KIDA Hideki Kyoto University, Graduate School of Science Professor, 理学部, 教授 (60252417)
KOJIMA Satoru Tokyo Women's University, Dept. of Arts and Science Professor, 理学部, 教授 (80115138)
OIKAWA Takehisa Tsukuba University, Dept. of Biological Sciences Professor, 生物科学系, 教授 (70011682)
ISHIBASHI Seiji Tokyo University of Agriculture and Technology, Dept. of Forest Science Associate Professor, 農学部, 助教授 (30212921)
FUKUSHIMA Yoshihiro Institute for Hydrological and Atmospheric Science Professor, 大気水圏科学研究所, 教授 (00026402)
Entirely new methods of estimating forest biomass and leaf area index (LAI) over an extensive area from vegetation profile obtained by airborne laser altimetry were developed, and a laser-based GIS forest inventory system was established to accommodate such environment-oriented information along with the existing timber-oriented information and data.
The vegetation profile data, which constitutes the basis of the research, was obtained by a flight over the Mt. Ontakesan in the present project, as well as from other sources for the Experimental Forest of Ehime University and for a 600km long transect over the boreal forest of Canada. Also a series of forest inventory surveys was conducted to obtain ground truth for existing forest biomass and LAI. Based on these remotely sensed and ground data, three different methods of deducing forest biomass and LAI from the vegetation profile were developed. The first method is based on the Fourier analysis of the profile, which yields power spectrum, which further in turn gives the mean canopy diameter as the wavelength corresponding to the power maxima. Other important stand characteristics such as mean DBH, tree height and stern density are then derived from the mean canopy diameter, eventually leading to estimates of stand stocking and biomass. The second method is based on the notion of the mean free path in molecular kinetics and gives an estimate of leaf density as a function of the mean laser penetration depth into the foliage, which along with the mean area of a single leaf, results in an estimate of entire leaf area of the canopy anti thus the LAI. The last method correlates the integration of the vegetation profile with stand stocking, which is well represented by the product of mean tree height and stem density.