Laser scanning reveals bryophyte canopy structure

Abstract

• We evaluated laser scanning as a method to provide depth measurements for bryophyte canopies at fine spatial scales to derive surface roughness (Lr), a structural parameter. • Depths to the first vertical canopy contact were measured on 5 x 5 cm2 areas of 27 bryophyte canopies using a contact probe, a commercial laser scanner and a scanner employing a laser diode striper (LED scanner). Laser scanning adequately distinguished structural types, but scanner configuration led to differences in the magnitude of Lr. • LED scanning did not damage photosystem II function in three bryophyte species, Bazzania trilobata, Sphagnum girgensohnii and Pleurozium schreberi, as evidenced by no change in the chlorophyll fluorescence parameter FV/FM following LED scanning, but a decrease when subjected to high light. • A previously published boundary layer conductance model was parameterized with surface roughness values determined using a laser scanner and compared with the results obtained with contact probe measures. The resulting parameters of the functional models did not differ significantly from each other. © New Phytologist (2005).