Study on Community Characteristics of Secondary Pinus yunnanensis Forest in Southeast Tibet

This study was to illustrate the distribution patterns of secondary Pinus yunnanensis forest,plant species,species important values and species diversity were analyzed based on an investigation of secondary Pinus yunnanensis forest in southeast Tibet.The results showed that the survey plots had high plant species richness,with 41species belonging to 20 families and 32genera.The species important value of Pinus yunnanensis in sunny slope was higher than on the shady slope in all altitude in our study,and increased with the altitude elevating.In shrub,the highest species important value was Berberis julianae Schneid at the altitude of 2 100mand Desmodium elegans at the altitude of 2 300,2 500min sunny slope.Berberis julianae Schneid showed highest species important value at the altitude of 2 100mand 2 300min shady slope,Lyonia ovalifoliatook the first place when the altitude was 2 500m.Pteridium aquilinumjust belowPinus yunnanensisin all experiment altitude and slope,increased first and then decreased in sunny slope,but continuously reduced in shady slope with the altitude elevating.The species richness index in shady slope was higher than in sunny slope,the maximum species richness index was at the altitude of 2 300min shady,and decreased with the altitude elevating in sunny slope.The shannon index,pielou index and simpson index in shady slope was higher than in sunny slope,and decreased with the altitude elevating.