Sasa dwarf bamboo commonly forms dense undergrowth in Japanese forests. However, the contributions of Sasa to ecosystem functions and services in forest have not been fully understood. We examined how multiple ecosystem functions in soil, relating to carbon sequestration, soil acidity and fertility differ according to aboveground density of Sasa in forest ecosystem.

We established experimental sites in a natural cool-temperate mixed forest site in northern Hokkaido, Japan. According to the density of Sasa, three plots with five sampling spots (1m²) were established as high (H), medium (M) and low density (L) plots to measure physical, chemical and biological properties of litter layer and mineral soil (0-20cm). The H plot was located in gap area, whereas the L plot was located under the dense canopy of coniferous trees.

The litter pH in the H plot was significantly higher than the other plots. The base saturation and the ratio of base cations/aluminum were both highest in the H plot and lowest in the L plot. Microbial respiration and inorganic nitrogen pool in soil were also higher in the H plots than the L plots. Our results suggested that the decrease in soil acidity and the increase in both fertility and microbial activity were influenced by the higher supply of Sasa litter with the less coniferous litter in gap area.