Biomass and nutrient accumulation by tree components for 66-year-old mature paper birch is presented. Logarithmic regression equations are given relating aboveground tree component biomass and contents of N, P, K, Ca, and Mg to tree diameter at breast height (dbh). Branches, bole bark, and bole wood accounted for 90–97% of the total aboveground tree biomass. Highest concentrations of most nutrients were in the foliage. For the tree of mean basal area (dbh = 15 cm), the crown components of branches and foliage constituted only 16% of the biomass but accounted for 49, 57, 53, 37, and 44%, respectively, of the N, P, K, Ca, and Mg accumulated.