Abstract:To study the impacts of different forest canopy conditions of Taiwania flousiana forest on Sinarundinaria basihursuta population,and reveal whether they affect the ramet structures and to estimate the effect sizes,we systematically conducted comparative survey about ramet population structures(including height,basal diameter,biomass allocation,leaf area and number of ramets) and age structure of S.basihursuta in:forest understory(FU,S=50.7 m2),moderate gap(MG,S=160.4 m2),large gap(LG,S=406.7 m2) and forest edge wildness(FEW,S=1 086.3 m2) of T.flousiana forest in Leigong Mountain Nature Reserve of Guizhou Province,Southwestern China.The main results showed that:(1)The height(h),basal diameter (bd) and biomass of S.basihursuta ramet population significantly increased in the sequence of FU→MG→LG.(2)The modular biomass percentage of S.basihursuta ramets varied with different canopy conditions.Branch and leaf biomass percentage decreased in the order of FU→MG→LG→FEW.The biomass percentage of rhizome and roots in the FEW were both significantly higher than those in the other three canopy environments.(3)The ramet specific leaf weight significantly increased in the sequence of FU→MG→LG→FEW.In the MG,the individual leaf biomass was the heaviest and the individual leaf area the largest,followed by those in the FEW,both were respectively different from those in the FU or LG;Leaf number per ramet in the LG was the biggest and was significantly different from the other three canopy conditions;(4)The ramet population mortality was the lowest in the FU,while there was no significant difference in the average population age.All the results indicated that it was not ramet age,but the morphological changes and biomass distribution that exhibited the response of the ramet population of S.basihursuta to changed canopy conditions.