Understory Species Diversity And Biomass Of Natural Broad-leaved Korean Pine Forest

In this paper, based on the data of field investigation in the natural broad-leaved Korean pine forest, using the Gleason richness index, Shannon diversity index, Simpson diversity index and Piolou evenness index five indicators, we studied the understory shrubs and herbs community and species diversity, and studied the understory biomass by the means of establishing biomass model about understory main shrubs (important value ranking top 10 species) and herb layer. Finally, the effect of ecological factors (topographic factors and soil factors) on understory species diversity and biomass were studied. The main conclusions are as follows:(1) There are 110 species at the understory shrubs layer and herbs layer, belonging to 41families and 96 genuses. Among them, the species of herb layer belonging to 34 families,80 genuses and 91 species,82.7% of the total numbers. The diversity indexes (Shannon diversity and Simpson diversity index) and ecological dominance at the herbs layer is higher than that at the shrubs layer, but the evenness index characterized by the shrubs above the herbs layer. Beside. As the months changed (from May to September), diversity of the herbaceous species changed peaking in June and July. But the ecological dominance index increased month by month. Herb species distribution was most uniform in July and most prominent of the dominant species in September.(2) Power function and cubic polynomial regression equation were the best biomass estimating models of shrub species. And, the composite factors such as canopy projection area, trunk volume and ground-diameter with height content of product, were the independent variable parameters of the best model. There are different biomass estimating models of each organ, and a higher accuracy. Beside, The best hybrid biomass model of shubs layer is Wt=0.012(Vc)3-0.057(Vc)2+0.189(Vc)+0.008 (R2=0.879). The optimal hybrid biomass model of herb layer is power function, based on number of the independent variable parameters. The equation for W= 1.522 (Sw) 0.882 (R2=0.624). The established models for predicting the biomass can be more accurately estimate undergrowth biomass, for future understory shrub biomass estimates the region to provide important reference.(3) At Natural broad-leaved Korean pine forests, shrub biomass increases with the diversity index, decreases with the increase of the dominance index. Howrver, herbaceous biomass has no significant correlation with diversity index, extremely significant negative correlation (p< 0.01) with evenness index, and significantly positive correlation (p< 0.05) with the species numbers.(4) The influence of ecological factors on understory pants was studied by RDA analysis. The influence of topography and soil factors on herbaceous is higher than that on the shrubs layer plant. The RDA sequence diagram shows the herb richness index(G), diversity index(D,H) were significantly related to soil total potassium content and pH value (p<0.01), and significantly negative correlation with the average elevation and slope in the topography factors (p<0.01) Shrub biomass and soil total potassium were significantly negative correlation (p<0.01), and significant positively related with slope, the concave and convex degree(p<0.01). Simpson and Shannon diversity of shrub layer and soil total phosphorus content was significantly negative correlation (p<0.01).The part of topography factors and soil factors failed to explain may be related to such factors as the stand spatial structure, it needs to be studied further.