ESTIMATION OF TEMPERATE FOREST CANOPY STRUCTURE USING LIDAR REMOTE SENSING AT XIAOXINGANLING, CHINA

Laser altimeter systems provide a direct measurement of canopy height, the vertical structure of vegetation and terrain elevation beneath the canopy. Over the past decade there have been dramatic improvements in lidar remote sensing technology which has been used successfully to estimate many forest parameters. This study uses data collected at Xiaoxinganling, a temperate forest in the Northeast of China, to investigate the potential of airborne lidar to estimate forest canopy structure and the effect of seasonality on estimates of height from GLAS data. High density small footprint lidar data and airborne hyperspectral data were collected over 300 km2 in September, 2009 and 126 systematic plots were measured in the summer of 2009. Forest canopy height, volume and biomass were estimated using airborne lidar and hyperspectral data and used to evaluate ICESat GLAS data collected during different seasons. The results show that summer period GLAS waveforms best capture returns from the forest canopy. Data from an early stage of autumn still contain returns from the forest canopy, although with lower intensity. The spring period and late autumn period data contain a weaker signal from the forest canopy and it is difficult to estimate forest height for them. This preliminary result will be helpful for appropriate period data selection to generate forest height maps for temperate forests. The Xiaoxinganling site will be used as an intensive forest biomass research site in China for future missions like NASA DESDYnI and ESA BIOMASS.