Preprints
https://doi.org/10.5194/gmd-2021-185
https://doi.org/10.5194/gmd-2021-185

Submitted as: model evaluation paper 01 Jul 2021

Submitted as: model evaluation paper | 01 Jul 2021

Review status: this preprint is currently under review for the journal GMD.

Evaluating an exponential respiration model to alternative models for soil respiration components in a Canadian wildfire chronosequence (FireResp, v1.0)

John Zobitz1,, Heidi Aaltonen2,, Xuan Zhou3,, Frank Beninger3,, Jukka Pumpanen2,, and Kajar Köster4, John Zobitz et al.
  • 1Augsburg University, Minneapolis, Minnesota, United States
  • 2Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
  • 3Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
  • 4Department of Forest Sciences, University of Helsinki, Helsinki, Finland
  • These authors contributed equally to this work.

Abstract. Forest fires modify soil organic carbon and suppress soil respiration for many decades since the initial disturbance. The associated changes in soil autotrophic and heterotrophic respiration from the time of the forest fire however, is less well characterized. We analyzed models of soil autotrophic and heterotrophic respiration with a novel dataset across a fire chronosequence in the Yukon and Northwest Territories of Canada. The dataset consisted of soil incubation experiments and field measurements of soil respiration and soil carbon stocks. The models ranged from a Q10 (exponential) model of respiration to models of heterotrophic respiration using Michaelis-Menten kinetics parameterized with soil microbe carbon. For model evaluation we applied model selection metrics (Akaike Information Criterion) and compared predicted patterns in soil respiration components across the chronosequence. Parameters estimated with data from the 5 cm soil depth had better model-data comparisons than parameters estimated with data from the 10 cm soil depth. The model-data fit was improved by including parameters estimated from soil incubation experiments. Models that incorporated microbial carbon with Michaelis-Menten kinetics reproduced patterns in autotrophic and heterotrophic soil respiration components across the chronosequence. Autotrophic respiration was associated with aboveground tree biomass at more recently burned sites, but this association was less robust at older sites in the chronosequence. Our results provide support for more structured soil respiration models than standard Q10 exponential models.

John Zobitz et al.

Status: open (until 26 Aug 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on gmd-2021-185', Anonymous Referee #1, 29 Jul 2021 reply

John Zobitz et al.

Data sets

FireResp John Zobitz, Heidi Aaltonen, Xuan Zhou, Frank Beninger, Jukka Pumpanen, Kajar Köster https://doi.org/10.5281/zenodo.5037522

Model code and software

CanadaChronoFire John Zobitz, Heidi Aaltonen, Xuan Zhou, Frank Beninger, Jukka Pumpanen, Kajar Köster https://doi.org/10.5281/zenodo.5037522

John Zobitz et al.

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Short summary
Forest fires heavily affect carbon stocks and fluxes of carbon in high-latitude forests. Long-term trends in soil respiration following forest fires are associated with recovery of aboveground biomass. We evaluated models for soil autotrophic and heterotrophic respiration with data from a chronosequence of stand-replacing forest fires in northern Canada. The best model that reproduced expected patterns in soil respiration components takes into account soil microbe carbon as a model variable.