Biomassauttag vid delkvistat sortiment i klen gallring

Sammanfattning: The purpose of this study was to estimate the removal of biomass in connection with thinning operations in young stands that are dominated by small diameter trees. The economy of such operations depends on the products generated as well as the performance of the harvesting systems. Conversion tables designed to predict the outcome based on harvesting method was another goal of this study. Removal of biomass affects the nutrient composition of the site. Therefore it is a purpose that this study will provide researchers with some variables that can be utilized when studying this aspect. Trees were harvested and divided into bunches based on diameter. Thus three fractions were created. Furthermore pine, spruce and birch were kept apart. Three methods of delimbing were utilized. (1)Bunches were kept and treated as such, (2) single trees were delimbed by breaking branches and (3) single trees were delimbed in a conventional way. It was established that small to medium diameter spruce bunches retained 30% - 36% more biomass than single trees delimbed separately. Pine and birch showed lower proportions. Among bunches with large diameters it was established that birch retained the largest proportion of biomass. The conversion tables provide some guidance when calculating costs and benefits in thinning young stands by different harvesting methods.