以2000年在上海浦东新区营建的近自然森林为研究对象,通过对群落种类组成、植株密度、植株高度、胸径和土壤养分的跟踪调查,研究了近自然森林十年间的动态变化.结果表明:经过10年生长,林分长势良好,植物种类组成基本上仍以初期种植的物种为主,伴有少量自然侵入种;由于建设前期缺乏荫蔽,苦槠(Castanopsis sclerophylla)、红楠(Machilus thunbergii)等常绿阔叶树种枯死较多,枫香(Liquidambar formosana)和女贞(Ligustrum lucidum)死亡率低、生长迅速,逐渐占据群落上层后,常绿阔叶树种逐渐适应群落环境,趋于稳定生长;随着群落的发展近自然森林土壤养分较种植初期稳定上升.针对存在的问题,结合近自然森林优化模式建设的尝试,提出了"异龄复层落叶—常绿混交林"的种植模式,为城市地标性的植物群落构建提供指导与参考.
The near-natural forest was constructed in Pudong New Area of Shanghai in 2000.The study was made by tracking investigation on species composition of communities,plant density,plant height,DBH and soil nutrient.Results showed that: After ten years,forests showed a good growth.Species of plants maintained almost unchanged except for small amount of invasive species.However,due to the lack of shade,the mortality of evergreen tree species such as Castanopsis sclerophylla,Machilus thunbergii etc.was high at the first stage of construction.While Ligustrum lucidum and Liquidambar formosana showed a rapid growth and low mortality,gradually dominating the upper stratum,indicating deciduous broadleaved species gradually found their feet and showed up a more stable growth,with soil fertility rising more steadily than that in the early planting period.In response to the problems we found above,a planting model,the bi-synusia model of deciduous and evergreen trees of uneven aged,are put forward,which might play a guidance and reference role in building near-natural urban forests.