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本文根据防护林带的林学特征和气象学特征(透风系数为主),将林带划分为三类四种:一、紧密结构林带(透风系数小于0.4),二、疏透结构林带,(透风系数0.41—0.60),三、稀疏结构林带,包含:(一) 稀透结构林带(透风系数0.61—0.80),(二) 通风结构林带,(透风系数大于0.81)。本文以吉林省及内蒙古自治区东部部分地区为例,划分出:一、干旱防护林区;二、大风防护林区;三、风沙防护林区。
According to the characteristics of forestry and meteorology (the coefficient of ventilation is the main factor), the forest belts are divided into three types and four types: one is the dense belt (air permeability coefficient is less than 0.4), the other is the drenched forest belt with air permeability coefficient of 0.41 -0.60). III. Sparse structure of forest belts, including: (I) Rarity forest belt (ventilation coefficient of 0.61-0.80), (II) ventilation structure of forest belt, (ventilation coefficient greater than 0.81). Taking Jilin Province and some areas in the eastern part of Inner Mongolia Autonomous Region as an example, this paper divides out: a. Shelter shelter forest area; 2. Gale wind shelter forest area;