CARBON BALANCE AND BUDGET IN MID-TEMPERATE FOREST UNDER GLOBAL WARMING

Research Project

Project/Area Number	09480117
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Research Field	Environmental dynamic analysis
Research Institution	Hiroshima University
Principal Investigator	NAKANE Kaneyuki Hiroshima University, Faculty of Integrated Arts and Science, Professor, 総合科学部, 教授 (00116633)
Co-Investigator(Kenkyū-buntansha)	TSUCHIYA Akio Hiroshima University, Faculty of Integrated Arts and Science, Assistant, 総合科学部, 助手 (00263632)
Project Period (FY)	1997 – 1999
Project Status	Completed (Fiscal Year 1999)
Budget Amount *help	¥10,800,000 (Direct Cost: ¥10,800,000) Fiscal Year 1999: ¥2,200,000 (Direct Cost: ¥2,200,000) Fiscal Year 1998: ¥2,400,000 (Direct Cost: ¥2,400,000) Fiscal Year 1997: ¥6,200,000 (Direct Cost: ¥6,200,000)
Keywords	Global warming / Mid-temperate forest / Carbon balance / Vegetation dynamics / Photosynthesis / Decomposition
Research Abstract	The plots (25m 25m) were set up in three deciduous oak forest stands developed on the different climate zones from cool temperate (Yoshiwa) to warm temperate (Takehara) via mid temperate (Miyoshi) in the Chugoku district on June, 1996. The floristic composition, the structure of vegetation, litterfall rate, soil respiration rate and soil environmental condition were measured periodically in each plot through the year. The occupation of Quercus serrata in basal area and biomass decreased, but that of Q. variabilis increased from Yoshiwa to Takehara stands. The seedling of Q. serrata and Q. variabilis were very scarce in three plots. It suggests that Yoshiwa stand will change to small evergreen oak forest composed of Ilex pedunclosa and Pieris japonica under no human disturbance, where the material cycling rate becomes smaller than in Miyoshi or Takehara stands at present, under global warming. The annual gross (GPP), net primary production (NPP) and respiration (R), were calculated at 18.0, 4.6 and 13.4 tC/ha・yr, respectively, based on the relation between NPA (carbon assimilation rate) and PAR (photosynthesis available radiation) using the data of leaf area density and PAR, and litterfall, soil respiration, biomass increment rates observed through the year at Quercus serrata forest stand in the Yoshiwa in 1998 1999. When the global warming progresses according to IPCC Senario(1994), it predicts that NPP increases more than at present, but more decomposition rate increases under global warming, and if the vegetation changes to small evergreen oak forest as mentioned above, the carbon balance in the concerned forest will drastically change from pulas (CO2 sink) to minus(CO2 source).