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| Titel |
Inter-annual variation of carbon uptake by a plantation oak woodland in south-eastern England |
| VerfasserIn |
M. Wilkinson, E. L. Eaton, M. S. J. Broadmeadow, J. I. L. Morison |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 12 ; Nr. 9, no. 12 (2012-12-21), S.5373-5389 |
| Datensatznummer |
250007476
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| Publikation (Nr.) |
 copernicus.org/bg-9-5373-2012.pdf |
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| Zusammenfassung |
| The carbon balance of an 80-yr-old deciduous oak plantation in the
temperate oceanic climate of the south-east of Great Britain was measured by
eddy covariance over 12 yr (1999–2010). The mean annual net ecosystem
productivity (NEP) was 486 g C m−2 yr−1 (95% CI of ±73 g C m−2 yr−1), and this was partitioned into a gross primary
productivity (GPP) of 2034 ± 145 g C m−2 yr−1, over a 165 (±6) day growing season, and an annual loss of carbon through
respiration and decomposition (ecosystem respiration, Reco) of 1548 ± 122 g C m−2 yr−1. Although the maximum variation of
NEP between years was large (333 g C m−2 yr−1), the ratio of
Reco/GPP remained relatively constant (0.76 ± 0.02 CI). Some
anomalies in the annual patterns of the carbon balance could be linked to
particular weather events, such as low summer solar radiation and low soil
moisture content (values below 30% by volume). The European-wide
heat wave and drought of 2003 did not reduce the NEP of this woodland
because of good water supply from the surface-water gley soil. The
inter-annual variation in estimated intercepted radiation only accounted for
~ 47% of the variation in GPP, although a significant
relationship (p < 0.001) was found between peak leaf area index and
annual GPP, which modified the efficiency with which incident radiation was
used in net CO2 uptake. Whilst the spring start and late autumn end
of the net CO2 uptake period varied substantially (range of 24 and 27 days respectively), annual GPP was not related to growing season length.
Severe outbreaks of defoliating moth caterpillars, mostly Tortrix viridana L. and Operophtera brumata L., caused
considerable damage to the forest canopy in 2009 and 2010, resulting in
reduced GPP in these two years. Inter-annual variation in the sensitivity of
Reco to temperature was found to be strongly related to summer soil
moisture content. The eddy covariance estimates of NEP closely matched
mensuration-based estimates, demonstrating that this forest was a
substantial sink of carbon over the 12-yr measurement period. |
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