Species diversity of undergrowths in Huoshan Mountains of Shanxi Province

Based on the field investigation and by using the indices of diversity,richness and evenness,this paper studied the species diversity of shrub and herb layers under forest communities in Huoshan Mountains of Shanxi Province.The results showed that under most forest communities,the diversity and evenness indices of shrub layer were higher than those of herb layer,while the richness index of shrub layer was lower than that of herb layer.The species richness index was decreased in order of coniferous and broad-leaf mixed forestconiferous forestdeciduous broad-leaf forest.Coniferous and broad-leaf mixed forest had higher species diversity than the others because it possessed the common features of both coniferous and deciduous broad-leaf forests.The peak values of these three indices of both shrub and herb layers were at the intermediate elevations about 1 500 m above sea level,where the combination of moisture and heat energy were favorable to the plant growth and development and with fewer human intervention.