Polarimetric reflectance and depolarization ratio from several tree species using a multiwavelength polarimetric lidar

There is a growing interest toward using lidar for forest remote sensing. The Multiwavelength Airborne Polarimetric Lidar (MAPL) was designed primarily for vegetation remote sensing purposes. The system has full lidar waveform capture and polarimetric measurement capabilities at 532-nm and 1064-nm wavelengths. To study the polarimetric reflectance from different tree species, ground experiments were conducted using the MAPL system. Three tree canopies with distinct features were selected for this study. These are cottonwood (Populus deltoides), black willow (Salix nigra) and red-cedar (Juniperus virginiana). The test results revealed that the shapes of the lidar waveforms, the depolarization ratios, and the percent reflectance data all have distinct features for different tree species. The MAPL system is proved to be able to detect all these features. Our study indicates that the MAPL data have the potential to be used toward developing a tree species discrimination algorithm. In addition, it is also believed that these data can be used to detect tree stress conditions.