Regeneration and the quantitative characteristics of trees in gaps in karst forest in Maolan Natural Reserve,Guizhou Province

Based on an investigation in gaps and non-gap stands in the karst forest of Maolan Natural Reserve,Guizhou Province,the quantitative characteristics of tree species,saplings and seedlings in gaps and non-gap stands,the regeneration responses of the shrub species to gaps were analyzed.The results showed that tree species were classified into 5 groups according to their changes of orders of importance values in gaps and non-gap stands.i.e.① strong positive regeneration response to gaps;② strong negative regeneration response to gaps;③ moderate positive regeneration response to gaps;④ moderate negative regeneration response to gaps,and ⑤ non-significant regeneration response to gaps.Recruitment of the seedlings for the different ecological groups of species in gap patches differed from that in non-gap patches were found significantly.The density of every shrub in gaps was much higher than that in non-gap stands,but average height of most shrub in gaps were shorter than those in non-gap stands.The saplings,seedlings and small diameter trees were much but large and middle diameter trees were less in gaps.Although it also had some saplings,seedlings and small diameter trees in non-gap stands,but the percentage of large and middle diameter trees were much more in non-gap stands to compare with those in gaps.The saplings and seedlings were mainly light demanding trees,middle and large diameter trees were mainly shade tolerant trees in gaps.