Estimation of X-band scattering properties of tree components

An X-band FM-CW very-fine-range resolution scatterometer was used to acquire backscattering data for individual branches for a number of tree species. Using a model to describe the scattering source function and an experimental procedure for selected removal of plant parts, an estimation was made of η, the volume backscatter coefficient, and κ, the volume extinction coefficient. It is found that: (1) leaves are strong attenuators as well as scatterers; (2) the albedo (the ratio η/κ), at a given angle of incidence, is nearly independent of the tree type; (3) the tree limbs are good attenuators but rather poor scatterers; and (4) te albedo changes as a function of the angle of incidence and for deciduous trees is also a function of the season