Laser-induced fluorescence - A method to detect the vitality of Scots pines

Fluorescence,measurements were carried out with;, the ground-based DLidaR-2 of the German Aerospace Center (DLR) in October 1994 oz pine trees (Pinus sylvestris L.) located in two differently polluted areas of eastern Germany . The DLidaR-2 instrument is a far-field;fluorescence lidar exciting the le aves with a doubled or tripled air-cooled Nd:YAG laser The lidar is configu red as a coaxial system with variable beam divergence; irz front of the rec eiving telescope. The detection unit is set up with several channels equipp ed with; sensitive photomultiplier and interference and blocking filters fo r spectral separation. At two test sites (Neuglobsow, Rosa) as part of the SANA project, five nl-eas including three groups with five pine trees were selected Sor the fluorescence lidar measurements. At each area twigs in the zipper crown;iz of the 15 selected trees were cut. The young needles Ori r st needle age class) were prepared for pigment analysis (chlorophyll a and b), nutrition element analysis (e.g., Mg, K) and for the determination, of biochemical parameters (e.g., reduced glutnthione-GSH; glutathione reductas e-GLR; superoxide dismutase-SOD, and soluble protein-PROT. Additional tip n ecroses were estimated for both needle age classes. The results show that t he current year's needles from, the polluted site (Rosa) contain more SO4-S and antioxidants than those from nz the reference al-en (Neuglobsow ro). F or both test sites a correlation between the detoxification enzyme SOD and the chlorophyll fluorescence ratio (F685/F730) is observed (r=0.82) as well as for chlorophyll a and b concentration and the chlorophyll fluorescence ratio (r=0.82). The blue-green fluorescence ratio (F440/F520) is also corre lated with; damage symptoms as, Sor example, the needle damage index (r=0.8 3), which is derived from visual inspection of the needles. Taking into acc ount that the fluorescence lidar measurements present an average over diffe rent twigs; alzneedles of different age, it can be summarized that lidar-me asurements from the ground can yield useful information about the vitality; state of the trees. Therefore,Sere,differention between;een stressed and n onstressed trees is obvious. (C) Elsevier Science Inc., 1999.