The reflectance of Pleurozium scheberi as a function of water status and its implications on understory reflectance variations for BOREAS sites

A controlled laboratory experiment was conducted to test the null hypothesis that the nadir reflectance of Pleurozium scheberi (a feather moss) in the red (/spl rho//sub RED/), near-infrared (/spl rho//sub NIR/), and infrared (/spl rho//sub IR/) bands is not a function of live layer moisture content. Reflectance spectra were acquired from replicate moss turves over five dry down stages ranging from 4.8 g water/g moss to 0 g/g. Replicate spectra showed a maximum 13.5% increase in /spl rho//sub RED/; almost no significant change in /spl rho//sub NIR/; and over 20% increase in /spl rho//sub IR/. However, /spl rho//sub RED/ variations due to drying before desiccation were less than 2%. Inter-replicate differences in reflectance were often larger than dry down differences. NIR understory reflectance measured in a moss dominated BOREAS site showed a significant seasonal change in /spl rho//sub NIR/ which is not likely due to moisture variations.