Comparison of leaf area density measured by laser range finder and stratified clipping method

Leaf area density (LAD) have an important role in biomass productivity models, radiative transfer studies, remotely sensed data and so on. In this study, the vertical profile of leaf area density (LAD) was measured by the laser range finder, which is the instrument to measure three dimensional coordinate. LAD was calculated by the method of NORMAN & CAMPBELL 1989 from gap fraction which is the probability of light passing through the canopy. In order to measure the vertical profile of LAD, gap fraction in horizontal layer divided into the canopy can be measured by the laser range finder. The vertical profile of LAD was compared with LAD measured by the stratified clipping method in two different-aged Japaneses larch forests, one is 5-year-old and another is 47-year-old. In 5-year-old forest, high correlation was seen in LAD between both methods (R²=0.94) and slope of regression equation is about 1.00. In the vertical profile of LAD, both method was shown that the maximum LAD in the layer from 1.0 m to 2.0 m and LAD decreased toward the upper and lower layer. In 47-year-old forest, LAD measured by laser range finder was underestimated by LAD measured by the stratified clipping method. In the profile of LAD, both methods were shown that the maximum LAD in the layer from 11.3 m to 13.3 m, but high LAD in the lower layer than 5m height was seen in the method of laser range finder. The cause of this difference is considered that only larch was measured by the stratified clipping method, on the other hand, low trees or shrubs were measured by the laser range finder. Consequenty, by using the laser range finder, it was possible to measure the vertical profile of LAD at the understory of forest.