论文部分内容阅读
美国制定一个加强核桃林的研究计划,企图在10—15年内提高现有未成熟林的生长率和质量。为此,在南伊利诺斯大学将成立核桃林研究中心。核桃木是美国一种最珍贵的硬阔叶材,是制家具、拼花地板、鎗托等的传统优良用材,而现有资源远不能满足将来的需要。营造新核桃林需要35—40年才能见效。虽然商业部对核桃木出口作了限制。但仍不能缓和供应的紧张。市场要求在短期内增加核桃木供应量。改良现有林是见效较快的办法。一核桃木研究机构的负责人指出,在10年左右时间内将直径25厘
The United States has developed a research program to strengthen walnut forests in an attempt to increase the growth rate and quality of existing immature forests in 10-15 years. To this end, the University of Southern Illinois will set up Walnut Forest Research Center. Walnut is one of the most precious hardwood leaves in the United States. It is a traditional fine material for furniture, parquet, butt and the like, and the existing resources are far from meeting the future needs. It takes 35-40 years to create a new walnut forest to bear fruit. Although the Ministry of Commerce restrictions on the export of walnut. But still can not ease the supply of tension. Market demand to increase the supply of walnut in the short term. Improving the existing forest is a quick solution. A head of a walnut research institutes pointed out that in about 10 years the diameter will be 25%