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    陈永辉, 张晓丽, 刘会玲, 王书涵. 甘肃大野口青海云杉距离加权大小比竞争指数研究[J]. 北京林业大学学报, 2017, 39(2): 40-48. DOI: 10.13332/j.1000-1522.20160210
    引用本文: 陈永辉, 张晓丽, 刘会玲, 王书涵. 甘肃大野口青海云杉距离加权大小比竞争指数研究[J]. 北京林业大学学报, 2017, 39(2): 40-48. DOI: 10.13332/j.1000-1522.20160210
    CHEN Yong-hui, ZHANG Xiao-li, LIU Hui-ling, WANG Shu-han. Distance-weighted size ratio competition index in the forest of Picea crassifolia in Dayekou, Gansu Province of northwestern China[J]. Journal of Beijing Forestry University, 2017, 39(2): 40-48. DOI: 10.13332/j.1000-1522.20160210
    Citation: CHEN Yong-hui, ZHANG Xiao-li, LIU Hui-ling, WANG Shu-han. Distance-weighted size ratio competition index in the forest of Picea crassifolia in Dayekou, Gansu Province of northwestern China[J]. Journal of Beijing Forestry University, 2017, 39(2): 40-48. DOI: 10.13332/j.1000-1522.20160210

    甘肃大野口青海云杉距离加权大小比竞争指数研究

    Distance-weighted size ratio competition index in the forest of Picea crassifolia in Dayekou, Gansu Province of northwestern China

    • 摘要: 在研究对比距离加权的大小比竞争指数时,采用不同竞争木确定方法和参数可反映竞争压力效果差异,为其将来在林业生产实践尤其是林业遥感中的应用提供参考。本文以甘肃大野口青海云杉天然林为研究对象,以距离加权的大小比指数通用模型为基础,采用Pearson相关性和方差分离的方法,通过探究竞争对林木高径比(树高/胸径)生长的影响,对比分析了分别采用固定面积法、树冠重叠法、圆锥搜索法确定竞争木,以胸径、树高、冠幅分别为大小比参数,以固定半径、树高和、冠幅和分别为相对距离参数时,不同竞争指数反映竞争压力效果的差异。结果显示:1)竞争指数与高径比呈显著正相关(P < 0.01),并且相关性会随着下层林木从样本中的逐渐剔除而增强。2)针对研究区林分,圆锥搜索法是3种确定竞争木方法中效果相对最好的,其次为固定面积法,最差为树冠重叠法。3)除固定面积法外,选用树高和为相对距离参数的竞争指数与高径比的相关性大于选用冠幅和。4)以胸径比为大小比的竞争指数与高径比的相关性最大,其次为冠幅比,最小为树高比。5)排除与生长因子协同作用部分,以树高比为大小比的竞争指数对高径比变异的独立解释力最大(15.7%),其次为胸径比(7.3%),最小为冠幅比(3.6%)。综上表明,针对青海云杉天然林,距离加权的大小比竞争指数能够有效反映林木所受竞争压力情况,但竞争木确定方法和模型参数选用不同,其所反映的竞争效果也不同。3种竞争木的确定方法以圆锥搜索法为最佳,距离权重函数中以树高和为相对距离参数最好,而大小比参数选用树高相对更具生态学意义。

       

      Abstract: The study was conducted to compare the differences of distance-weighted size ratio indices to reflect the effect of competitive pressure when using different methods to determine the competitive tree and parameters, and provide a reference for its future application in forestry practices, especially in forestry remote sensing. In this paper, taking Picea crassifolia natural forest as an example, we used Pearson correlation and variation partitioning analysis to compare 15 kinds of competition index, which used fixed area method, crown overlap method and vertical search cone method to select competitors, respectively, and adopt DBH, tree height, crown width as size ratio parameters, respectively, and a fixed radius, the sum of tree height, and the sum of crown width as relative distance parameters, respectively. All the above was based on distance-weighted size ratio index generalized model. Results showed that: 1) there was a significant positive correlation (P < 0.01) between competition index and height-diameter ratio (height/diameter), and the correlation with the gradual exclusion of understory trees from the samples was improving. 2) For stands in the study area, the vertical search cone method was the best in three methods on choosing competitors, followed by a fixed area method and the crown overlap method was the worst. 3) Excepting fixed area method, the correlation was stronger when choosing the sum of tree height as the relative distance parameters than choosing the sum of crown width. 4) The correlation coefficient was the highest when using the diameter at breast height as size ratio parameter, followed by using the crown width and the tree height as size ratio parameter, respectively. 5) Excluding the synergies section with growth factor, the competition index adopting height ratio as the size ratio had the largest independent explanatory power (15.7%) in explaining variation of height-diameter ratio, followed by diameter ratio (7.3%), crown ratio least (3.6%). According to the analysis above, we can speculate that for the stand in the study area, distance-weighted size ratio index can effectively reflect the competitive pressure situation, but it is different when using different methods to determine the competitive tree and parameters. In three methods on choosing competitors, the vertical search cone method is the best. The relative distance parameter adopting the sum of tree height is better. Selecting tree height as the size ratio parameter will have more ecological significance.

       

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