论文部分内容阅读
目前,全世界可供生产木材的森林面积约有37.8亿公顷,每年的木材生产量达20.8亿立米。随着各国工业的发展和人口的不断增加,对木材的需要量也迅速增长。据统计,1967～1975年从20.5亿立米增到24亿立米,预计本世纪末将增加到40亿立米。这样,现有的森林资源难以满足日益增长的需要,木材的供需矛盾日趋尖锐。鉴于上述情况,大力发展阔叶速生用材林,越来越被世界各国所重视。杨树作为一个重要的速生树种,在许多适宜栽培的国家正在迅速发展。
At present, there are about 3.78 billion hectares of forest available for timber production in the world and annual timber production of 2.08 billion cubic meters. With the development of industries and population in various countries, the demand for timber has also rapidly increased. According to statistics, from 19.05 to 20.5 billion cubic meters in 1967 to 24 billion cubic meters, it is expected to increase to 4 billion cubic meters by the end of this century. In this way, the existing forest resources can hardly meet the increasing needs and the contradiction between supply and demand of timber is becoming increasingly acute. In view of the above, vigorously develop broad-leaved timber forest, more and more countries in the world attention. Poplar, as an important fast-growing species, is rapidly growing in many cultivated countries.