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    王嘉楠, 夏媛倩, 赵德先, 储显, 胡马, 胡隽, 刘慧. 城市森林主要树种树冠尺度及生长空间需求[J]. 北京林业大学学报, 2018, 40(3): 42-54. DOI: 10.13332/j.1000-1522.20170331
    引用本文: 王嘉楠, 夏媛倩, 赵德先, 储显, 胡马, 胡隽, 刘慧. 城市森林主要树种树冠尺度及生长空间需求[J]. 北京林业大学学报, 2018, 40(3): 42-54. DOI: 10.13332/j.1000-1522.20170331
    Wang Jianan, Xia Yuanqian, Zhao Dexian, Chu Xian, Hu Ma, Hu Juan, Liu Hui. Crown scale and growth space demands of main tree species in urban forest[J]. Journal of Beijing Forestry University, 2018, 40(3): 42-54. DOI: 10.13332/j.1000-1522.20170331
    Citation: Wang Jianan, Xia Yuanqian, Zhao Dexian, Chu Xian, Hu Ma, Hu Juan, Liu Hui. Crown scale and growth space demands of main tree species in urban forest[J]. Journal of Beijing Forestry University, 2018, 40(3): 42-54. DOI: 10.13332/j.1000-1522.20170331

    城市森林主要树种树冠尺度及生长空间需求

    Crown scale and growth space demands of main tree species in urban forest

    • 摘要:
      目的树冠的大小直接影响树木的生态价值,探明树种合理的生长空间需求对城市森林的规划建设与经营维护有重要意义。
      方法本文以合肥环城公园内优势度靠前的10个城市森林主要树种为研究对象,运用样方调查法,选取公园6个景区57块固定样地,在对冠幅、胸径及树高等数据调查的基础上,运用线性回归法、异速生长法,利用箱型图检验离群值,比较构建冠幅、树高与胸径的最优模型,并对树木最适宜生长空间大小进行预测。
      结果不同树种冠幅与胸径、树高与胸径均存在正相关关系,但对两种模型结果进行比较可以发现,除侧柏和栾树外,异速生长模型的决定系数(R2)均大于0.3,R2整体高于一元回归模型;均方根误差(RMSE)分布范围在0.2~0.3之间,整体上小于一元回归;F值除雪松外,均高于一元回归F值。综合比较结果表明,异速生长模型拟合度优于一元回归模型;不是所有树种的冠幅、树高都与胸径高度正相关,在10个树种的研究中,银杏、女贞和椤木石楠的冠幅-胸径模型的拟合度较高,R2分别为0.793、0.757和0.665;银杏、栾树和雪松的树高-胸径模型拟合度较好,R2分别为0.772、0.579和0.547;栾树、侧柏的冠幅-胸径模型相关性较低,R2分别为0.096和0.188;构树、刺槐和桂花的树高-胸径拟合度较差,R2分别为0.065、0.010和0.112;选择分位数回归对异速生长规律进行研究,构建10种树木的异速生长模型并在95%分位数回归下进行讨论,以树木平均胸径15cm为例,预测估算出当胸径为15cm时10种树木在适宜的生长空间中的冠幅和树高大小。
      结论本文构建的最优模型的参数估计值均显著,说明冠幅、树高变量对合肥环城公园内树木胸径的变化有明显影响,其中冠幅-胸径模型拟合精度略高于树高-胸径模型的拟合精度。

       

      Abstract:
      ObjectiveThe size of canopy directly affected the ecological value of the trees, and exploring the reasonable demand for the growth of the trees was of great significance to the construction and management of urban forests. In this study, the main 10 dominated tree species in the Ring Park around Hefei City, eastern China were taken as research objects.
      MethodUsing the sample surveyed method, 57 fixed samples of 6 scenic areas in the park were selected as sampling site. On the basis of investigation of crown width, DBH and tree height, the linear regression method and allometric method were used to construct the optimal regression model of crown width, tree height with DBH. After using the box diagram to check the outliers, the best suitable spatial scale for the tree growth was predicted.
      Result(1) There were positive correlations between crown width and DBH, tree height and DBH, but by comparing the results of two models, it could be found that the values of R2 of allometric models were higher than the simple regression models, and the value was more than 0.3 except Koelreuteria paniculata and Platycladus orientalis. While the distribution ranges of RMSE of allometric models were generally less than the simple regression, and the values ranged between 0.2-0.3. In addition to Cedrus deodara, the F values of allometric models were higher than that of simple regression. Synthetically, the fitting rate of the allometric model was better than that of the simple regression model. (2) Not all the crown width and tree height of 10 tree species were highly correlated with the height of DBH. The crown width-DBH models of Ginkgo biloba, Ligustrum lucidum and Photinia davidsoniae were fitted well, with 0.793, 0.757 and 0.665 were R2 values, respectively. The tree height-DBH models of Ginkgo biloba, Koelreuteria paniculata and Cedrus deodara were fit, and the R2 values were 0.772, 0.579 and 0.547. While the correlation between crown width and DBH models of Koelreuteria paniculata and Platycladus orientalis was lower, the R2 values were 0.096 and 0.188. The tree height-DBH models of Robinia pseudoacacia, Broussonetia papyrifera and Osmanthus fragrans were poor, and the R2 values were 0.065, 0.010 and 0.112. (3) The regression of quantiles was selected to study allometry. The allometric models of 10 species of trees were constructed and the analyses were discussed under the regression of 95 % quantile. Taking the average DBH of 15cm as an example, it was estimated that when the DBH was 15cm, the crown width and tree height of the 10 tree species in the appropriate growth space were estimated.
      ConclusionThe estimated values of the optimal model constructed in this paper were significant, which indicated that the crown width and tree height variables had a significant effect on the change of DBH in the Ring Park around Hefei City. The fitting accuracy of crown width-DBH model was slightly higher than that of tree height-DBH model.

       

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