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| Titel |
Vertical profile of branch CO2 efflux in a Norway spruce tree: a case study |
| VerfasserIn |
M. Acosta, M. Pavelka |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250062719
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| Zusammenfassung |
| Despite woody-tissue CO2 effluxes having been recognized as an important component of
forest carbon budget due to the fraction of assimilates used and the dramatic increase in
woody with stand development, there is limited research to determine the CO2 efflux vertical
variability of woody-tissue components. For a better understanding and quantification of
branch woody-tissue CO2 efflux in forest ecosystems, it is necessary to identify the
environmental factors influencing it and the role of the branch distribution within the canopy.
The proper assessment of this forest component will improve the knowledge of
the ratio between ecosystem respiration and gross primary production at forest
ecosystem. In order to achieve this goal, branch CO2 efflux of Norway spruce tree was
measured in ten branches at five different whorls during the growing season 2004
(from June till October) in campaigns of 3-4 times per month at the Beskydy Mts.,
the Czech Republic, using a portable infrared gas analyzer operating as a closed
system.
Branch woody tissue temperature was measured continuously in ten minutes intervals for
each sample position during the whole experiment period. On the basis of relation between
CO2 efflux rate and woody tissue temperature a value of Q10 and normalized CO2 efflux rate
(E10 – CO2 efflux rate at 10Ë C) were calculated for each sampled position. Estimated Q10
values ranged from 2.12 to 2.89 and E10 ranged from 0.41 to 1.19 ?molCO2m-2 s-1.
Differences in branch CO2 efflux were found between orientations; East side branches
presented higher efflux rate than west side branches. The highest branch CO2 efflux rate
values were measured in August and the lowest in October, which were connected with
woody tissue temperature and ontogenetic processes during these periods. Branch
CO2 efflux was significantly and positively correlated with branch position within
canopy and woody tissue temperature. Branches from the upper whorls showed
higher respiration activity and seasonal dynamics than branches from the lower
whorls.
The results presented in this study serve primarily to demonstrate the importance of
branch location within canopy from the point of view of the CO2 efflux. CO2 efflux from
branch woody-tissue exhibited vertical differentiation among whorls that must be taken into
account when collecting, analysis and interpreting data. The determination of CO2 efflux
from individual components at ecosystem level is still needed to gain a better understanding
of the carbon budget issues. Such data are important for evaluating effect of global
climate or other possible influences on carbon cycling and sequestration in forest
ecosystems.
Acknowledgment: This work was support by the projects CZ.1.05/1.1.00/02.0073 from
the Ministry of Education, Youth and Sports and LM2010007 from the Ministry of the
Environmental of Czech Republic |
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