Laser-induced fluorescence in plants that are under normal and stress conditions is studied. Fluorescent properties of some plants upon the exposure to Xe–Cl-laser radiation at λ = 308 nm are analyzed under laboratory conditions. A stable relation between the recorded fluorescence signals and the chlorophyll content is found. Results of remote measurements of fluorescence signals from some trees under natural conditions are presented. Lidar sensing methods are shown to be applicable to reliable determination of species, as well as of the state of foliage or conifer of the trees.