Abstract

The spatial distribution of trees above ground influences on the amount of root biomass and a low root biomass might decrease the total biomass production. The amount of biomass for fractions and distribution of downy and silver birch root systems was studied including the root distribution in cardinal points. The allometric relationship between stump diameter (DSH) and stump weight and between DSH and root weight and length for the two species was quantified. The 12-year-old trees had been grown at four spacings on two sites: medium clay and fine sand soils. The dry root weight per stump differed significantly between species and spacings, but not for diameter class >5 mm and spacings. For both species the root weight was greatest at a spacing of 2.6 m on medium clay soil. The differences between cardinal points and root weight and length for all diameter classes and both birch species were not significant. Equations for estimating the stump weight, root weight and the root length from diameter at stump height (DSH) confirmed that DSH can be used as a simple variable to estimate the root biomass. Equations for estimating root biomass by DSH or diameter at breast height (DBH) is presented

Keywords

Betula pendula; Betula pubescens; Biomass eq1uation; Root biomass; Soil types; Spacing

Published in

Report / Department of Energy and Tecnology, SLU
2009, number: 014
Publisher: Sveriges lantbruksuniversitet, Institutionen för energi och teknik

Authors' information