Insights into mechanisms governing forest carbon response to nitrogen deposition: a model–data comparison using observed responses to nitrogen addition
dc.contributor.author | Thomas, R. Quinn | en |
dc.contributor.author | Bonan, Gordon B. | en |
dc.contributor.author | Goodale, Christine L. | en |
dc.contributor.department | Forest Resources and Environmental Conservation | en |
dc.date.accessioned | 2017-10-26T14:58:23Z | en |
dc.date.available | 2017-10-26T14:58:23Z | en |
dc.date.issued | 2013-06-17 | en |
dc.description.abstract | In many forest ecosystems, nitrogen (N) deposition enhances plant uptake of carbon dioxide, thus reducing climate warming from fossil fuel emissions. Therefore, accurately modeling how forest carbon (C) sequestration responds to N deposition is critical for understanding how future changes in N availability will influence climate. Here, we use observations of forest C response to N inputs along N deposition gradients and at five temperate forest sites with fertilization experiments to test and improve a global biogeochemical model (CLM-CN 4.0). We show that the CLM-CN plant C growth response to N deposition was smaller than observed and the modeled response to N fertilization was larger than observed. A set of modifications to the CLMCN improved the correspondence between model predictions and observational data (1) by increasing the aboveground C storage in response to historical N deposition (1850–2004) from 14 to 34 kgC per additional kgN added through deposition and (2) by decreasing the aboveground net primary productivity response to N fertilization experiments from 91 to 57 gCm⁻² yr⁻¹. Modeled growth response to N deposition was most sensitive to altering the processes that control plant N uptake and the pathways of N loss. The response to N deposition also increased with a more closed N cycle (reduced N fixation and N gas loss) and decreased when prioritizing microbial over plant uptake of soil inorganic N. The net effect of all the modifications to the CLM-CN resulted in greater retention of N deposition and a greater role of synergy between N deposition and rising atmospheric CO₂ as a mechanism governing increases in temperate forest primary production over the 20th century. Overall, testing models with both the response to gradual increases in N inputs over decades (N deposition) and N pulse additions of N over multiple years (N fertilization) allows for greater understanding of the mechanisms governing C–N coupling. | en |
dc.description.sponsorship | National Science Foundation (NSF) awards to Peter Hess et al. (NSF-ETBC award #1021613) the NSF IGERT in Cross-Scale Biogeochemistry and Climate, and the Cornell Biogeochemistry and Environmental Biocomplexity Small Grant Program financially supported the project | en |
dc.identifier.doi | https://doi.org/10.5194/bg-10-3869-2013 | en |
dc.identifier.uri | http://hdl.handle.net/10919/79798 | en |
dc.identifier.volume | 10 | en |
dc.language.iso | en_US | en |
dc.publisher | Copernicus Publications | en |
dc.rights | Creative Commons Attribution 3.0 United States | en |
dc.rights.uri | http://creativecommons.org/licenses/by/3.0/us/ | en |
dc.title | Insights into mechanisms governing forest carbon response to nitrogen deposition: a model–data comparison using observed responses to nitrogen addition | en |
dc.title.serial | Biogeosciences | en |
dc.type | Article - Refereed | en |
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