Remote sensing of biophysical variables in boreal stands of Picea mariana

Using two hybrid radiative transfer models to represent conifer canopies and stands the authors develop and evaluate algorithms to infer several important structural parameters of stands of black spruce (Picea mariana), the most common boreal forest dominant. Using spectral mixture analysis and multispectral reflectance data for 31 black spruce stands of varying density and structure, the authors infer the values for the areal proportions of sunlit canopy, sunlit background and shadow fraction-they call radiometric elements-then show that the areal proportions of these radiometric elements are strongly related to leaf area index, biomass density and annual above ground net primary production. The best overall correlations between the radiometric elements and biophysical variables was shadow fraction obtained with the cone-based variable canopy reflectance model.