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从世界的造林历史看,开始是营造单纯林以代替天然的针阔混交林。当代的营林发展趋势,又日渐以营造单纯林走向混交林,其变化的主要原因是:由于营造单纯林引起了一系列不良后果,而不得不认真考虑营造混交林。 德国是世界上发展人工林最早的国家之一,他们营造纯林的教训,引起了各国林学家的注视。德国属于温带阔叶林气候地带,天然林多由橡树、山毛榉、松树、云杉等树种形成的混交林,这些林分具有很高的蓄积量和高度的稳定性。在十八世纪德国资本主义发展时期,大量砍伐了天然林,同时也营造了大面积纯
From the world’s afforestation history, the beginning is to create a simple forest instead of natural coniferous and broad-leaved forest. The trend of current forest management is to gradually create a single forest to the mixed forest. The main reason for its change is that due to a series of adverse consequences caused by the establishment of a simple forest, it has to be seriously considered to create a mixed forest. Germany is one of the earliest countries in the world to develop plantations. They have created the lessons of pure forests and have attracted the attention of forestry experts from all over the world. Germany belongs to the temperate zone of broad-leaved forest. Most of the natural forests are mixed forests of oak, beech, pine and spruce. These forests have high stock volume and high stability. In the eighteenth century German capitalist development period, a large number of natural forests cut, but also to create a large area of pure