Hyperspectral remote sensing of sagebrush canopy nitrogen

Plant canopy nitrogen (N) is associated with ecosystem processes such as photosynthetic and aboveground net primary production, particularly in forested ecosystems. Sagebrush N is directly relatable to wildlife nutritional status and contributes to assessments of habitat quality, productivity, plant / soil water dynamics and controls on canopy photosynthesis. Hyperspectral remote sensing studies have successfully estimated biochemicals under closed canopy conditions; however, more studies are needed to assess potential in sparsely vegetated shrub environments. Spectroscopic measurements of individual sagebrush shrub canopies collected in the field are relatable to foliar N concentrations analyzed in the laboratory. Encouraging results at the shrub scale warranted extension of the study to an airborne platform, whereby sagebrush canopy N concentrations are estimated across a landscape. Challenges include leaf water content, soil reflectance, and leaf angles, all of which can dampen or mask absorption features of interest.