%0 Research article
%T Comparison of boom-corridor thinning and thinning from below harvesting methods in young dense Scots pine stands
%A Bergström, Dan
%A Bergsten, Urban
%A Nordfjell, Tomas
%D 2010
%J Silva Fennica
%V 44
%N 4
%R doi:10.14214/sf.134
%U https://silvafennica.fi/article/134
%X At present, only a small proportion of the potential extractable  bioenergy from young dense forests in Sweden is utilized. The  conventional mechanized first thinning systems used in such stands  suffer from low productivity, so the operation is only profitable in  stands with bigger trees and high standing volumes. Conventional  harvesters are used for this operation equipped with accumulating  felling heads designed for handling several trees during each crane  cycle. In thinning from below the felling and bunching work requires  many time-consuming non-linear crane movements to avoid felling or  damaging of future crop trees. However, higher productivity can be  achieved when trees between strip roads are harvested in about 1 m-wide  corridors with a length corresponding to the reach of the crane. We  refer to this operation as boom-corridor thinning. The objective of this  study was to compare felling and bunching productivity in young dense  stands when employing thinning from below or boom-corridor thinning.  Experiments were performed using a randomized block design involving  between 4400 and 18 600 trees x ha<sup>-1</sup> with a corresponding  average tree size of 7.2 and 3.2 cm dbh, respectively. Based on the  average tree being removed at a dbh of 5.7 cm, the productivity (ODt x  PW-hour<sup>-1</sup>) was significant (almost 16%) higher for the  boom-corridor thinning than for thinning from below treatment. At the  same time, the time taken for the work element “Crane in-between” (the  period between the loaded crane starting to move towards a tree and the  felling head rapidly slowing down for positioning) was significantly  reduced, by almost 17%. The positive results were achieved even though  the operator was new to the method. To achieve a significantly higher  efficiency during the felling and bunching operation, development of new  harvesting equipment and operating techniques seems crucial.