Applicability of airborne profiling radar to forest inventory

In this work the applicability of airborne profiling radar to forest inventory was studied in detail. The radar stand profiles were collected by using a helicopter-borne ranging scatterometer, HUTSCAT (Helsinki University of Technology SCATterometer), which can probe the forest canopy from the top to the bottom due to its ranging capability. Several radar variables were analyzed from stand profiles, and compared with field-measured characteristics of 20 m by 20 m sample plots, by applying multivariate data analysis methods. It was shown that mean and dominant heights, height of the crown base line, and stem volume per hectare can be obtained with good accuracy. Furthermore, the ranging radar can measure mean and dominant tree heights more accurately than is usually obtained with conventional field measurements. As possible direct application, it is proposed that radar measurements would be employed with helicopter-borne ocular inventories in order to improve the estimation accuracy and to speed up the measurements.