Individual Tree LAI Inversion Technique Based on Stratification Theory and 3D Laser Scanning

Taking Litchi chinensis, Pinus massoniana and Pinus thunbergii as objects. LAI-2200 and Stonex X300 were used to obtain Leaf Area Index of isolate canopy (LAI_g), further to simulate Leaf Area Index of overall canopy (LAI_z). Simultaneously, the methods of planar projection, contour extraction and leaf angle correction were used to obtain Leaf Area Index of a layer (LAI_f) coupled stratification theory. The simulation accuracy of Leaf Area Index of single tree were verified by analyzing correlation among LAI_g, LAI_z and LAI_f. The results showed that the stratified vertical distribution of leaf area of single tree was consistent with the trend of vertical distribution profile of the canopy leaves. LAI_z of L.chinensis, P.sthunbergii and P.massoniana were 75.78%, 47.75% and 18.21% lower than LAI_f of them, respectively. There were a very high correlation between LAI_f and LAI_g, of which the correlation coefficient R² was 0.992 3. Therefore, coupled stratification theory and the three-dimensional laser scanning technology meet the needs of the investigation, which can provide important development method to comprehensive and multi-angle forest survey.