title: The potential for rising CO2 to account for the observed uptake of carbon by tropical, temperate, and boreal forest biomes.
abstract: We compiled, measured and simulated estimates of NPP and NBP for Amazonian tropical, European temperate, and Siberian Boreal forests from intensive stand-scale field studies, extensive forest biomass inventories, regional atmospheric inversions, and global ecosystem models. We analysed the random and systematic sources of uncertainties pertaining to each approach when comparing their results, and showed that estimates of NPP from different data streams are robustly comparable within their errors. Although NPP increases by a factor of four between Siberia and the Amazon, NBP is larger in Europe than elsewhere, demonstrating that carbon sequestration does not correlate with NPP. We analysed the NPP:NBP ratios in terms of the role of CO2 fertilization. Our results show that the tropical forest NBP carbon sink can be entirely explained by a CO2-induced enhancement of NPP, whereas such a mechanism can only account for 10% of the European sink and up to 50% of Siberian sink. Europe and Siberia are the two regions where factors other than CO, are likely to be dominant in controlling the sequestration of carbon by forest ecosystems, such as management practice, climate, nitrogen deposition, and variation in disturbance regimes.
authors.affiliation: Unité mixte CEA/CNRS, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Ciais
authors.forename: Ivan
authors.initials: I
authors.lastname: Janssens
authors.forename: Anatoly
authors.initials: A
authors.lastname: Shvidenko
authors.forename: Christian
authors.initials: C
authors.lastname: Wirth
authors.forename: Yadvinder
authors.initials: Y
authors.lastname: Malhi
authors.forename: John
authors.initials: J
authors.lastname: Grace
authors.forename: E-Detlef
authors.initials: ED
authors.lastname: Schulze
authors.forename: Martin
authors.initials: M
authors.lastname: Heimann
authors.forename: Oliver
authors.initials: O
authors.lastname: Phillips
authors.forename: A J Han
authors.initials: AJ
authors.lastname: Dolman
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002245:Carbon Dioxide / Q000032:analysis*; D002980:Climate; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods; D017752:Greenhouse Effect; D014197:Trees / Q000254:growth & development / Q000378:metabolism*
chemical_list: D000393:Air Pollutants; D002245:Carbon Dioxide