Harvesting systems of forest biomass resources in village forests

乡村森林具有将森林资源利用为生物质能源和农业用途的很大潜力。研究了村落森林中最低生物量的采伐制度。研究了用于白兰地等森林生物质收获的微型货运机抓斗起重机收获系统。树枝运输效率是原木的13%。切屑输送效率是原木的50%。大型削片机的运行效率是小型削片机的5~20倍，油耗是小型削片机的1/3~2/3，因此，大型削片机的成本是小型削片机的1/5~2/3。森林生物量的采伐成本为5.03~26.8日元/千瓦时，林内削片系统比植物削片系统便宜。这些价值是欧洲国家的3-30倍。但有可能通过开发高效的小型切削机和压缩生物质的运输系统来缩小差异。收获所需能量低于所获得的能量，因此从能量消耗的角度来看不存在问题。最好只采摘树枝的木质部分，并将树叶留在森林中，以防止营养减少。在收获森林生物量时，最好避免采伐，并引入电缆采伐，以避免干扰森林土壤。

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.