1987 Fiscal Year Final Research Report Summary
Effects of standing tree density of dry matter production in manmade Cryptomeria japonica forests
| Project/Area Number |
60480061
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
林学
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| Research Institution | University of Tokyo |
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Principal Investigator |
NEGISI Ken'itiroo Faculty of Agriculture, University of Tokyo, 農学部, 教授 (90011824)
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| Co-Investigator(Kenkyū-buntansha) |
TANGE Takeshi Faculty of Agriculture, University of Tokyo, 農学部, 助手 (20179922)
MATSUMOTO Yoosuke Faculty of Agriculture, University of Tokyo, 農学部, 助手 (50165916)
SHIBA Yoshihiro Faculty of Agriculture, University of Tokyo, 農学部, 助手 (20011900)
SUZUKI Makoto Faculty of Agriculture, University of Tokyo, 農学部, 助手 (40012091)
SAKURA Tsuguo Faculty of Agriculture, University of Tokyo, 農学部, 助手 (70012078)
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| Project Period (FY) |
1985 – 1987
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| Keywords | Standing tree density / Manmade Cryptomeria japonica forest / Changes in biomass with stand age / Maximum leaf biomass / Net production / CO2 exchange rate in crown / 幹の樹皮呼吸速度 |
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| Research Abstract |
Changes in abovegiound biomass with age in a young Cryptomeria japonica spacing experiment stand were estimated five times during the period before and after canopy closing, i.e.,at 14-, 15-,16-,18-,and 20-yr-old in stand ages. The stand is in Tokyo University Forest in Chiba and consists of dense (D,13,333 trees・ha^<-1>),medium (M,6,667),and sparse (S,3,333) plots. Also, measurements of net production, photosynthesis and bark respiration were made as a step toward making an estimation of gross production.
A passign higher level of leaf biomass was observed when the forest canopy was closing. The maximum leaf biomass was 44.4 t・ha^<-1> in the plot D, 42.0 in M, and 31.2 in S. After the maximum, the leaf biomass decreased rapidly with the beginning of natural thinning in D and M. The clear length of tree increased with density, and the leaf density in the crown layer became higher. But there was a limit in leaf density, nearly at 1 kg dry weight・m-3. The branch and stem biomasses increased with age by accumulation of wood except the branch in the plot D, where a passing higher level was seen as in leaf biomass.
Differences in net production estimated by adding the amounts of dead leaves and branches to the growth were not apparent among the plots at 20-yr-old in stand age. CO_2 exchange rates of entire crown in a dominant tree were compared with those in a supressed one throughout the growing season. Direct estimation of gross production will be possigle by further accumulation of data on daily surplus in CO_2 exchange in relationship to dominance of each tree in a stand. The stem respiration rates per unit bark surface area were closely orrelated with latest diameter growth.
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