Dynamics of Major Tree Species in a Rare Plant Community Over 6 Years in Houhe Nature Reserve,Central China

The dynamics of common and rare tree species in a natural evergreen and deciduous broadleaved mixed forest were monitored over 6 years (2001-2007) in a 1 hm2 permanent plot in Houhe Nature Reserve,central China.The plot was dominated by 14 common tree species and 5 rare tree species.We focused on the dynamics of stems ≥5 cm DBH (diameter at 13 m above ground) of these 19 major tree species.Community ecology methods were used to measure and analyze changes in demographic and growth parameters of the major tree species.Spatial pattern of recruitment and mortality were also analyzed by point patterns analysis.Out of 998 stems,which were alive in 2001,100 died and 81 new stems developed over the 6year period.The total basal area for the 19 major tree species was initially 1956 m2/hm2,which increased to 2014 m2/hm2 by 2007.There were no obvious differences in size classes for all major tree species,and mortality was the highest for the middlesized trees.The spatial pattern of the dead stems for major tree species was random at larger scales and clumped at smaller scales.The recruited (new) stems were clumped at all scales.In addition,there was a positive interaction between the living stems and the dead stems,and a negative interaction between the living stems and the new stems at most scales.The results showed that disturbances and intra and interspecific competition were the major factors affecting the structure and dynamics of the rare plant community.The rare plant community also appeared to maintain a state of dynamic equilibrium.