Crown level clumping in Norway spruce from terrestrial laser scanning measurements

The clumping of coniferous needles into shoots is widely acknowledged as a structural feature that cannot be ignored in radiation regime models forests. However, higher level clumping, i.e. the aggregation leaves and tree crowns forest stands, still rarely accounted for models. Clumping reduces light interception increases penetration depth plant stand. To improve with respect to this parameter, we propose method can quantify at different hierarchical levels by estimating silhouette total area ratio from point clouds acquired laser scanners. Our based on attenuation coefficients voxel grid, subsequently computing leaf spherically averaged crown or We tested our empirical data young Norway spruce trees, where compared destructive photogrammetric reference measurements. accuracy estimates depended strongly size, sizes below 10 cm side length exhibiting up 100% than area, large voxels 90 being closest measurements due clumping. varied less size were slightly estimates. analyzed possible error sources out ways conifer trees using scanning data.