Comparing the characteristics of boom-corridor and selectively thinned stands of Scots pine and birch

Abstract

Young, dense forest in Finland and Sweden urgently need to receive first thinning. In such stands, conventional selective thinning methods make the harvester work time consuming and, thus, costly. To make small-sized trees economically competitive as raw material for bioenergy and biorefining, new harvesting technologies and/or thinning methods need to be developed. A potential solution is boom-corridor thinning (BCT), rendering effective cutting work. The aim of this study was to describe and compare the stand structure of two Scots pine stands ( L.) and one birch-dominated ( Roth with natural downy birch, Ehrh.) stand after BCT and selective thinning at the first thinning phase. Furthermore, simulations were conducted to predict the future stand development after the first thinning treatments. The density of the growing stock was 16–46% higher after BCT treatment than after selective thinning because BCT stands included more small and supressed trees with a dbh < 100 mm. However, the numbers of future crop trees with a dbh > 140 mm per hectare were at the same level in both treatments. The stem volume removal per hectare did not differ between treatments. However, simulation of stand development and intermediate thinning and clearcutting revealed that the total removal volume was 10–18% higher in BCT stands compared to selectively thinned ones. The saw log volumes harvested did, however, not differ between treatments. This study shows that BCT generates stands with higher biodiversity compared to conventional thinning as higher levels of biomass removal can be reached throughout stand rotations.Pinus sylvestrisBetula pendulaB. pubescens