Wide Range Measurement of Surface Vegetation as Global Environment Asset and Development of Its Function Evaluation System

开发了一种全新的方法，利用航空激光测高获得的植被剖面来估算大面积的森林生物量和叶面积指数(LAI)，并建立了一个基于激光的地理信息系统森林调查系统，将这种面向环境的信息与现有的面向木材的信息和数据结合在一起。Ontakesan在本项目中，以及从其他来源为爱慕大学的实验森林和加拿大北部森林的600公里长的样带。还进行了一系列森林调查，以获得现有森林生物量和叶面积指数的地面真实情况。基于这些遥感数据和地面数据，开发了三种不同的从植被剖面反演森林生物量和叶面积指数的方法。第一种方法是基于剖面的傅里叶分析，得到功率谱，进而给出平均冠层直径作为对应于功率最大值的波长。其他重要的林分特征，如平均胸径、树高和尾部密度，然后从平均冠层直径得出，最终导致对林分蓄积量和生物量的估计。第二种方法是基于分子动力学中平均自由程的概念，给出了作为平均激光穿透深度的函数的叶片密度的估计，这与单叶的平均面积一起，得到了整个冠层的叶面积的估计，从而与叶面积指数相反。第三种方法用平均树高和树干密度的乘积来表示植被剖面与林分蓄积量之间的关系。

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.