Estimation of tree heights and stand volume using an airborne lidar system

The use of an airborne lidar system for estimating tree heights and stand volume was investigated. A helicopter-borne laser was tested in a coastal Scots pine stand where mean height was approximately 12.5 m. The laser equipment operated in a scanning mode and different laser footprints and sampling densities were tested at three independent registration times: one in June, one in October, and one in December. The tested footprints, measured at the ground, were between 0.75 m and 3.0 m in diameter. The results showed that the mean tree height was underestimated by 2.1–3.7 m. Optimal laser footprint size was found to change across data acquisition times.