论文部分内容阅读
世界杨树研究的发展概况王世绩︵中国林科院林研所１世界各国杨树发展的趋势当前世界各国杨树发展的总趋势是：工业发达国家的杨树造林面积逐年萎缩或保持平衡；发展中国家的杨树造林面积则是保持增长的态势。意大利曾以占全国２．５％的森林面积（１５万ｈｍ２）种植杨树...
General Situation of Poplar Research in the World Wang Shiju (Lin Institute of China Forestry Academy 1 Trends of Poplar Development in Various Countries in the World The general trend of poplar development in various countries in the world is as follows: the poplar afforestation area in industrialized countries has shrunk or maintained a balance year by year; development China’s poplar area is to maintain the growth of the situation. Italy once accounted for 2.5% of the country’s forest area (150,000 hm2) planting poplars ...