The use of the Global Positioning System for effective forest inventory and management-experiences from the Swedish boreal forest zone

Two experiments with differential GPS were organized in northern Sweden. The first study was organized as helicopter flights along lines with known positions. Obtained GPS coordinates corresponded to a mean deviation of a few metres and a standard deviation of about the same size. This was judged to be satisfactory for navigation purposes in connection with forest fertilization or liming. In the second study the accuracy of repeated measurements for estimation of coordinates of sample plots in forested terrain resulted in standard deviations of a few metres. Stand boundaries were mapped with accuracy sufficient for maps on the scale of 1:20000, also under closed canopy