Abstract

The effects of thinning intensity on wood structure and chemistry of Norway spruce [Picea abies (L.) Karst.] have been studied in a long-term thinning experiment established in the 1960s in south-western Sweden. The experiment comprised datasets of unthinned control trees and trees of four thinning treatments, in which thinning operations of different intensities were carried out. These thinning operations were applied either once, three, or five times over the course of the stand rotation. Thinning intensities varied from 0% to 60% based on the stand basal area (BA) before thinning: (A) 5 x 20% (i.e., 20% of the BA removed five times); (B) 3 x 40% (i.e., 40% of the BA removed three times); (C) 1 x 60% (i.e., 60% of the BA removed once); and (D) 5 x 40% (i.e., 40% of the BA removed five times). Altogether 60 trees that were 67 years old were sampled 38 years after the treatment onset. Radial growth rate, wood density, tracheid properties, and the chemical composition of wood were studied in detail. All four thinning treatments increased growth rate and decreased wood density; however, treatment D showed the greatest change. Single, heavy thinning in treatment C resulted in unfavourable intra-stem variation in ring width and wood density. No significant differences in tracheid properties and wood chemistry were found between the treatments. We conclude that only a remarkable increase in growth rate would induce detrimental changes in tracheid properties and wood chemistry in the context of thinning.

Keywords

cellulose; extractives; lignin; nitrogen; tracheid properties; wood density

Published in

Holzforschung
2010, Volume: 64, number: 1, pages: 81-91

SLU Authors

• Nilsson, Urban

  • Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences
    

Associated SLU-program

SLU Future Forests


UKÄ Subject classification

Paper, Pulp and Fiber Technology


Publication identifier

DOI: https://doi.org/10.1515/HF.2010.013

Permanent link to this page (URI)

https://res.slu.se/id/publ/42396