Effects of Ontogenetic Development on Seedling Regeneration Dynamics of Quercus Acutissima Plantation in Mount Tai

Abstract

Background: Natural regeneration is critically important for the sustainable management of artificial forests. Studies have been investigated for the effects of seedlings height distribution and ontogenetic adaptability in a 60-year-old Quercus acutissima artificial pure forest in Mount Tai. Results: The results showed that the height distribution of seedlings under the forest was pyramidal-shape from the year 2010 to 2017. In 2017, the density of seedlings under the forest was only 61.63% of that in 2010, and the number of individuals at each height class was lower than that in 2010, especially the individuals at 20-40cm height class only 32% of that in 2010. With the increase of seedling height under the forest, seedling biomass (SB), ground diameter (GD), root mass ratio (RMR), total root length (TRL), root volume (RV), root average diameter (RAD) and nonstructural carbohydrates (NSC) increased significantly, but leaf mass ratio (LMR), leaf area ratio (LAR), photosynthetic/non-photosynthetic tissue ratio (P/NP), specific root length (SRL) and specific root surface area (SRA) decreased significantly. Correlation analysis showed that SB was negatively correlated with LMR, LAR, P/NP, SRL and SRA, and positively correlated with RMR, TRL, RV, RAD and NSC. NSC was negatively correlated with LMR, LAR, P/NP, SRL and SRA. Conclusions: Therefore, with the increase of seedlings height, the increased carbon storage was helpful for the seedlings of Q. acutissima to survive under the forest for a long time, but the reduced ability of light interception, photosynthetic tissue ratio, water and nutrient absorption capacity contributed to their low survival ratio under the forest.