基于格网和物元模型的防护林质量评价

Quality Evaluation of Protection Forest Based on Grid and Matter Element Model

利用2006年度平通河流域ETM+卫星图片,结合该区域森林资源二类调查小班数据、林相图、1∶5万和1∶10万地形图,卫星图片解译后,将矢量文件转换成格网,选取林分结构因子、生产力因子和功能因子,采用物元分析法对每个格网进行了分级评价。结果表明:(1)平通河流域薪炭林面积占很大优势,面积为32 785.4 hm2,占总面积的42.45%;其次是水土保持林和水源涵养林,前者为18 441.86 hm2,占总面积的23.88%;后者为12 047.44 hm2,占总面积的15.60%。经济林面积较小,面积为4 217.3 hm2,仅占总面积的5.46%。(2)平通河流域防护林质量总体评价较差,以中等级所占比例最大(62.75%),其次是良好等级(21.21%);处于差等级的所占比例也占到13.96%;处于优等级的只占1.24%。

Interpreted ETM＋ in 2006,1∶50 000 and 1∶100 000 topographical map,forest type map,data of Class II forest inventory in 2007 in Pingtonghe watershed were applicated.Firstly,the satellite images was interpreted and the vector format was converted to grid format,then grade assessment of each grid was carried out by using element model on the basis of selecting stand structure factor,production capacity factor and function factor.The results showed that：（1） The area of firewood forest in this area was in the ascendant（32 785.4 hm^2,or occupying 42.45% of the total area）;it was followed by water conservation forest and soil and water conservation forest,the former occupied 23.88%（18 441.86 hm^2） and the latter accounted for 15.60%（12 047.44 hm^2）;while economic forest only occupied 5.46%（4 217.3 hm^2）.（2） On the whole,the quality of protection forest was poor： the middle grade occupied 62.75%,the next was fine grade（21.21%）,the poor grade made up 13.96%;however,the superior grade only accounted for 1.24%.