上海14种园林树种根系结构与锚固力的相关性研究

Relationship Between Root Architecture and Anchorage Force of 14 Landscape Tree Species in Shanghai

摘要:

全球气候变化引发的灾害性风暴潮和台风事件发生频度和成灾强度有不断上升的趋势，这对城市园林树木的抗风性提出了更高的要求，增强根系锚固力是提升树种抗风的重要环节。研究筛选了14种上海园林树种开展静态拉力荷载实验，比较不同树种锚固力差异，结合“完全挖掘法”采集的14种树种根系结构数据，运用相关分析和多元逐步回归分析探究了根系结构与锚固力的定量关系。实验结果为：14种树种根系锚固力排序为：细叶青冈>水紫树>三角枫>天竺桂>北美枫香>枫香>日本黄栌>豆梨>女贞>榉树>纳塔栎>乌桕>南京椴>东方杉；相关性分析筛选出11项与根系锚固力显著相关的指标，且均为正相关关系，P值由大到小依次是：直径1 500 mm范围内树根平面投影面积占比R₁₅₀₀、直径1 000 mm范围内树根平面投影面积占比R_{1 000}、直径500 mm范围内树根平面投影面积占比R₅₀₀、树根质量M_r、主要水平根数目N_h、主要斜出根数目N_o、根幅S_r、水平根垂直投影面积占比R_h、斜出根根垂直投影面积占比R_o、主要垂下根数目N_d、地径D_g；发现描述根系水平向特征的指标对根系锚固力的影响大于描述根系纵向生长的指标；多元逐步回归分析得到M_r、N_h和R₅₀₀与F_max的回归模型为：F_max=-3.620+0.699M_r+0.589N_h+0.356R₅₀₀。该研究得到了树木根系锚固力排序，发现根系的水平投影指标与根重对锚固力影响显著，研究结果为丰富华东地区园林树种抗风性评价数据库、优化抗风性园林树木的选择与管理养护提供了理论支持。

Abstract:

The frequency and intensity of disastrous storm surges and typhoon events due to global climate change are increasing， leading to heightened requirements for the wind resistance of urban landscape trees. Enhancing the root anchoring force is an important way to improve the wind resistance of tree species.Fourteen tree species in Shanghai were selected to conduct a static tension test， and the anchoring force of different tree species was compared in this paper. Based on the root distribution data of 14 tree species collected by the “complete excavation method”， the correlation analysis and nonlinear regression analysis were performed to explore the correlation between root architecture and anchoring force. The preliminary results indicate that the sequence of the anchoring forces of the 14 root systems is as follows： Cyclobalanopsis gracilis > Nyssa aquatic > Acer buergerianum > Acer buergerianum > Cinnamomum japonicum > Liquidambar styraciflua > Liquidambar formosana > Cotinus coggygria >Pyrus calleryana > Ligustrum lucidum > Zelkova serrate > Quercus nuttallii > Triadica sebifera > Tilia miqueliana > Taxodiomera peizhongii； The correlation analysis screened out 11 indexes significantly correlated with root anchorage force， all of which were positively correlated. The P values of the 11 indexes are in a descending order of R₁₅₀₀，R₁₀₀₀，R₅₀₀，M_r，N_h，N_o，S_r，R_h，R_o，N_d，and D_g. It is found that indexes describing the horizontal characteristics of roots have a greater influence on the anchorage force of roots than indexes describing the vertical growth of roots. The multiple linear regression model of M_r， N_h， R_500， and F_max is obtained by multiple stepwise regression analysis F_max=－3.620+0.699M_r+0.589N_h+0.356R₅₀₀. In conclusion， this study obtained the anchoring force ranking of tree roots and found that the horizontal projection index of roots and root weight had significant effects on the anchoring force. The results enriched the wind-resistant evaluation database of landscape tree species in East China and provided theoretical support for the selection， management， and maintenance of wind-resistant landscape trees.