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| Titel |
Effects of nitrogen fertilization on the forest floor carbon balance over the growing season in a boreal pine forest |
| VerfasserIn |
D. B. Metcalfe, B. Eisele, N. J. Hasselquist |
| 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 ; 10, no. 12 ; Nr. 10, no. 12 (2013-12-12), S.8223-8231 |
| Datensatznummer |
250085477
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| Publikation (Nr.) |
 copernicus.org/bg-10-8223-2013.pdf |
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| Zusammenfassung |
| Boreal forests play a key role in the global carbon cycle and are facing
rapid shifts in nitrogen availability with poorly understood consequences
for ecosystem function and global climate change. We quantified the effects
of increasing nitrogen availability on carbon fluxes from a relatively
understudied component of these forests – the forest floor – at three
intervals over the summer growing period in a northern Swedish Scots pine
stand. Nitrogen addition altered both the uptake and release of carbon
dioxide from the forest floor, but the magnitude and direction of this
effect depended on the time during the growing season and the amount of
nitrogen added. Specifically, nitrogen addition stimulated net forest floor
carbon uptake only in the late growing season. We find evidence for
species-specific control of forest floor carbon sink strength, as
photosynthesis per unit ground area was positively correlated only with the
abundance of the vascular plant Vaccinium myrtillus and no others. Comparison of understorey
vegetation photosynthesis and respiration from the study site indicates that
understorey vegetation photosynthate was mainly supplying respiratory
demands for much of the year. Only in the late season with nitrogen addition
did understorey vegetation appear to experience a large surplus of carbon in
excess of respiratory requirements. Further work, simultaneously comparing
all major biomass and respiratory carbon fluxes in forest floor and tree
vegetation, is required to resolve the likely impacts of environmental
changes on whole-ecosystem carbon sequestration in boreal forests. |
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