Abstract: Sorbus pohuashanensis is an important non-timber tree species in Northeast China, but poor in natural regeneration via seed dispersal. In this paper, a field observation was made on the seed dispersal of S. pohuashanensis, its seedling emergence, and soil seed bank, aimed to study the factors affecting the natural regeneration of this tree species. There were 96.1% of naturally dispersed S. pohuashanensis seeds distributed within the range of 2 m around the stock tree, and 97.0% of the seeds in soil seed bank distributed in litter layer and 0-2 cm surface soil. The seed quantity in soil seed bank differed greatly with seasons, being the maximum ［(257.7±69.2) seeds per square meter］in early November in the year of seed dispersal, and the minimum［only (2.9±2.9) seeds per square meter］in next July. Temperature was not the limiting factor affecting the seedling emergence of S. pohuashanensis ［at 0 ℃-5 ℃, the seedling emergence percentage could reach (67.5±6.6)%］,but strongly affected the seedling emergence rate. The most proper soil moisture content for the seedling emergence was 50%, under which, the seedling emergence percentage could reach (74.7±4.2)%. When the soil moisture content was up to 60%, the seedling mortality was the lowest (32.6%±0.6%). All the results suggested that the seed dispersal pattern of S. pohuashanensis and the spatiotemporal dynamics of soil seed bank could affect the seedling emergence of the tree species, and further, affect the population natural regeneration of S. pohuashanensis via seed dispersal.

Key words: Sorbus pohuashanensis, seed dispersal, soil seed bank, seedling emergence, natural regeneration, afforestation mode, Hippophae rhamnoides,  soil microbial community,  functional gene, abundance.