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| Titel |
Soil CO2 efflux from mountainous windthrow areas: dynamics over 12 years post-disturbance |
| VerfasserIn |
M. Mayer, B. Matthews, A. Schindlbacher, K. Katzensteiner |
| 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 ; 11, no. 21 ; Nr. 11, no. 21 (2014-11-11), S.6081-6093 |
| Datensatznummer |
250117667
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| Publikation (Nr.) |
 copernicus.org/bg-11-6081-2014.pdf |
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| Zusammenfassung |
| Windthrow-driven changes in carbon (C) allocation and soil microclimate can
affect soil carbon dioxide (CO2) efflux (Fsoil) from forest
ecosystems. Although Fsoil is the dominant C flux following
stand-replacing disturbance, the effects of catastrophic windthrow on
Fsoil are still poorly understood. We measured Fsoil
at a montane mixed-forest site and at a subalpine spruce forest site from
2009 until 2012. Each site consisted of an undisturbed forest stand and two
adjacent partially cleared (stem-fraction-harvested) windthrow areas, which
differed with regard to the time since disturbance. The combination of chronosequence and
direct time-series approaches enabled us to investigate Fsoil
dynamics over 12 years post-disturbance. At both sites Fsoil
rates did not differ significantly from those of the undisturbed stands in
the initial phase after disturbance (1–6 years). In the later phase after
disturbance (9–12 years), Fsoil rates were significantly higher
than in the corresponding undisturbed stand. Soil temperature increased
significantly following windthrow (by 2.9–4.8 °C), especially in the
initial phase post-disturbance when vegetation cover was sparse. A
significant part (15–31%) of Fsoil from the windthrow areas
was attributed to the increase in soil temperature. According to our
estimates, ~500–700 g C m−2 year−1 are released via
Fsoil from south-facing forest sites in the Austrian Calcareous
Alps in the initial 6 years after windthrow. With a high browsing pressure
suppressing tree regeneration, post-disturbance net loss of ecosystem C to
the atmosphere is likely to be substantial unless forest management is
proactive in regenerating such sites. An increase in the frequency of forest
disturbance by windthrow could therefore decrease soil C stocks and feed back positively on rising atmospheric CO2 concentrations. |
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