Analysis Of Biotic Neighbors And Environmental Factors To Effect The Survival Of Tree Seedlings Under Three Large Field Plots In A Temperate Forest In Northeastern China

Seedling recruitment plays a key role in determining species composition and diversity. Exploring the patterns of seedling dynamics can therefore provide crucial insights into the mechanisms that affect seedling recruitment. The secondary Populus davidiana-Betula platyphylla forest (PBF, a young secondary forest or early successional stage)plot, the conifer and broad-leaved mixed forest (CBF, a mature secondary forest or mid-successional stage) plot and the broad-leaved-Korean pine mixed forest (BKF, an old-growth forest or late successional stage) plot represent three different successional stages in a temperate forest in northeastern China. In 2007, we established plots in the three forest and we identified, tagged, and spatially mapped each tree with diameter at breast height≥ 1 cm in every plot. Meanwhile, we also set up seedling quadrats of 1× 1m2 and censused every July. Totally, we collected datasets of adult trees and seedlings in each plot between 2012 and 2013, and examined the importance of biotic factors and environmental factors for seedling survival using a generalized mixed linear model in the three plots. The biotic factors include effect of conspecific seedling neighbors and heterospecific seedling neighbors, effect of conspecific adult neighbors and heterospecific adult neighbors, and effect of herb density and herb cover. The environmental factors include soil organic matter, available soil phosphorus, available soil potassium, available soil nitrogen, total soil nitrogen, and canopy openness. Firstly, we found that there had some differences in the different successional stages in a temperate forest:there had more significant effect factors on survival of seedlings survival in PBF than in BKF. Next, we also found the difference in effects of biotic and aboitic factors on seedlings with different ages, different seed dispersal, different species. Thirdly, Conspecific tree and seedling neighbors had a significant negative effect on survival of seedlings survival, This indicated significant negative density-dependence effects in temperate forest; Finally, had a significant effect on survival of seedlings survival. Both herb density and herb cover impacted seedling survival by modifying local habitat.