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Titel |
Carbon dioxide fluxes over an ancient broadleaved deciduous woodland in southern England |
VerfasserIn |
M. V. Thomas, Y. Malhi, K. M. Fenn, J. B. Fisher, M. D. Morecroft, C. R. Lloyd, M. E. Taylor, D. D. McNeil |
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 ; 8, no. 6 ; Nr. 8, no. 6 (2011-06-21), S.1595-1613 |
Datensatznummer |
250005959
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Publikation (Nr.) |
copernicus.org/bg-8-1595-2011.pdf |
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Zusammenfassung |
We present results from a study of canopy-atmosphere fluxes of carbon
dioxide from 2007 to 2009 above a site in Wytham Woods, an ancient temperate
broadleaved deciduous forest in southern England. Gap-filled net ecosystem
exchange (NEE) data were partitioned into gross primary productivity (GPP)
and ecosystem respiration (Re) and analysed on daily, monthly and
annual timescales. Over the continuous 24 month study period annual GPP was
estimated to be 21.1 Mg C ha−1 yr−1 and Re to be
19.8 Mg C ha−1 yr−1; net ecosystem productivity (NEP) was 1.2 Mg C ha−1 yr−1.
These estimates were compared with independent bottom-up
estimates derived from net primary productivity (NPP) and flux chamber
measurements recorded at a plot within the flux footprint in 2008 (GPP =
26.5 ± 6.8 Mg C ha−1 yr−1, Re = 24.8 ± 6.8 Mg C ha−1 yr−1, biomass increment = ~1.7 Mg C ha−1 yr−1). Over the two years the difference in seasonal NEP was
predominantly caused by changes in ecosystem respiration, whereas GPP
remained similar for equivalent months in different years. Although solar
radiation was the largest influence on daily values of CO2 fluxes
(R2 = 0.53 for the summer months for a linear regression), variation in
Re appeared to be driven by temperature. Our findings suggest that this
ancient woodland site is currently a substantial sink for carbon, resulting
from continued growth that is probably a legacy of past management practices
abandoned over 40 years ago. Our GPP and Re values are generally higher
than other broadleaved temperate deciduous woodlands and may represent the
influence of the UK's maritime climate, or the particular species
composition of this site. The carbon sink value of Wytham Woods supports the
protection and management of temperate deciduous woodlands (including those
managed for conservation rather than silvicultural objectives) as a strategy
to mitigate atmospheric carbon dioxide increases. |
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