr (Virginia), and 1.2 m/yr (Mississippi). Growth rates, when combined with height-biomass allometric relations, can be converted to estimates of aboveground wood productivity. The study demonstrates that large-footprint lidar data can be used to measure vertical growth rates when averaged spatially, thus providing unique information on forest regeneration for carbon cycle studies. Copyright 2009 by the American Geophysical Union.