Ståndortsanpassning och produktionspotential för björk i Gävleborgs län

Abstract: Large amounts of birch-timber are imported to Sweden, from particularly the Baltic States, since the domestic production can’t support the pulp industry. The goal of this study was to show the potential of birch and the area’s most suitable for birch production. The study was limited to Gävleborg County. Using site characteristics, site index (SI) for birch was estimated on all National Forest Inventory plots in Gävleborg County. Based on these estimations the site characteristics that gave the highest production for birch was found. To find the highest producing (m3sk ha-1 yr-1) birch sites in Gävleborg County and their size, a GIS-model divided in three classes was created. The birch production was also compared with the production-showing tree species (pine or spruce) on the plot to find the areas where birch best could match their production. The sites where birch had the highest production were low altitude and mesic sites with rich field layer type and slopes, in the southern parts of Gävleborg County. When birch was compared with pine and spruce, the sites where birch best could match their production were: low altitude and mesic sites with poor field layer type and slopes. Compared with pine, birch produced better in the southern parts of Gävleborg County, but that was not the case when comparing birch with spruce. The GIS-analysis showed that 15,4 % of all forested land qualified in class 1, the best class. In class 2, 57,4 % of the forested land was placed, and 27,2 % in class 3 with the lowest production.