Microwave remote sensing for forest monitoring purposes

The study aimed to evaluate the capacities of imaging shortwave radar systems for forest monitoring studies and to develop a method for the analysis of a timeseries of radar images. A multitemporal set of X- and C-band airborne radar data, from a deciduous forest site in Flevoland (Horsterwold), was available for the purpose of the study. Topographic information was used in conjunction with the radar images in order to facilitate the extraction of radar data for individual forest stands. In X- as well as C-band the overall range of stand-averaged backscatter values was in the order of a few dB. The backscatter values appeared to be primarily dependent on incidence angle and species. In addition there is evidence of a relationship between backscatter and crown coverage. Stands with a relatively low degree of crown closure, e.g. recently thinned stands, young stands, etc., showed a decreased radar backscatter.