How much carbon does runoff through stream compared with assimilated carbon by forests

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H02238
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 40010:Forest science-related
• Research Institution: University of Miyazaki
• Principal Investigator: Takagi Masahiro 宮崎大学, 農学部, 教授 (70315357)
• Co-Investigator(Kenkyū-buntansha): 篠原 慶規 宮崎大学, 農学部, 准教授 (10615446) ; 松本 一穂 岩手大学, 農学部, 准教授 (20528707)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 炭素収支 / 森林

Outline of Final Research Achievements

The object of this study was to measure quantity of assimilation and flowout of carbon of the forest at the same time and was to clarify the carbon budget of forest ecosystem exactly. The assimilation was measured using eddy covariance system. The flowout thorough river was estimatede by flowrate and turbidity of river water. The study site was small catchment of 50 ha with evergreen broadleaved forest in the Miyazaki University forest. As a result, the quantity of carbon assimilation became 1.5t ha-1 y-1. The carbon flowout was not able to estimated due to malfunction of the instrument. Therefore, using a value (0.37t ha-1 y-1) measured in another small basin in the past, the ratio of flowout to assimilation was calculated as 25%.

Free Research Field

森林生態学

Academic Significance and Societal Importance of the Research Achievements

森林が大気から炭素を吸収していることはよく知られている。その一方で，森林から無視できない量の炭素が河川を経由して流出していることが近年明らかになりつつある。地球全体の推定では陸上植生による吸収量の約６割が河川に流出するとされているが，流域単位の炭素収支の気候帯や国家レベルでの違いについては未解明である。本研究では日本国内で初めて森林の炭素吸収量に対する流出量を同一の試験地で測定し，その割合は小さいものとは言えない程度であることを明らかにした。