近15年来南京城市居住区树木结构变化研究

【目的】研究城市发展和更新改造背景下树木结构和功能变化特征及机制,为城市改造中的绿化结构优化、城市绿化管理及规划提供依据。【方法】以南京中心城区8个居住小区为案例区,基于1999年和2015年每木检尺调查数据,从树种构成、形态结构与健康状态3个层面对城市更新过程中居住区树种结构及其生长质量变化动态进行研究,并探究其影响因素。【结果】女贞作为南京特色乡土树种,在两个年份的多度排名均居榜首,而三角枫、桃树、白玉兰、泡桐等本地乡土树种数量呈现大幅下降,并退出多度前20之列; 居民偏好、环境效益、市场因素是驱动居住区主要树种构成变化的主导因素,城市更新改造一定程度上影响树木数量与种类结构; 拥挤的建成环境限制了树木的生长空间,造成平均冠幅下降14.6%。【结论】树木养护管理不利和居民行为破坏是致使近年南京城市居住区树木健康状况下滑的主要原因,建议引导调整居住区的树种配比,禁止随意修剪树木,加强城市更新地块的绿化建设。

The change of trees structure in urban residential area of Nanjing City in the recent 15 years

【Objective】This study on the dynamics of urban tree structures and their affecting factors is important for urban greening and urban tree management in the process of urban renewal. 【Method】 Based on the tree survey data of the Nanjing City area respectively in 1999 and 2015, the change in tree structure and performance in the rapidly renewing residential area was studied via investigating into the species composition, morphology, and health conditions, and their affecting factors were analyzed. 【Result】The abundance of Ligustrum incidum, a native tree species, ranked the largest over the 15 years, while the abundances of Acer buergerianum, Prunus persica, Magnolia denudata, Paulownia fortunei and some other native tree species dropped drastically out of the top 20. Residents' preferences, environmental benefits, and the economical market were the dominant factors driving the changes in species composition and configuration, while urban reconstruction also influenced the changes to some extent. The limited space greatly restricted tree form development in the built environment, leading to the average crown size dropping by 14.6%.【Conclusion】 A lack of tree maintenance and residents' adverse behavior accounted for a decline in the health of residential trees in recent years. Suggestions for improvement included adjusting tree species composition, forbidding the random pruning of trees, and strengthening the greening of reconstructed land.