Stem Quality and Height Development in a Betula-Dominated Stand Seven Years After Precommercial Thinning at Different Stump Heights
Abstract:Topping may provide an attractive alternative to traditional precommercial thinning, offering several advantages. The main stem quality of birch (Betula pubescens Ehrh. and Betula pendula Roth, species not separated) was examined seven growing seasons after such topping in a dense, even-aged and naturally regenerated stand in northern Sweden. The height development and survival of main and secondary stems of birch and secondary stems of willow (Salix spp.) were also studied. At a main stem height of 1.8 m, the following treatments, leaving 3100 main stems ha−1, were applied to secondary stems: traditional precommercial thinning (cutting just above ground), top-cutting at either 40% (71 cm above ground) or 70% (120 cm above ground) of main stem mean height, and no precommercial thinning. For main stems, topping resulted in fewer forks, straighter stems, higher live crown height and smaller diameter of the thickest branch compared with traditional precommercial thinning. In these respects, topping at the higher level above ground gave the best quality. The main stems were no longer at risk of becoming overtopped by the secondary stems following any of these treatments (except for no precommercial thinning).
Document Type: Research Article
Publication date: January 1, 2003