Harvesting systems of forest biomass resources in village forests

乡村森林在利用森林资源进行生物质能和农业利用方面具有很大的潜力。研究了村寨林分Sorest生物量的采伐制度。研究了一种用于森林生物质（如白兰地）采伐的改进的钩吊小型货轮采伐系统。树枝运输效率为原木运输效率的13%。木屑的运输效率为原木的50%。大型碎料机的碎料作业效率是小型碎料机的5-20倍，油耗为1/3-2/3，因此大型碎料机的成本为小型碎料机的1/5-2/3。森林生物量的采伐成本为5.03 ~ 26.8日元/kWh，森林采伐系统比植物采伐系统成本低。这些数值是欧洲国家的3 ~ 30倍。但是，通过开发高效的小型切碎机和压缩生物质的运输系统，有可能缩小这一差距。收获的能量远低于获得的能量，因此从能源消耗的角度来看没有问题。最好只收获树枝的木质部分，并将树叶留在森林中，以防止营养减少。在采伐森林生物量时，应避免直接采伐，并采用电缆采伐，以免破坏森林土壤。

Village forests have high potential of utilizing forest resources for biomass energy and agricultural use. The harvesting systems of Sorest biomass in village forests were investigated.1. Harvesting system of a mini-forwarder with a grapple crane improved for harvesting forest biomass such as brandies was investigated. Efficiency of transportation of branches was 13 % of that of logs. Efficiency of transportation of chips was 50 % of that of logs.2. Operational efficiency of chipping by a large sized chipper was 5-20 times as much as that of small sized ones, and 1/3-2/3 in fuel consumption, so that the cost of the large sized one was 1/5-2/3 of the small sized ones.3. Harvesting cost of forest biomass was 5.03〜26.8 yen/kWh, and the systems of chipping in the forest was cheaper than those of chipping in the plant. These values were 3-30 times as much as those in European countries. But there was a possibility to reduce the difference by developing high efficient small chippers and transportation systems of compresf5ed biomass. Energy for harvesting was mud1 lower than the obtained energy, so that there was no problem from the point of view of energy consumption.4. It was desirable to harvest only woody part of branches and to leave leaves in the forest to prevent nutrition from reducing. When harvesting forest biomass, it was desirable to avoid clear cut-ting and to introduce cable logging not to disturb forest soil.