白皮松林林隙物种组成动态及更新规律

研究了白皮松林林隙物种组成和种间关系在林隙发育的各个阶段的动态变化,并对林隙内主要树种的更新反应进行了探讨。结果表明,在发育阶段为前期、中前期、中后期和后期的序列上,林隙中乔木层优势度最大的物种分别是白皮松（Pinus bungeana）、辽东栎（Quercus wutaishanica）、山桃（Prunus davidiana）和侧柏（Platy-cladus orientalis）;灌木层优势种包括白莲蒿（Artemisia gmelinii）、胡枝子（Lespedeza bicolor）、薄皮木（Lepto-dermis oblonga）和狼牙刺（Sophora viciifolia）;草本层优势种包括大披针苔草（Carex lanceolata）、糙隐子草（Cleistogenes squarrosa）、紫菀（Aster tataricus）和荩草（Arthraxon hispidus）;非林隙林分的优势种不明显。在林隙发育过程中乔木层、灌木层、草本层的平均相似性系数为0.32、0.38和0.27。可见林隙发育过程中群落各层次的相似性系数由小到大顺序为：草本〈乔木〈灌木;草本植物随着林隙环境条件的改变而出现较大的消亡和更新,显示出较大的波动性;乔木的稳定性和连续性介于灌木和草本之间。依据林隙中树种幼苗、幼树Ⅰ和幼树Ⅱ的数量差异,可将林隙更新反应分为单峰型、双峰型、差异不明显3种,并分别以白皮松、辽东栎和油松（Pinus tabu-laeformis）为代表树种。

Dynamics of Species Composition and Regeneration Rules in the Gaps of Pinus bungeana forest Gaps in Huanglong Mountain, Shaanxi Province

Species composition dynamics and correlation coefficients of species in each layer were studied and the regeneration response of the major tree species were examined among developmental stages of gaps in Pinus bungeana forest in Huanglong mountain,Shaanxi Province.Along the gap developmental series of prophase,pro-metaphase,after-metaphase,and anaphase,the dominant species in the arbor layer were Pinus bungeana,Quercus wutaishanica,Prunus davidiana,and Platycladus orientalis.The dominant species in the shrub layer were Artemisia gmelinii,Lespedeza bicolor,Leptodermis oblonga,and Sophora viciifolia,while the dominant species in the herb layer were Carex lanceolata,Cleistogenes squarrosa,Aster tataricus,and Arthraxon hispidus.In the non-gap stands,there were no dominant species.The simi-larity coefficients of trees,shrubs,and herb species with different gap stages were 0.32,0.38,and 0.27,respectively,while the composition of herb species fluctuated greatly.The regeneration responses could be classified into unimodal curve type,double-modal curve type,no significant response type 3 groups according to quantitative dynamics of the seedlings,saplingⅠand saplingⅡin the different gap stages,to Pinus bungeana,Quercus wutaishanica,and Pinus tabulaeformis as representatives.