Plant Biomass, Primary Production and Bioelements of Three Mature Beech Forests in South Sweden

Abstract

Three mature forests representing a vegetational gradient of south Swedish beech forests are described in terms of the distribution or organic matter and bioelements. Biomass and primary production were estimated from allometric regressions made on sampled trees. Biomass of Mercurialis, Lamium and Deschampsia-types, was 358, 375 and 263 tonne ha-1, respectively. Corresponding total primary production was 19.0, 17.8 and 12.3 tonne ha-1, and the aboveground production was 16.7, 15.4 and 10.6 tonne ha-1 yr-1, with yearly increments in biomass estimated at 10.8, 11.0 and 7.1 tonne ha-1 yr-1. There was a relative increase of the root system in the high-low productivity gradient. Soil variables such as organic matter, N, nitrification rate, C/N-ratio, pH, amount of exchangeable nutrients and soil water change along the gradient and affected the chemical composition of the trees. N and K in the current twigs were positively correlated with primary production, but there was a negative correlation for P, Si and Mn. Decomposition rates and transformation factors for most elements are decreasing along the high-low productivity gradient. A general allometric regression equation, with diameter and height as independant variables, seems capable of describing the total plant biomass of both high and low-productivity beech forests in south Sweden.