南京江心洲长江滩地杨树纯林生态修复规划设计

Ecological Restoration of the Pure Poplar Forest on Yangtze River Floodplain Area of Nanjing Eco-Island

南京江心洲长江滩涂区域林地大部分为林相结构极为单一的杨树或柳树纯林,存在一定的生态问题,亟待改造,但由于长江滩地这一特殊的区位条件,为林地生态修复带来了一定的限制条件如洪水的季节性淹没和冲刷等。本文探讨了此区域杨树纯林的一种生态修复途径,即选择适宜的区域进行杨树疏伐和有害及入侵物种清理,在杨树纯林内部形成一定面积的林窗,为新的混交林地种植提供适宜的日照条件与发展空间。然后根据江滩常绿与落叶阔叶混交林的群落组成及结构特征,选择适宜植物物种包括枫杨(Pterocarya stenoptera)、江南桤木(Alnus trabeculosa)、苦楝(Melia azedarach)、桑树(Morus alba)、喜树(Camptotheca acuminata)等树种构成营造群落小团,在林窗内以参照“宫胁造林法”群落小团混交方式密植植物小苗,构建近自然混交林地的雏形,经过自然选择和演替过程,发展成为相对稳定的林相结构。

The existing forest on the Yangtze River floodplain area of Nanjing eco-island are pure poplar and willow forest;the biodiversity is poor which leads to low eco-value while high ecological threats. While the water level fluctuation of Yangtze River and the seasonal inundation are the challenges for the forest ecological restoration. This paper discussed an ecological restoration approach for pure poplar forest, which mainly include the thinning of the existing poplar forest and the clearance of the invasive species to create forest gaps, and the introduce of the mixed forest patches in the poplar forest. The selection of the species for the mixed forest patches were based on the careful study of the natural vegetation communities and their water tolerance capacity. The main species selected are Pterocarya stenoptera, Alnus trabeculosa, Melia azedarach, Morus alba, and Camptotheca acuminate. These species were randomly mixed in high density using young seedlings then planted into the forest gaps created. Natural succession and selection are encouraged to create a high ecological value mixed forest.