Scientific Paper

Dry Matter and Nutrients in the Biomass of an Age Series of Pinus patula Plantations in the Usutu Forest, Swaziland

Published in: South African Forestry Journal
Volume 163, issue 1, 1992, pages: 5–11
DOI: 10.1080/00382167.1992.9629361
Author(s): A.R. MorrisUsutu Pulp Company Limited, SWAZILAND

Abstract

The dry matter and nutrient content of 11 stands of Pinus patula, one to 21 years old, were determined by field sampling. Treating these stands as an age series sample of a single yield class the pattern of accumulation with time was examined. At rotation age (17 years) the biomass contained 551 kg/ha N, 73 kg/ha P, 383 kg/ha K, 238 kg/ha Ca and 88 kg/ha Mg. Annual rates of nutrient accretion into biomass peaked at six to eight years, when the rate of canopy development was greatest. Changes in the mass of needles per hectare followed closely the pattern of dry matter accretion in the total biomass, peaking at 10 to 11 years. The influence of biomass accretion and harvest log removal of nutrients on productivity of the stand is discussed.

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