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 (ρ_RED), near-infrared (ρ_NIR ), and infrared (ρ_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 ρ_RED; almost no significant change in ρ_NIR ; and over 20% increase in ρ_IR. However, ρ_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 ρ_NIR which is not likely due to moisture variations