Abstract

In a stand with planted Norway spruce (Picea abies (L.) Karst.) and naturally regenerated birch (Betula pendula Roth and B. pubescens Ehrh.) in southern Sweden, the proportion of birch was reduced in 0.1-ha plots at pre-commercial thinning to 0%, 20% or 50% of the total stem number (2000-2500 stems ha(-1) after the thinning). The growth of both species was surveyed 4 and 10 years later. No significant between-treatment differences were observed on either occasion in total yield or in spruce diameter (apart from a more negative skewness of the diameter distribution of Norway spruce in the mixture with 50% birch compared to pure spruce). Birch retained its initial advantage in dominant height (of about 2 m) throughout the 10-year measurement period; hence, height growth rates of Norway spruce and birch were very similar. After three, four and 10 growing seasons, whipping damage to Norway spruce caused by birch was registered in the 20% and 50% birch mixtures, in which the proportions of damaged spruces were found to be similar, with 17% and 15% of damaged trees at the last inventory, respectively. In addition, simulations of the stands' development from the time of the last measurement until final felling at a total age of 66 years indicated that growth, yield and net present value decrease with increasing birch proportion, but if the proportion of birch removed in subsequent thinnings is increased, the between-treatment differences are reduced.

Keywords

Picea abies; Betula spp.; mixed stands; yield; whipping damage; economic outcome

Published in

Scandinavian Journal of Forest Research
2011, Volume: 26, number: 11, pages: 36-45
Publisher: TAYLOR & FRANCIS AS

SLU Authors

• Fahlvik, Nils

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

• Agestam, Eric

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

• Ekö, Per-Magnus

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

Associated SLU-program

SLU Future Forests


Sustainable Development Goals

Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


UKÄ Subject classification

Forest Science


Publication identifier

DOI: https://doi.org/10.1080/02827581.2011.564388

Permanent link to this page (URI)

https://res.slu.se/id/publ/58780