Distribution of biomass and carbon in even-aged stands of Norway spruce (Picea abies (L.) Karst.): A case study on spacing and thinning effects in northern Denmark

• Published in: Scandinavian journal of forest research 2006-12, Vol.21 (6), p.470-488
• Main Authors: Skovsgaard, J.P, Stupak, I, Vesterdal, L
• Format: Article
• Language: English
• Subjects: age structure; biomass expansion factor; Biomass expansion factor (BEF); biomass functions; branches; branchwood; carbon; carbon sequestration; dry matter; dry matter partitioning; equations; even-aged stands; foliage; forest soils; forest stands; forest thinning; forest trees; leaves; LULUCF; mathematical models; Picea abies; roots; soil carbon; spatial distribution; stand density; stand management; stems; stemwood; tree age; tree and stand measurements; tree growth; volume functions
• ISSN: 0282-7581; 1651-1891
• DOI: 10.1080/02827580601056268

The main objective of this case study was to explore the possible influence of forest management on the levels and distribution of biomass and carbon (C) in even-aged stands of Norway spruce [Picea abies (L.) Karst.] in Denmark. Data originated from a long-term thinning experiment and an adjacent spacing experiment at stand ages of 58 and 41 years, respectively. Biomass of 16 trees from different thinning and spacing treatments was measured or partly estimated, and soils were sampled for determination of C stocks. All trees in each plot were measured for stem diameter and some for total height, to allow for scaling-up results to stand-level estimates. For trees of similar size, foliage biomass tended to be higher in the spacing experiment, which was located on slightly more fertile land. Foliage biomass increased with increasing thinning grade, but the effect could not be separated from that of tree size. At stand level, foliage biomass tended to increase with increasing spacing as well as with increasing thinning grade. For branchwood, stems and roots (including below-ground stump), the biomass increased with increasing tree size and stand volume at tree and stand level, respectively, but no differences between stands, spacings or thinning grades were observed, apart from that expressed by tree size or stand volume. At stand level, C stocks of all biomass compartments decreased with increasing thinning grade, while the distribution between compartments was hardly influenced. The ratio between above-ground and stem biomass was about 1.21 at stand level, while the ratio between below- and above-ground biomass was about 0.17. Thinning influenced the C stock of the forest floor and mineral soil oppositely, resulting in no effect of thinning on total soil C.