Quickly accurate determination method of forest land crown density based on arcview gis 支持下的林地郁闭度的快速精确测定方法
2.
The results showed that plant height , crown breadth , leaf number , leaf breadth and sporophyll number of dryopteris crassirhizoma populations were influenced by forest crown density and light condition 结果表明：林分郁闭度和光照条件显著影响粗茎鳞毛蕨种群的株高、冠幅、叶片数量、叶片宽度、孢子叶数等形态指标。
3.
Russula subnigricans hongo grows fast after shower in the later summer and early autumn when it was hot . they emerged in the forest stand in which crown density was 0 . 9 or so . soil ph was 5 . 75 , and fagaceae species dominated 每年在夏末秋初高温阵雨之后为发生盛期。发生地林间郁闭度0 . 9左右，土壤ph值5 . 75 ，其共生树种以壳斗科为主。
4.
According to the law of different forest stand can arise different forest fire , based on the existing forest distribution at the badaling forestry center , the area percentage of different forest types , forest age , crown density and slope for each sub - compartment were analyzed , and based on the different characteristics of each sub - compartment , some rational methods of fire prevention were put forward 摘要本论文基于不同的林分能引起不同的林火特性规律，针对北京八达岭林场林分状况，统计分析了各林班不同林分类型、林龄、郁闭度、坡度的面积分布百分比，根据不同林班林分特点，提出了合理的营林防火措施。
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