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| Titel |
Derivation of a northern-hemispheric biomass map for use in global carbon cycle models |
| VerfasserIn |
Martin Thurner, Christian Beer, Maurizio Santoro, Nuno Carvalhais, Thomas Wutzler, Dmitry Schepaschenko, Anatoly Shvidenko, Elisabeth Kompter, Shaun Levick, Christiane Schmullius |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250080858
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| Zusammenfassung |
| Quantifying the state and the change of the World’s forests is crucial because of their
ecological, social and economic value. Concerning their ecological importance, forests
provide important feedbacks on the global carbon, energy and water cycles. In
addition to their influence on albedo and evapotranspiration, they have the potential to
sequester atmospheric carbon dioxide and thus to mitigate global warming. The
current state and inter-annual variability of forest carbon stocks remain relatively
unexplored, but remote sensing can serve to overcome this shortcoming. While for
the tropics wall-to-wall estimates of above-ground biomass have been recently
published, up to now there was a lack of similar products covering boreal and temperate
forests.
Recently, estimates of forest growing stock volume (GSV) were derived from ENVISAT
ASAR C-band data for latitudes above 30Ë N. Utilizing a wood density and a biomass
compartment database, a forest carbon density map covering North-America, Europe and
Asia with 0.01Ë resolution could be derived out of this dataset. Allometric functions between
stem, branches, root and foliage biomass were fitted and applied for different leaf
types (broadleaf, needleleaf deciduous, needleleaf evergreen forest). Additionally,
this method enabled uncertainty estimation of the resulting carbon density map.
Intercomparisons with inventory-based biomass products in Russia, Europe and the
USA proved the high accuracy of this approach at a regional scale (r2 = 0.70 –
0.90).
Based on the final biomass map, the forest carbon stocks and densities (excluding
understorey vegetation) for three biomes were estimated across three continents.
While 40.7 ± 15.7 Gt of carbon were found to be stored in boreal forests, temperate
broadleaf/mixed forests and temperate conifer forests contain 24.5 ± 9.4 Gt(C) and
14.5 ± 4.8 Gt(C), respectively. In terms of carbon density, most of the carbon per area is
stored in temperate conifer (62.1 ± 20.7 Mg(C)/ha(Forest)) and broadleaf/mixed forests
(58.0 ± 22.1 Mg(C)/ha(Forest)), whereas boreal forests have a carbon density of only
40.0 ± 15.4 Mg(C)/ha(Forest). While European forest carbon stocks are relatively small, the
carbon density is higher compared to the other continents.
The derived biomass map substantially improves the knowledge on the current carbon
stocks of the northern-hemispheric boreal and temperate forests, serving as a new benchmark
for spatially explicit and consistent biomass mapping with moderate spatial resolution. This
product can be of great value for global carbon cycle models as well as national
carbon monitoring systems. Further investigations concentrate on improving biomass
parameterizations and representations in such kind of models. The presented map will help
to improve the simulation of biomass spatial patterns and variability and enables
identifying the dominant influential factors like climatic conditions and disturbances. |
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