CO<sup>2</sup> uptake of a mature <i>Acacia mangium</i> plantation estimated from sap flow measurements and stable carbon isotope discrimination
A simple, nondestructive method for the estimation of canopy CO<sub>2</sub> uptake is important for understanding the CO<sub>2</sub> exchange between forest and atmosphere. Canopy CO<sub>2</sub> uptake (<i>F</i><sub>CO<sub>2</sub><...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2014-03-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/11/1393/2014/bg-11-1393-2014.pdf |
| _version_ | 1819162132369899520 |
|---|---|
| author | H. Wang P. Zhao L. L. Zou H. R. McCarthy X. P. Zeng G. Y. Ni X. Q. Rao |
| author_facet | H. Wang P. Zhao L. L. Zou H. R. McCarthy X. P. Zeng G. Y. Ni X. Q. Rao |
| author_sort | H. Wang |
| collection | DOAJ |
| description | A simple, nondestructive method for the estimation of canopy CO<sub>2</sub> uptake
is important for understanding the CO<sub>2</sub> exchange between forest and
atmosphere. Canopy CO<sub>2</sub> uptake (<i>F</i><sub>CO<sub>2</sub></sub>) of a subtropical
mature \textit{A. mangium} plantation was estimated by combining sap flow
measurements and stable carbon isotope discrimination (Δ) in Southern
China from 2004 to 2007. The mechanistic relationship linking
<i>F</i><sub>CO<sub>2</sub></sub>, Δ in leaf sap, and sap flow-based canopy stomatal
conductance (<i>G</i><sub>s</sub>) was applied in our study. No significant
seasonal variations were observed in Δ or in the ratio of the
intercellular and ambient CO<sub>2</sub> concentrations
(<i>C</i><sub>i</sub>/<i>C</i><sub>a</sub>), although diurnal
<i>C</i><sub>i</sub>/<i>C</i><sub>a</sub> varied between sunlit and shaded leaves. A
sensitivity analysis showed that estimates of <i>F</i><sub>CO<sub>2</sub></sub> were more
sensitive to dynamics in <i>G</i><sub>s</sub> than in <i>C</i><sub>a</sub> and
Δ. By using seasonally and canopy averaged
<i>C</i><sub>i</sub>/<i>C</i><sub>a</sub> values, we obtained an acceptable estimate of
<i>F</i><sub>CO<sub>2</sub></sub> compared to other estimates. <i>F</i><sub>CO<sub>2</sub></sub> exhibited
similar diurnal variation to that of <i>G</i><sub>s</sub>. Large seasonal
variation in <i>F</i><sub>CO<sub>2</sub></sub> was attributed to the responsiveness of
<i>G</i><sub>s</sub> to vapor pressure deficit, photosynthetically active
radiation, and soil moisture deficit. Our estimate of <i>F</i><sub>CO<sub>2</sub></sub> for a
mature <i>A. mangium</i> plantation
(2.13 ± 0.40 gC m<sup>−2</sup> d<sup>−1</sup>) approached the lower range of
values for subtropical mixed forests, probably due to lower mean canopy
stomatal conductance, higher <i>C</i><sub>i</sub>/<i>C</i><sub>a</sub>, and greater
tree height than other measured forests. Our estimate was also lower than
values determined by satellite-based modeling or carbon allocation studies,
suggesting the necessity of stand level flux data for verification.
Qualitatively, the sap flux/stable isotope results compared well with gas
exchange results. Differences in results between the two approaches likely
reflected variability due to leaf position and age, which should be reduced
for the combined sap flux and isotope technique, as it uses canopy average
values of <i>G</i><sub>s</sub> and <i>C</i><sub>i</sub>/<i>C</i><sub>a</sub>. |
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| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-22T17:23:23Z |
| publishDate | 2014-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-b0e9ed02d77b482b98dcfc4f0013aae82022-12-21T18:18:47ZengCopernicus PublicationsBiogeosciences1726-41701726-41892014-03-011151393141110.5194/bg-11-1393-2014CO<sup>2</sup> uptake of a mature <i>Acacia mangium</i> plantation estimated from sap flow measurements and stable carbon isotope discriminationH. Wang0P. Zhao1L. L. Zou2H. R. McCarthy3X. P. Zeng4G. Y. Ni5X. Q. Rao6Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100093, PR ChinaKey laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR ChinaKey laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR ChinaDepartment of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USAKey laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR ChinaKey laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR ChinaKey laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR ChinaA simple, nondestructive method for the estimation of canopy CO<sub>2</sub> uptake is important for understanding the CO<sub>2</sub> exchange between forest and atmosphere. Canopy CO<sub>2</sub> uptake (<i>F</i><sub>CO<sub>2</sub></sub>) of a subtropical mature \textit{A. mangium} plantation was estimated by combining sap flow measurements and stable carbon isotope discrimination (Δ) in Southern China from 2004 to 2007. The mechanistic relationship linking <i>F</i><sub>CO<sub>2</sub></sub>, Δ in leaf sap, and sap flow-based canopy stomatal conductance (<i>G</i><sub>s</sub>) was applied in our study. No significant seasonal variations were observed in Δ or in the ratio of the intercellular and ambient CO<sub>2</sub> concentrations (<i>C</i><sub>i</sub>/<i>C</i><sub>a</sub>), although diurnal <i>C</i><sub>i</sub>/<i>C</i><sub>a</sub> varied between sunlit and shaded leaves. A sensitivity analysis showed that estimates of <i>F</i><sub>CO<sub>2</sub></sub> were more sensitive to dynamics in <i>G</i><sub>s</sub> than in <i>C</i><sub>a</sub> and Δ. By using seasonally and canopy averaged <i>C</i><sub>i</sub>/<i>C</i><sub>a</sub> values, we obtained an acceptable estimate of <i>F</i><sub>CO<sub>2</sub></sub> compared to other estimates. <i>F</i><sub>CO<sub>2</sub></sub> exhibited similar diurnal variation to that of <i>G</i><sub>s</sub>. Large seasonal variation in <i>F</i><sub>CO<sub>2</sub></sub> was attributed to the responsiveness of <i>G</i><sub>s</sub> to vapor pressure deficit, photosynthetically active radiation, and soil moisture deficit. Our estimate of <i>F</i><sub>CO<sub>2</sub></sub> for a mature <i>A. mangium</i> plantation (2.13 ± 0.40 gC m<sup>−2</sup> d<sup>−1</sup>) approached the lower range of values for subtropical mixed forests, probably due to lower mean canopy stomatal conductance, higher <i>C</i><sub>i</sub>/<i>C</i><sub>a</sub>, and greater tree height than other measured forests. Our estimate was also lower than values determined by satellite-based modeling or carbon allocation studies, suggesting the necessity of stand level flux data for verification. Qualitatively, the sap flux/stable isotope results compared well with gas exchange results. Differences in results between the two approaches likely reflected variability due to leaf position and age, which should be reduced for the combined sap flux and isotope technique, as it uses canopy average values of <i>G</i><sub>s</sub> and <i>C</i><sub>i</sub>/<i>C</i><sub>a</sub>.http://www.biogeosciences.net/11/1393/2014/bg-11-1393-2014.pdf |
| spellingShingle | H. Wang P. Zhao L. L. Zou H. R. McCarthy X. P. Zeng G. Y. Ni X. Q. Rao CO<sup>2</sup> uptake of a mature <i>Acacia mangium</i> plantation estimated from sap flow measurements and stable carbon isotope discrimination Biogeosciences |
| title | CO<sup>2</sup> uptake of a mature <i>Acacia mangium</i> plantation estimated from sap flow measurements and stable carbon isotope discrimination |
| title_full | CO<sup>2</sup> uptake of a mature <i>Acacia mangium</i> plantation estimated from sap flow measurements and stable carbon isotope discrimination |
| title_fullStr | CO<sup>2</sup> uptake of a mature <i>Acacia mangium</i> plantation estimated from sap flow measurements and stable carbon isotope discrimination |
| title_full_unstemmed | CO<sup>2</sup> uptake of a mature <i>Acacia mangium</i> plantation estimated from sap flow measurements and stable carbon isotope discrimination |
| title_short | CO<sup>2</sup> uptake of a mature <i>Acacia mangium</i> plantation estimated from sap flow measurements and stable carbon isotope discrimination |
| title_sort | co sup 2 sup uptake of a mature i acacia mangium i plantation estimated from sap flow measurements and stable carbon isotope discrimination |
| url | http://www.biogeosciences.net/11/1393/2014/bg-11-1393-2014.pdf |
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