古田山亚热带常绿阔叶林树皮厚度的变异特征

Variation of bark thickness among woody species in a subtropical evergreen broadleaved forest,east China

树皮是木本植物茎干最外层结构,具有保护茎干、养分储存与运输等重要作用。因此,树皮厚度是一项非常重要的功能性状,其变异不仅影响树皮的各种生态功能,还能影响群落构建与物种共存。然而,以往对树皮厚度的研究集中于火灾易发生态系统,对火灾不易发生的亚热带常绿阔叶林的研究仍较缺乏。测量了古田山国家级自然保护区亚热带常绿阔叶林内树种的树皮厚度,并检验了总树皮厚度、内树皮厚度与外树皮厚度在各分类群间以及功能群间的差异。结果发现:1)39个树种807个个体的总树皮厚度、内树皮厚度与外树皮厚度均值分别为1.90 mm、1.38 mm和0.54 mm。漆树科(Anacardiaceae)、杨梅科(Myricaceae)以及亚热带常绿阔叶林代表类群壳斗科(Fagaceae)、山茶科(Theaceae)的树皮厚度较大。短柄枹(Quercus serrata)、木荷(Schima superba)、小叶青冈(Cyclobalanopsis myrsinifolia)等树种的树皮厚度较大。2)种间、科间的各树皮厚度差异均显著。不同功能类群间,乔木类群的各树皮厚度均较灌木类群大,常绿类群的各树皮厚度均较落叶类群大(内树皮厚度除外)。本次研究结果表明,相对于火灾易发生态系统中的树皮厚度,古田山亚热带常绿阔叶林群落内的树皮厚度相对较薄,表明这些森林树种对当地湿润气候的适应性。同时,树皮厚度在各种分类水平与功能群水平间的显著变异,反映了群落内不同生态策略的共存。

Bark,the outermost structure of the stem in woody species,plays important roles in protecting stem,nutrient storage and transportation.Therefore,bark thickness is a very importantly functional trait,and its variation not only affects various ecological functions of bark,but also affects community construction and species coexistence.However,previous studies on the bark thickness focused on the fire⁃prone ecosystem.Bark thickness in fire⁃free subtropical evergreen broad⁃leaved forests has still not been investigated.In this study,we measured the bark thickness of woody species in a subtropical evergreen broad⁃leaved forest in Gutianshan National Nature Reserve(GNNR),and examined the variations of bark thickness,including total bark thickness(TBT),inner bark thickness(IBT)and outer bark thickness(OBT),at species,family and functional group levels.The results showed that:1)the TBT,IBT and OBT of 807 individuals from 39 species were 1.90 mm,1.38 mm and 0.54 mm,respectively.The family Anacardiaceae,Myricaceae and the dominant families like Fagaceae and Theaceae had larger TBT,IBT and OBT,as well as species as Quercus serrata,Schima superba,Cyclobalanopsis myrsinifolia.2)There were significant differences in TBT,IBT and OBT among species and among families,respectively.Among different functional groups,the TBT,IBT and OBT of tree species were larger than those of shrub species.The TBT and IBT of evergreen species were larger than those of the deciduous species.In this study,bark thickness in the subtropical evergreen broad⁃leaved forest community of GNNR is relatively thinner than that of the fire⁃prone ecosystem,indicating the adaptability of these species to the local humid climate.The significant variation of bark thickness reflects the coexistence of different ecological strategies within the community.