Produktivitet och lönsamhet vid skörd av skogsbränsle i klen björkgallring
The aim of the study was to compare productivity in first thinning of birch stands, when either energy- or pulpwood was harvested. The systems total profitability was also compared by including forwarding and chipping costs. A Gremo 950 HPVR harvester was used and the same driver was used under the entire study. During the pulpwood harvest a Logmax 4000b harvester head was used and a feller buncher head made by Silvatec was used during the energy wood harvest. Six study unit pairs were located in a birch dominated stand outside Ängelholm in Skåne. The stand contained 2887 trees/ha, and measured 9,4 cm at breast height diameter and 11,0 m in height. The standing volume before harvest was 131 m3/ha. The harvest of energy wood was 36.1 tons dry matter (DM) per ha. The pulpwood harvest was 32.2 m3 per ha. The harvest of energy wood was 54.8 % larger per ha than the harvest of pulpwood calculated as ton DM per ha. The time consumption per ha was for the energy wood method 7.0 E0- hour per ha, and for the pulpwood method 11.3 E0- hour per ha. This gave a productivity of 5.2 ton DM/ E0- hour or 1.4 ton DM/ E0- hour respectively. The number of damaged trees in the remaining stand was 5 % in the energy wood method and 8.7 % in the pulpwood method. There was not a significant different between the methods. The net yield, including chipping and forwarding was included was 5303 SEK per ha for the energy wood system and -518 SEK per ha for the pulpwood system.