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| Titel |
Simulating boreal forest carbon dynamics after stand-replacing fire disturbance: insights from a global process-based vegetation model |
| VerfasserIn |
C. Yue, P. Ciais, S. Luyssaert, P. Cadule, J. Harden, J. Randerson, V. Bellassen, T. Wang, S. L. Piao, B. Poulter, N. Viovy |
| 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 (2013-12-13), S.8233-8252 |
| Datensatznummer |
250085478
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| Publikation (Nr.) |
 copernicus.org/bg-10-8233-2013.pdf |
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| Zusammenfassung |
| Stand-replacing fires are the dominant fire type in North American boreal
forests. They leave a historical legacy of a mosaic landscape of different
aged forest cohorts. This forest age dynamics must be included in vegetation
models to accurately quantify the role of fire in the historical and current
regional forest carbon balance. The present study adapted the global
process-based vegetation model ORCHIDEE to simulate the CO2 emissions
from boreal forest fire and the subsequent recovery after a stand-replacing
fire; the model represents postfire new cohort establishment, forest stand
structure and the self-thinning process. Simulation results are evaluated
against observations of three clusters of postfire forest chronosequences in
Canada and Alaska. The variables evaluated include: fire carbon emissions,
CO2 fluxes (gross primary production, total ecosystem respiration and
net ecosystem exchange), leaf area index, and biometric measurements
(aboveground biomass carbon, forest floor carbon, woody debris carbon, stand
individual density, stand basal area, and mean diameter at breast height).
When forced by local climate and the atmospheric CO2 history at each
chronosequence site, the model simulations generally match the observed
CO2 fluxes and carbon stock data well, with model-measurement mean
square root of deviation comparable with the measurement accuracy (for
CO2 flux ~100 g C m−2 yr−1, for biomass carbon
~1000 g C m−2 and for soil carbon ~2000 g C m−2). We find that the current postfire forest carbon sink at the
evaluation sites, as observed by chronosequence methods, is mainly due to a
combination of historical CO2 increase and forest succession. Climate
change and variability during this period offsets some of these expected
carbon gains. The negative impacts of climate were a likely consequence of
increasing water stress caused by significant temperature increases that
were not matched by concurrent increases in precipitation. Our simulation
results demonstrate that a global vegetation model such as ORCHIDEE is able
to capture the essential ecosystem processes in fire-disturbed boreal
forests and produces satisfactory results in terms of both carbon fluxes and
carbon-stock evolution after fire. This makes the model suitable for
regional simulations in boreal regions where fire regimes play a key role in
the ecosystem carbon balance. |
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