Forest biomass has recently been highlighted as a renewable energy source in South Korea. As the Renewable Energy Certificate weight has been revised to encourage the use of forest biomass for energy production, forest operations have focused on the development of new technologies and harvesting methods for the extraction and utilization of forest biomass. This study examined the application of a drum chipper to forest biomass and analyzed the effects of screen size (40, 50, 65, and 80 mm) on productivity, cost, and particle size distribution. When the screen size was 40 mm to 65 mm, the chipping productivity improved by up to 3.6 times, the fuel consumption decreased by up to 29.7%, and the chipping cost was reduced by up to 31.9%. The fines content tended to decrease with an increase in screen size. The size of woodchips was less than 100 mm in length and ranged from 10 to 63 mm. The 65 mm screen was the most effective (e.g., producing optimal wood chip size at an acceptable production rate) for the chipping operation. Harvesting methods and drying time are also important factors that determine the utilization efficiency of forest biomass. Therefore, further research should be focused on the effect of moisture content on chipping productivity, power required, and fine particle size in forest biomass productions.

Interest in the production of renewable energy using forest biomass is increasing in South Korea, and improved knowledge on operations logistics to lower biomass harvesting costs is needed. This study aimed to build a low-cost forest-biomass harvesting system by analyzing the costs of two integrated (cut-to-length and whole-tree) harvesting systems for logs and logging residues. Two integrated harvesting systems were carried out in the clear-cut mixed forest on a steep slope. Compared to the cut-to-length system that separately extracts logs and logging residues in a forest, the cable whole-tree harvesting system can save $8.8/green weight ton (Gwt) because it requires no additional yarding operation cost of logging residues. Moreover, a breakeven analysis shows that the required machine utilization rates that favor whole-tree harvesting systems over cut-to-length harvesting were more than 70% for cable harvesting systems. The introduction of the whole-tree harvesting system is, therefore, required to produce forest biomass at a low cost. In the future, studies on forest-biomass processing and transportation systems will be needed to provide a biomass feedstock supply cost from stump to biomass power plant.

This study was carried out to investigate the operational time and productivity of logging operation by chain saw, yarder attached on tractor, tower-yarder, mini-truck, mini-forwarder, and chipping operations by mini-chipper, large-chipper in order to develop the efficient logging operation system for utilization of forestbiomass. As a result, the average felling and bucking time using chain saw at the site 1 and 2 was observed to be 182.7 sec/cycle and 518.5 sec/cycle respectively. The average yarding time was 202.5 sec/cycle using yarder attached on tractor and 295.1 sec/cycle using tower-yarder. The average forwarding time was 2,073 sec/ cycle using mini-truck and 2,248.4 sec/cycle using mini-forwarder. The operational time of felling and bucking using chain-saw can be delayed according to the direction of fallen trees. The selection of felling direction is very important to yarding operation because the direction between width-yarding and felling are interrelated. Productivity can be improved through educating and training operators in the yarding operations. Mini-forwarder is needed to use because of higher productivity and lower cost than mini-truck. The operational productivity of felling and bucking by chain saw was 66.96 m

No abstract

No abstract