上海城市近自然森林的重建动态

近自然森林作为城市植被恢复的重要模式,已在我国多地开展了实践,并衍生了新的造林模式。为评估不同近自然森林建设模式的群落恢复进程,本研究以上海城市裸地上重建的近自然森林为对象,通过长期监测两处分别应用原"宫胁法"与新"异龄复层落叶—常绿混交林"种植模式的近自然森林重建过程,从物种组成、垂直结构、生活型组成和目标恢复物种4个方面解析恢复动态。结果表明:两种造林模式恢复的近自然森林,随恢复进程其物种组成逐渐趋同,在十多年内已形成了落叶—常绿垂直混交结构;"异龄复层落叶—常绿混交林"造林模式可更好地促进常绿阔叶树种的恢复,尤其是常绿建群种红楠与小叶青冈。本研究证实了近自然森林恢复技术可以缩短亚热森林群落向演替后期发展的时间,以及新造林模式的有效性,为近自然森林技术的应用与实施提供了科学依据。

Restoration dynamics of near-to-nature forests in Shanghai

Construction of near-to-nature forests is an important way to restore vegetation in cities.This method has been used in several Chinese cities,with new afforestation models being emerged recently.To assess restoration dynamics of near-to-nature forests using different afforestation models,we carried out long-term monitoring on two near-to-nature forests in Shanghai,which were constructed by the Miyawaki model and a new deciduous-evergreen bi-cohort-andsynusia model respectively.The restoration dynamics were compared between the two models in terms of species composition,vertical structure,life form component and population size of target species.The results showed that species composition became more similar with increasing recover years between the two forests.Over a decade,both models created a kind of mixed forests with deciduous trees dominating the canopy and evergreen trees dominating the understory.The new bi-cohort-and-synusia model was better for the recovery of evergreen tree species,especially for the constructive species,Machilus thunbergii and Cyclobalanopsis myrsinifolia.This study provides empirical evidence that near-to-nature restoration method could shorten restoration time from bare ground to later succession stage in subtropical region.We recommend restoring urban vegetation by the new bi-cohort-and-synusia model to construct near-to-nature forests.