Airborne laser scanning as a method in operational forest inventory: Status of accuracy assessments accomplished in Scandinavia

This research reports the major evaluation results from an operational stand-based forest inventory using airborne laser scanner data carried out in Norway. This is the first operational inventory in which data from two separate districts are combined. Laser data from two forest areas of 65 and 110 km(2) were used to predict six biophysical stand variables used in forest planning. The predictions were based on regression equations estimated from 250 m(2) field training plots distributed systematically throughout the two forest areas. Test plots with a size of 0.1 ha were used for validation. The testing revealed standard deviations between ground-truth values and predicted values of 0.58-0.85 m (3.4-5.6%) for mean and dominant heights, 2.62-2.87 m(2) ha(-1) ( 9.3-14.3%) for basal area, and 18.7-25.1 m(3) ha(-1) (10.8-12.8%) for stand volume. No serious bias was detected. For 10 of the 12 estimated regression models there were no significant effects of district.