THE CHEMICAL-COMPOSITION OF NEEDLE AND LEAF-LITTER FROM SCOTS PINE, NORWAY SPRUCE AND WHITE BIRCH IN SCANDINAVIAN FORESTS

Needle litter from 14 stands of Scots pine (Pinus silvestris, L.), 13 stands of Norway spruce (Picea abies it.) Karst.) and leaf litter from three stands of white birch (Betula pubescens Ehrh.) were analysed fo r chemical composition. The concentrations of the elements N, P, K, Ca , Mg and Mn as well as solid organic components (lignin, cellulose and hemicelluloses) and solubles were determined. When the average chemic al compositions were compared the Scots pine needle litter was clearly the most nutrient-poor litter type. Of the solid organic-chemical com ponents the lignin fraction dominated in the spruce and birch litter w hereas the cellulose dominated in the pine needle litter. When Norway spruce and Scots pine were growing in adjacent stands on soils with th e same bedrock origin the spruce litter had significantly higher conce ntrations of nutrients (N, P, K, Ca, Mg, Mn) than the pine needle litt er. At sites where Norway spruce and white birch were growing in adjac ent stands, the birch leaf litter had generally higher concentrations of nutrients. However, significant or nearly significant differences w ere only obtained for Mg (P = 0.002), K (P = 0.056) and N (P = 0.087), probably due to the few replicates of stands compared. Concerning org anic chemical components, the spruce needle litter had significantly h igher concentrations of lignin and mannan than all the other litters a nd lower levels of ethanol-soluble substances, cellulose and galactan than the pine needle litter. Further, it had lower concentrations of w ater solubles, rhamnan and xylan than the birch litter. No relationshi ps were established between the nutrient status of the conifer litters and the site index H100 (the dominant height of the trees at a refere nce age of 100 years) of the stands. Concentrations of solid carbohydr ates in the litters were, however, positively correlated with site ind ex (P < 0.001). Further, the concentration of nitrogen in the pine nee dle litter was negatively correlated with the latitude of the sites (P < 0.01). The influence of litter chemistry on the decomposition of li tter and nutrient cycling of forests is discussed.