The Internal Transfer of Nutrients in a Scots Pine Stand I. Biomass Components, Current Growth and their Nutrient Content

Abstract

The above-ground parts of ten sample trees in a 46-year-old Scots pine stand were analysed for dry-matter by age components and for nutrient content (N, P, K, Mg and Ca). Regression techniques were used to estimate stand parameters. Total above-ground biomass was 120.8 tonnes per hectare: 87.3 t bole, 20.7 t branch and 11.2 t needle. First year tissues at the end of 1976 were estimated at 17.1 t/ha: this total and, in particular, its wood component was almost certainly too high by 2–3 t/ha. Samples from 3 age-classes of needles and branches, 5 age-classes of bole wood and one each of bark and cones were analysed for nutrient content. The concentrations of N, P, K and Mg generally decreased with age while that of Ca increased. The living above-ground parts of the trees contained an estimated 332 kg N, 35 kg P, 212 kg K, 139 kg Ca and 46 kg Mg per hectare. Of these 115.2 kg N, 12.8 kg P, 62.1 kg K, 20.8 kg Ca and 9, 9 kg Mg occurred in first year tissues, representing the amounts used in the previous years growth. Approximately 14.5 kg N, 2.4 kg P, 17.4 kg K, 8.7 kg Ca and 3.3 kg Mg were estimated to have been retained in the biomass of the following year.