Abstract:Regeneration characteristics of main woody plant seedlings in pine-oak mixed forest were conducted in Huoditang Forest in Qinling Mountains.The results showed that:(1)Forty tree species were found in the tree layer of the pine-oak mixed forest.The dominant species were Pinus tabuliformis,Quercus aliena var.acuteserrata and Pinus armandii showed important values of 35.19%,31.99% and 8.12%,respectively.The subdominant tree species were Toxicodendron vernicifluum,Quercus variabilis and Swida macrophylla exhibited the important values higher than 1%.(2)There were 87 woody plant species under the regeneration layer,34 tree species of the 87 woody species under the regeneration layer.The dominant species included Q.aliena var.acuteserrata,Rubus corchorifolius and Smilax china with the important values higher than 7%,and the shrub species offer mild advantages under the regeneration layer.The seedling and sapling densities of trees have obvious difference at different highness class under the regeneration layer,and the seedling bank was abundant with lower height class.(3)Seedling and sapling densities of Q.aliena var.acuteserrata were significantly higher than those of P.tabuliformis and P.armandii.Seedling density of Q.aliena var.acuteserrata was significantly higher than its sapling density.However,no significant difference was found in P.tabuliformis and P.armandii.(4)The diameter structure of Q.aliena var.acuteserrata population in the pine-oak mixed forest revealed a reverse J-shaped distribution from small size class to large size class.The populations of P.tabuliformis and P.armandii appeared to be normal distribution in the pine-oak mixed forest,which means that the individuals of large size class were relatively stable,but lack of saplings in the pine-oak mixed forest.The results suggest that although Q.aliena var.acuteserrata population exhibited obstacle from seedling development to sampling,the overall population regeneration did not affect.Q.aliena var.acuteserrata population will keep the reverse J-shaped regeneration pattern if no large-scale interference and will take the place of the P.tabuliformis to be the first dominant species.P.tabuliformis and P.armandii populations’ lack of saplings but existed many mother trees,this will not contribute to staying in community for a long term.