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现以苏联、美国、日本等国为例,概述一下当前防护林的营造水平和发展趋势。 一、防护林的发展水平 苏联、美国、日本等国都很重视防护林的建设,收到的效益也是非常显著的。到1982年苏联拥有人工防护林500多万公顷,防护林在森林中的比重由1956年的3％提高到1982年的20％。美国每年营造防护林1万公顷左右,到目前共造防护林近70万公顷。日本的防护林面积已达800多万公顷,占森林总面积的比重已由1953年的10％提高到现在的32％。
Now take the Soviet Union, the United States, Japan and other countries as an example to outline the current level of shelterbelt and the development trend. First, the development level of shelterbelts The United States, Japan and other countries attach great importance to the construction of shelterbelt, the benefits received are also very significant. By 1982, the Soviet Union had over 5 million hectares of artificial shelter belts, and the proportion of shelterbelts in forests increased from 3% in 1956 to 20% in 1982. The United States annually creates 10,000 hectares of shelterbelts and, to date, has created nearly 700,000 hectares of shelterbelts. Japan has more than 8 million hectares of shelterbelts, accounting for 32% of the total forest area, up from 10% in 1953.