现在世界林业生产面临着几个大的战略转移,其一是生产基地由寒、温带向热带和亚热带转移,二是天然阔叶林向人工针叶林转移,第三是随着集约林业发展,由实生苗造林向无性系林业转移,第四,由粗放经营向集约栽培转移。这些转移的根本目的,在于缩短轮伐期,提高单位面积生产力。在完 Now the world forestry production is facing several major strategic shift, one is the production base from cold and warm to tropical and subtropical transfer, the second is the natural broad-leaved forest to artificial coniferous forest transfer, the third is with intensive forestry development, From seedling plantation to clonal forestry transfer, fourth, from extensive management to intensive cultivation transfer. The fundamental purpose of these transfers is to shorten the rotation period and increase the productivity per unit area. At the end