Effect of overstory on the seasonal variability of understory herbs in primary broad-leaved Korean pine forest of Changbai Mountain

In order to study the structure of herbaceous biodiversity and its effect factors in broad-leaved Korean pine forest, a total of 100 1-m2 sub-plots were established in the 1 ha site which was monthly investigated from May to September in 2009. Data on soil attributes were also investigated (soil organic matter, available nitrogen, available phosphorus, available potassium, soil, water and pH) without light environment (leaf area index (LAI), photosynthetic photon flux density (PPFD) and, canopy presence). In this paper, the relationships between different layers (tree, shrub and herbaceous), soil attributes and light environment were analyzed. The effects of tree and shrub layers, soil attributes and light environment on the structure of herbaceous diversity were also discussed. The results show that there is an obvious seasonal dynamic for the herb in broad-leaved Korean pine forest. It was dominated by Anemone amurensis (Korsh.) Kom. and Corydalis ambigua Cham. et Schltdl. in May. The highest species richness was in June, when spring ephemeral, early and late-summer plant grew at the same time. July was the growing season and had highest diversity. From August to September, summer plant became withered gradually. There is a significant positive correlation between the diversity in shrub and herb layer Density of shrub layer positively correlated with the cover of herb layer, but negatively correlated with the diversity of herbaceous layer. The effect of the tree layer on the cover and the diversity of herbaceous layer did not arrive at the significant level. The correlation analysis of the cover, diversity and soil attributes, light environment at herbaceous layer, as well as the tree and shrub layer, indicated that available potassium, PPFD, soil water was the key connection between the tree- and shrub layer. The site locates in the broad-leaved Korean pine forest belonged to the old forest which could explain why the tree layer was not related to herbaceous layer in this paper. Therefore, it could be concluded that, the influence of the tree layer on the structure of herbaceous biodiversity carried out through the direct effect on light environment, precipitation and litter.Keywords:Tree layer, shrub layer, herbaceous layer, seasonal dynamic, soil attributes, light environmentAfrican Journal of Biotechnology, Vol 13(11), 1223-123