Relationship between Biogeochemical Processes and Forest Management in Japanese Forest Ecosystems

We reviewed the research articles to understand the current findings and to suggest the future directions on relationship between biogeochemical cycling and forest practices in Japan. The studies on the effect of forest harvest on the biogeochemical cycling in forest has been mainly conducted using the manipulation experiments in forested basin, indicating that the tree cutting caused the significant nitrate leaching to stream due to the absence of nutrient uptake by trees. However, the unique processes in Japanese forest ecosystems has been also reported such as the role of nutrient uptake by understory vegetation after the tree cutting in northern Hokkaido, nitrate absorption in volcanic ash soil in northern Kanto region, and fluctuation of stream chemistry associated with basin hydrological processes during the last decades. In steeper slopes in southern Kinki region, it was suggested that the land slide after the forest practices has strong impact on the following hydrological processes and stream chemistry. The biogeochemical hot spots in the boundary of each ecosystem such as riparian buffer, nutrient spirals in stream channel, nutrient cycling in “SATOYAMA” region would be great concern for further understandings. It would be necessary to promote the studies on the parameterization in the ecosystem process model under the effect of forest practices with attention to their regional differences.