Biosims — a method for the calculation of woody biomass for fuel in Sweden

Abstract A planning model and a computer programme, ‘Biosims’, have been developed. A test of the model was conducted in Dalarna (Kopparberg), Sweden, in 1994. Modified ecological restrictions were tested using the current ecological restrictions as a reference. Recycling of wood ash was assumed to be a standard method. The results show that 24–56% of the total forest land area is affected by the ecological restrictions in the county of Dalarna. Translation of these results to woody biomass quantities shows that the total ecological potential of woody biomass for fuel is 20.5 PJ per year. The total use of woody biomass for fuel is 3.3 PJ per year. The remaining potential of woody biomass for fuel in the county of Dalarna is 17.2 PJ per year. The method uses stand data or sample plot data from the National Forest Survey (NFS). A method for application of ecological restrictions has been used. These restrictions are based on variables, e.g. soil and vegetation classes, included in the NFS-data. Two methods for woody biomass calculations are used: (1) the biomass functions for the main domestic tree species ( Pinus silvestris, Picea abies, Betula pubescens, Betula verrucosa ); and (2) the ratio method based on forest inventory data and conversion factors or functions between stand variables. The woody biomass is measured as oven dry weight per unit area. The results can be transformed, e.g. into energy equivalents and biomass nitrogen content. Different assumptions, such as heat value and moisture content, can be programmed and various technical and ecological restrictions can be imposed. The results can be presented in the GIS.