近十多年来,木材采伐量的增长速度,因森林资源等条件所限,大大落后于木材需要量的增长速度。木材供需矛盾问题已经引起很多国家的重视,特别是一些少林缺材国家更感到这一问题的尖锐性。另外,水土流失、河床淤塞、水源涵养以及大气污染等问题越来越严重。因此,世界各国都很重视营林工作,大力发展速生用材林,营造防护 In the past decade or so, the growth rate of timber harvesting has lagged behind the growth of timber demand because of limited forest resources and other conditions. The contradiction between supply and demand of timber has drawn great attention from many countries. In particular, some shaolin countries are even more acute about this issue. In addition, soil erosion, riverbed silting, water conservation and air pollution have become more and more serious. Therefore, all countries in the world attach great importance to the work of forest management, vigorously develop the fast-growing timber forest and create protection