Verification of the capability of repeat-pass SAR interferometry to provide tree height information in boreal forest zone

Abstract

A rather new aspect in SAR interferometry is the derivation of interferometric tree height over forested areas. This paper studied the impact of tree height and canopy closure on INSAR-derived terrain height in boreal forests. Previous studies in the field have suffered from the lack of good ground truth information, especially from the lack of canopy closure information, and, therefore, laser scanning measurements were used to generate DEM of the area, tree height and crown closure maps with a high accuracy (spatial resolution 0.5 m). The results imply that the impact of tree height was negligible on INSAR-derived DEM under winter conditions, and the capability of winter images to produce stem volume maps by the means of INSAR-derived tree height is probably impossible or, at least, limited. However, when pixels of equal characteristics were averaged instead of the near-by pixels, the effect of tree height and crown closure on the INSAR-derived DEM could be modelled and were found statistically significant.