Studies On The Tree Seedling Dynamics Of Coniferous And Broad Leaved Mixed Forests In Changbai Mountain

This paper is to understand the dynamics and effects on seedling survival in coniferous and broad leaved mixed forests in north-eastern China.1140 seedling monitoring quadrats were set at Changbai Mountain, of which DBH<lcm seedling in our quadrats were tagged, measured and identified to the species. Based on 15 censuses between 2013 and 2015, we analyzed species composition and interannual dynamics of all seedlings, especially for seedling recruitment and death. We examined the relative importance of biotic neighborhood and habitat heterogeneity on seedling survival by using generalized mixed linear model. A total of 22 tree seedlings species were identified and recorded. There had a little difference of the species composition between 2013 and 2015. We monitored 11 common seedling species each year. There were great temporal fluctuation in the seedling density, which have highest density of 11.3 seedlings m-2 and lowest density of 1.4 seedlings m-2. The local environment suitable for the adult growth was also suitable for seedling survival. On the other hand, seedling density had significant negative effect on seedling survival due to the individual competition. Particularly, we found significant negative density-dependent effects on seedling survival which was caused by conspecific adult and seedling neighbors. As expected, with the increasing of seedling survival age, the habitat heterogeneity became more important on seedling survival. We conclude that both local biotic neighborhood and habitat heterogeneity drive seedling survival in this temperate forest, and their relative importance varies with different seedling age classes and species traits.