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| Titel |
Estimates of fire emissions from an active deforestation region in the southern Amazon based on satellite data and biogeochemical modelling |
| VerfasserIn |
G. R. Werf, D. C. Morton, R. S. DeFries, L. Giglio, J. T. Randerson, G. J. Collatz, P. S. Kasibhatla |
| 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 ; 6, no. 2 ; Nr. 6, no. 2 (2009-02-20), S.235-249 |
| Datensatznummer |
250003433
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| Publikation (Nr.) |
 copernicus.org/bg-6-235-2009.pdf |
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| Zusammenfassung |
| Tropical deforestation contributes to the build-up of atmospheric carbon
dioxide in the atmosphere. Within the deforestation process, fire is
frequently used to eliminate biomass in preparation for agricultural use.
Quantifying these deforestation-induced fire emissions represents a
challenge, and current estimates are only available at coarse spatial
resolution with large uncertainty. Here we developed a biogeochemical model
using remote sensing observations of plant productivity, fire activity, and
deforestation rates to estimate emissions for the Brazilian state of Mato
Grosso during 2001–2005. Our model of DEforestation CArbon Fluxes (DECAF)
runs at 250-m spatial resolution with a monthly time step to capture
spatial and temporal heterogeneity in fire dynamics in our study area within
the ''arc of deforestation'', the southern and eastern fringe of the Amazon
tropical forest where agricultural expansion is most concentrated. Fire
emissions estimates from our modelling framework were on average 90 Tg C
year−1, mostly stemming from fires associated with deforestation
(74%) with smaller contributions from fires from conversions of Cerrado
or pastures to cropland (19%) and pasture fires (7%). In terms of
carbon dynamics, about 80% of the aboveground living biomass and litter
was combusted when forests were converted to pasture, and 89% when
converted to cropland because of the highly mechanized nature of the
deforestation process in Mato Grosso. The trajectory of land use change from
forest to other land uses often takes more than one year, and part of the
biomass that was not burned in the dry season following deforestation burned
in consecutive years. This led to a partial decoupling of annual
deforestation rates and fire emissions, and lowered interannual variability
in fire emissions. Interannual variability in the region was somewhat
dampened as well because annual emissions from fires following deforestation
and from maintenance fires did not covary, although the effect was small due
to the minor contribution of maintenance fires. Our results demonstrate how
the DECAF model can be used to model deforestation fire emissions at
relatively high spatial and temporal resolutions. Detailed model output is
suitable for policy applications concerned with annual emissions estimates
distributed among post-clearing land uses and science applications in
combination with atmospheric emissions modelling to provide constrained
global deforestation fire emissions estimates. DECAF currently estimates
emissions from fire; future efforts can incorporate other aspects of net
carbon emissions from deforestation including soil respiration and regrowth. |
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