2005 Fiscal Year Final Research Report Summary
Research of carbon dynamics in the tree-litter-soil systems
| Project/Area Number |
15380107
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
林学・森林工学
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| Research Institution | Kobe University |
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Principal Investigator |
KANAZAWA Yoichi Kobe University, Graduate School of Science and Technology, Professor, 自然科学研究科, 教授 (40101092)
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| Co-Investigator(Kenkyū-buntansha) |
ISHII Hiroaki Kobe University, Graduate School of Science and Technology, Assistant, 自然科学研究科, 助手 (50346251)
FUJITAKE Nobuhide Kobe University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (50243332)
SUZUKI Takeshi Kobe University, Faculty of Agriculture, Assistant, 農学部, 助手 (10321952)
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| Project Period (FY) |
2003 – 2005
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| Keywords | dead branches / CN ratio / root respiration / soil respiration / DOC / water-soluble humic substances |
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| Research Abstract |
In a 450-year-old Douglas fir stand, attached dead branch mass was estimated at 2.60 to 5.56 t and occupied ca 1/4 of total live branchwood mass. Live branchwood died attached at a rate of 0.24% yr^<-1>. Due to branchfall and fragmentation 0.37% yr^<-1> and 4.34% yr^<-1> of live- and dead- branch mass were lost respectively. Dead wood mass of 30.88t ha-1 yr-1 was supplied from the canopy to the ground.
Live branch size distribution of Japanese broadleaved trees followed power functions with a gradient of ca 2.5, and the size of fallen branches showed the same pattern as well. The ratio of fallen to attached branches was 3 to 10% in number. In a Japanese secondary broadleaved forest under warm temperate climate, aboveground dead woody mass was estimated at 9.3tC ha^<-1>, accounting for 21% of total aboveground mass. A model parameterized by temperature, water content and decay characteristics of dead wood estimated annual respiration of dead woody parts at 0.5tC ha^<-1>. Smaller size root less than 2mm diameter occupying 15% of total root mass contributed more than 60% of total root respiration.The ratio of root to total soil respiration showed large seasonal fluctuation between 18.7% and 59.8%, although its annual mean was 47%. Annual soil respiration was 9 tC in this forest.
In the same forest, water-soluble organic matter in soil was retained largely in A horizon. Carbohydrate moiety in the water-soluble humic substances decreased from litter to B horizon. Chemical and structural properties of the water-soluble humic substances changed with soil depth probably due to microbial degradation in litter and to adsorption to mineral soil in mineral horizon. Humic acids accumulated in soil accounted for 15-16% of total soil organic matter and were 7-24 times higher than water-soluble organic matter.
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