生徒とまとめた鳥取大学「蒜山の森」での研究の成果を投稿しました。以下は要旨です。

Forest Diversity and Carbon Dioxide Absorption

Miyuki Suzuki, Seishin Girls’ High School
Sella Takei, Seishin Girls’ High School
Shigeharu Akiyama, Seishin Girls’ High School
and
Junji Sano, Faculty of Agriculture, Tottori University

abstract　The aim of the present study is to clarify the role of forests in the absorption of carbon dioxide. In order to determine forest CO2 absorption capacities, we conducted a five-year investigation of artificial and natural forests, examining tree height, diameter and age. We then analyzed this data with regards to the forest structure and diversity of tree species. We found that artificial and natural forests absorbed CO2 at rates of 140 kg/100 m2/year and 260 kg/100 m2/year, respectively. Compared to artificial forests, the natural forests we surveyed had a complex hierarchical structures containing a wide range of tree types and trees of differing heights. We hypothesized that these characteristics allow natural forests to achieve a more efficient rate of photosynthesis. Moreover, we found that red pine trees, in particular, have a high CO2 absorption rate because of their rapid growth. We concluded that natural forests have a significantly greater ability to absorb CO2 than artificial forests. A Japanese person emits approximately 2 tons of CO2 per year from household, indicating that only 7% and 13% of the annual emissions from one person can be absorbed by 100 m² of artificial and natural forests, respectively. These results suggest that not only the protection of natural forests, but also fundamental changes in our lifestyle, are necessary to stem the rise in CO2 emissions.