2000 Fiscal Year Final Research Report Summary
Evaluation of CO2-fixation capacity in Sugi (Cryptomeria japonica) canopy
| Project/Area Number |
10460066
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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
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
GYOKUSEN Koichiro KYUSHU UNIVERSITY, Faculty of agriculture, Associate Prof., 大学院・農学研究院, 助教授 (80205062)
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| Co-Investigator(Kenkyū-buntansha) |
SAKUTA Kotaro KYUSHU UNIVERSITY, Faculty of agriculture, Assistant Prof., 大学院・農学研究院, 助手 (10274523)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Sugi / Branch structure / Leaf distribution / Leaf nitrogen distribution / CO2-fixation |
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| Research Abstract |
To reveal the CO2-fixation capacity of Sugi (Cryptomeria japonica D.Don) canopy, (1) branch structure which determine the leaf distribution, (2) leaf nitrogen distributin in a crown which determine the leaf productivity were investiqated.
(1) branch structure
Branch density and branch distribution in an individual sugi crown were determined hereditarily, and these branch characteristics can be used as parameters of crown structure model.
The branches attached at the upper and middle parts of a crown had the space spreading function and the lower branches had the spcace filling function.
Thinning had not affected the crown shape, but leaf mass and their distribution had changed. We concluded that thinning has an effect on leaf productivity by changing leaf mass and their position.
The growth of stem and branch had decreased after pruning. The decreasing rate of branch growth was smaller than that of shoot, then the crown shape had changed to an umbrella type. This phenomena can be explained as a rearrangement of leaves for the compensation of photosynthetic organ loss.
(2) Leaf nitrogen distribution
Nitrogen content of a current year leaves decreased according to light intensity decrease, then nitrogen content of upper crown was high and that of lower crown was low. Nitrogen content of old leaves was low and constant.
The effect of growing site on leaf nitrogen content was investigated. Leaf nitrogen content in a crown was under the control of two parameters, namely, light intensity and site index. These two parameters can be used as main factors affecting leaf nitrogen content in a crown.
A model for estimating CO2-fixation of a Sugi canopy was constructed using leaf nitorogen distribution and leaf photosynthesis parameters. This model was applied to a some sugi stand and the calculation result was sufficiant for explaining the stand's data.
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