上海公园绿地植物群落骨干树种根系分布特性

Root Distribution Characteristics of Backbone Tree Species of Plant Community in Shanghai’s Park Green Spaces

为实现城市公园绿地群落树种的合理配置,形成稳定健康的群落有机整体,研究以上海世博公园不同立地类型和植物群落为对象,采用Tree Radar树木雷达检测(TRU)方法,对广玉兰等7个绿化骨干树种进行根系检测,探寻不同树种、不同立地、不同群落及其交互作用下根系分布特征。结果表明:根系水平分布的特征为距离树干越远,根系密度越小;垂直方向根系分布以60~120 cm土层密度较高,而0~60 cm、120~200 cm两个土层根密度较小且相近。在树种配置上,榉树、女贞比较适宜根系空间狭小的栽植区域。在林地,主、次干道旁绿地3种立地类型中,林地土壤条件最有利于根系的生长。在乔木、乔草、乔灌草3种群落类型中,乔草、乔灌草复合群落更有利于骨干树种深层次根系形成。树种、立地和群落之间存在一定的交互作用。因此,在林地中配置乔草、乔灌草复合群落更有利于骨干树种根系延展和深根系形成,保障不同植物地下营养空间的合理分配。

For the purpose of realizing the reasonable allocation of community tree species in green spaces of urban park to form a stable and healthy tree community,the study uses Tree Radar(TRU)to detect the root system of 7 tree species,including Magnolia grandiflora,in view of different site types and plant community types in Shanghai World Expo Park,and explore the root distribution characteristics under different tree species,different sites,different communities and their interactions.The results indicate that roots’horizontal distribution is characterized with the feature of the farther away from the trunk,the smaller the root density.In the vertical direction,the root density in the soil layer of 60-120 cm is higher,while the root density in the soil layers of 0-60 cm and 120-200 cm is smaller and similar.When it comes to the configuration of tree species,Zelkova serrata and Ligustrum lucidum are found to be more suitable for planting areas with narrow root space.The soil conditions of forest land are found to be the most favorable for the root growth compared with green land beside the main and secondary roads.Among the three community types of arbor,arbor&herb and arbor&shrub&herb,the complex community of arbor&herb or arbor&shrub&herb is more conducive to the formation of the deep root system of the backbone tree species.There are also some interactions among tree species,sites and communities.Therefore,the complex community of arbor&herb or arbor&shrub&herb in woodland is more conducive to the root extension and deep root formation for backbone tree species,ensuring the rational distribution of underground nutrient space for different plants.