极端气候下城市绿化树种对干旱胁迫的响应研究——以江西省南昌市为例

Study on the Response of Urban Green Space Tree Species to Drought Stress in Extreme Climate—Taking Nanchang City,Jiangxi Province as an Example

随着全球气候变化及城市化进程加快,导致极端气候频发,城市生态环境质量下降。城市绿地作为城市生态功能发挥、生态服务提供的核心,其植物遭受到了极端气候的严重威胁——干旱枯亡、冰雪折损等,因而加强城市绿地对极端气候的响应研究具有必要性和迫切性。以2019年南昌市所遭受的极端干旱气候为例,对南昌市绿地受干旱胁迫树种进行分析,结果表明:(1)调查的树木中,受到干旱胁迫的影响占比较高的为树木冠幅较小和树高较矮的树木;(2)常绿树种相较于落叶树种叶片较多、不易脱落,且干旱胁迫发生在南昌较高温度的时间段,进一步加剧了蒸腾量,常绿树种对干旱胁迫的响应较为明显。在常绿树种的种植时,考虑适当增加针叶树种的比例;(3)城市绿化树木所处的空间环境影响树木对干旱胁迫的响应,狭小受限空间环境对树木的生长有所限制,树木呈不健康状态更易受干旱胁迫;(4)城市绿地会定期实施修剪、灌溉、施肥等管理措施,可以有效减少干旱胁迫对于城市绿地的影响。

With the acceleration of global climate change and urbanization,extreme weather occurs frequently.The urban ecological environment’s quality declines—urban green space as the core of urban ecological function and environmental service.The urban green space plants threatened by extreme climate,such as dry and withered,ice and snow damaged,etc.So,it is necessary and urgent to strengthen the response research of urban green space to extreme climate.This paper takes the harsh drought climate suffered by Nanchang city in 2019 as an example to analyze the tree species under drought stress in the urban green space of Nanchang city.The results show that:(1)Among the trees surveyed,the ones that are affected by drought stress are those with smaller crowns and shorter heights.(2)Compared with deciduous tree species,evergreen species have more leaves and are not easy to fall off.Drought stress occurs in the higher temperature period of Nanchang,which further intensifies the transpiration,and the response of evergreen tree species to drought stress is more prominent.In the planting of evergreen trees,the proportion of coniferous trees should appropriately increase.(3)The spatial environment of urban green trees affects the response of trees to drought stress.The setting of small confined space limits trees’growth,and trees in an unhealthy state are more vulnerable to drought stress.(4)Urban green space will be regularly pruned,irrigated,fertilized,and exerted other management measures,effectively reducing the impact of drought stress on urban green space.