特大冰冻干扰后常绿阔叶林林木和幼苗的短期动态

Short Term Dynamics of Trees and Seedlings of Evergreen Broadleaved Forest after a Severe Frozen Disturbance in Damingshan,Southern China

关键词:  常绿阔叶林  冰冻灾害  干扰  更新  木本植物  大明山

Key words:  evergreen broadleaved forest  ice storm damage  disturbance  regeneration  ligneous plants  Damingshan

摘要:

[目的]探讨和阐明2008年特大冰冻干扰后广西大明山常绿阔叶林林木和幼苗的短期动态变化规律。[方法]基于2009年建立的3.2 hm²固定研究样地,对特大冰冻干扰后大明山常绿阔叶林林木和幼苗进行连续4年的监测。[结果]林木和幼苗对特大冰冻干扰存在不同的响应与适应,灾后第1年,胸径 ≥ 1 cm林木的密度和物种丰富度显著增加,之后稍微减少并维持相对稳定;而幼苗则表现为第1年显著增加,之后又显著降低。不同树种对冰冻干扰后的恢复响应存在较大差别,在4年的恢复期中,共有13个科的林木幼苗从调查样方中完全消失,虽然消失的主要是稀有种,但一些群落优势科如樟科(Lauraceae)、山茶科(Theaceae)等的物种也出现不同程度的消失、新增现象。林木密度与林木物种丰富度、幼苗密度与幼苗物种丰富度、林木密度和物种丰富度与幼苗密度和丰富度存在显著正相关关系。[结论]林木的密度与丰富度在较大程度上决定着林下林木幼苗的种类、数量及动态,这是资源有效性和林木生态生物学特性共同作用的结果。

Abstract:

[Objective] The objective of this study was to investigate and reveal the short term dynamics of tree and seedlings of evergreen broadleaved forest after a severe frozen disturbance in Damingshan in Guangxi.[Methods] Tree and seedlings of evergreen broadleaved forest in the 3.2 hm² permanent plot built in 2009 had been continuously monitored for 4 years from 2009 to 2012.[Results] The response and adaptation of tree and seedlings to the severe frozen disturbance were different.Density and richness of trees with DBH ≥ 1 cm significantly increased 1 year after the disaster, then slightly decreased and relatively stabilized.While density and richness of seedlings significantly increased 1 year after the disaster and then remarkably decreased.Recovered response of different tree species to frozen disturbance was different.Seedlings of 13 families completely disappeared in the 4 years of recover.Although the disappeared species were mainly rare species, several species belonging to the dominate families, such as Lauraceae and Theaceae, disappeared or increased to some extent.There was significantly positive correlation between tree density and richness, seedlings density and richness, tree density and richness with seedlings density and richness.[Conclusion] Tree density and richness determined the species, quantity and dynamics of understory seedlings in a large extent, which was the results of resource availability and tree ecological and biological property.