元宝山中山针阔叶混交林林窗特征及更新研究

元宝山中山针阔叶混交林以小林窗居多,林冠林窗中面积5~30m2的林窗所占面积比为39.3%,扩展林窗中面积50~100m2的林窗所占面积比达51.8%。林窗形成方式以折干和根拔倒为主,分别占形成木总数的50.0%和31.3%,冬季积雪积冰和强劲的风力是林窗形成的主要外部驱动力。林窗形成木的种类主要是包果石栎(Lithocarpus cleistocarpus)、褐叶青冈(Cyclobalanopsis stewardiana)、南方红豆杉(Taxus wallichianavar.mairei)、马蹄参(Diplopanax stachyanthus)等树种。林窗内的幼苗密度高于林冠下。乔木上层优势树种的幼苗更新情况各异,元宝山冷杉幼苗在林窗和林冠下都更新良好,南方红豆杉林窗更新较为显著,南方铁杉表现为较明显的林冠下更新。

Gap Features and Regeneration of the Mid-montane Mixed Needle Broad-leaved Forest in Yuanbao Mountain

The most of the gaps were the form of small gap in mid-montane mixed needle broad-leaved forest in Yuanbao mountain.The gaps in size of 5～30m2 occupies 39.3% in the total area in the case of the genuine gaps,while 50～100m2 occupies 51.8% in the extended gaps.Due to the snow accumulation and the strong wind in winter,the branch break and treefall were the main types of gap makers,and accounted for 50.0% and 31.3% the total number of gap makers,respectively.Species of gap makers mostly consited of Lthocarpus cleistocarpus,Cyclobalanopsis stewardiana,Taxus wallichiana var.mairei,Diplopanax stachyanthus.For the tree seedlings,the density in the gaps is much higher than in non-gap stand,and the regeneration of dominant species of up-layer varied,Abies yuanbaoshanensis was well in both,and Taxus wallichiana var.mairei dominated in gap-regeneration mode,where as in non-gap-regeneration mode.