Investigation of laser-induced fluorescence of several natural leaves for application to lidar vegetation monitoring.

The laser-induced fluorescence spectra of living leaves of seven different trees were investigated by using a 355-nm pulsed Nd:YAG laser. The shapes of the spectra (360-800 nm) varied depending on the season and growing conditions. Generally, red fluorescence (>650 nm) was larger during summer to autumn, which offers information on the activity of photosynthesis, and blue-green fluorescence (<650 nm) was relatively large in early summer and late autumn to winter, which offers information on the progress of growth and senescence. The spectral shapes also varied depending on the organic constituents inside the leaves. Separation of the spectra into their components was tried to identify the leaves' constituents. These basic data are indispensable for developing a vegetation-monitoring fluorescence lidar.