Post-fire carbon and nitrogen accumulation and succession in Central Siberia

Markku Larjavaara,Frank Berninger,Marjo Palviainen,Tuomo Wallenius,Anatoly Prokushkin

doi:10.1038/s41598-017-13039-2

Markku Larjavaara, Frank Berninger + Show 3 more

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https://doi.org/10.1038/s41598-017-13039-2

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Abstract

Improved understanding of carbon (C) accumulation after a boreal fire enables more accurate quantification of the C implications caused by potential fire regime shifts. We coupled results from a fire history study with biomass and soil sampling in a remote and little-studied region that represents a vast area of boreal taiga. We used an inventory approach based on predefined plot locations, thus avoiding problems potentially causing bias related to the standard chronosequence approach. The disadvantage of our inventory approach is that more plots are needed to expose trends. Because of this we could not expose clear trends, despite laborious sampling. We found some support for increasing C and nitrogen (N) stored in living trees and dead wood with increasing time since the previous fire or time since the previous stand-replacing fire. Surprisingly, we did not gain support for the well-established paradigm on successional patterns, beginning with angiosperms and leading, if fires are absent, to dominance of Picea. Despite the lack of clear trends in our data, we encourage fire historians and ecosystem scientists to join forces and use even larger data sets to study C accumulation since fire in the complex Eurasian boreal landscapes.

Highlights

Forest fires rapidly release carbon (C) stored in organic material, and may contribute to climate change by increasing atmospheric carbon dioxide (CO2)
Correspondence and requests for materials should be addressed to M.L. www.nature.com/scientificreports/. Another mechanism for how fires influence climate change is through their impacts on nitrogen (N)
Fires decrease N in ecosystems through oxidation and volatilization of N stored in biomass and surface soil[12,13,14], which may have implications on primary production and C sequestration in N-limited boreal forests

Summary

Introduction

Forest fires rapidly release carbon (C) stored in organic material, and may contribute to climate change by increasing atmospheric carbon dioxide (CO2). Boreal forest fires influence climate change, by affecting ecosystem C by altering mean stand age, as described above, and by floristically altering the vegetation[5] and impacting C accumulation, albedo[6,7], volatile organic compound emissions[8] and insulating snow depth impacting permafrost and related emissions[9]. The absence of fires could favour the shade-tolerant but fire-intolerant species (Picea and Pinus sibirica) These floristic shifts could influence the climate, by altering mean C stocks, and via albedo, emissions of volatile organic compound and emissions triggered by melting permafrost. The chronosequence approach has been the standard methodology, which assumes that the time since the last disturbance is the only difference between the studied plots[20]

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