Chemical composition and gross calorific value of the above-ground biomass components of young Picea abies

Fertilization is used to increase the total yield of biomass on a site, as well as sustaining or improving the health, vigour and vitality of trees. How fertilization affects the chemical composition and the fuel characteristics is poorly known. Extractives, lignin, holocellulose, ash content and calorific heat value were measured in the stem wood at the root (0 m), 2 m and 4 m levels, in the branches, and in the bark of young Norway spruce [ Picea abies ( L.) Karst.] trees. Ten control trees and six fertilized trees were evaluated. Fertilization with a balanced nutrient mixture had only a minor effect on the detected chemical and fuel parameters. The main differences in chemical composition within the tree were found between stem, branches and bark. Thus, fertilization can be recommended as a silvicultural treatment to increase the net biomass production on a site intended for fuel production.