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一、制订标准的科学依据苗木质量与产量是受育苗的环境因子、技术水平以及树种生物学特性等综合因子的影响。制定适合全国范围内主要造林树种苗木标准,由于从南到北涉及面很广,气候土壤条件相差悬殊,树种又多,各自的生物学特性差异很大,而且制订苗木标准工作在我国尚属首次,所以难度是很大的。
First, the scientific basis for the development of standards The quality and yield of nursery stock is affected by the comprehensive factors such as environmental factors, technical level and biological characteristics of seedlings. The development of standards for seedlings and seedlings suitable for major afforestation trees in the whole country has great differences in the biological characteristics due to the wide range of soil from south to north, vast differences in climate and soil conditions, , So the difficulty is great.