绿洲-荒漠过渡带防风固沙林疏透度的数字化测定及应用

Digitized Measurement of and Application to Shelterbelt Porosity of Windbreaks and Sand-fixation Forests at An Oasis-desert Ecotone

为更准确、快速的定量测定林带疏透度,运用数码相机FUJIFILM FinePix S5000和图像处理软件Photo-shop7.0相结合的方法对林带疏透度进行了数字化测定,并将其应用于新疆准噶尔盆地南缘绿洲-荒漠过渡带防风固沙林疏透度的分析。结果表明:在误差范围为0.01-0.06时,结合数码相机利用Photoshop软件对疏透度进行数字化测定能够达到较高的精度;林带疏透度与平均枝下高、平均冠高(或平均高度)和冠层面积存在极显著关系(r2=0.968,p=0.000),冠部疏透度与胸高断面积存在极显著关系(r2=0.658,p=0.000),故林业上可利用林带疏透度和冠部疏透度与其它结构因子的主导因子模型对过渡带防风固沙林的疏透度进行调整,使其对绿洲发挥更好的防护效应。

The experiment was carried out in April this year and the windbreaks and sand-fixation forests were in winter facies,when leaves and branches were not completely grown and its sheltering effects were low,so it was essential to study its porosity at this point.In order to get more rapid and accurate quantitative measurement on shelterbelt porosity,we conducted digitized measurement on porosity of windbreaks and sand-fixation forests at an oasis-desert ecotone in the south edge of the Junggar Basin and analyzed the accuracy of this method at the same time by exerting digital camera FUJIFILM FinePix S5000 and computer image disposal software Photoshop7.0.Firstly,through one-way ANOVA and standard error analysis,we elicited that using Photoshop and digital camera could realize the digitized measurement on porosity,which is exact and credible in the extent of 0.01-0.06 of standard error.In addition,we established the dominant factors model via stepwise regression between porosity and other structural factors of shelterbelts.We found that there existed significant correlation among total porosity and the area of crown and the average of crown and the average of clear bole height（r2=0.968,p=0.000）.There was also significant correlation between crown porosity and the area on breast height（r2=0.658,p=0.000）.Therefore,we aim at utilizing these models to enable us to adjust porosity of windbreaks and sand-fixation forests in order to make them exert better sheltering effects to the oasis.