Effects of a warmer climate and forest composition on soil carbon cycling, soil organic matter stability and stocks in a humid boreal region
<p>The maintenance of the large soil organic carbon (SOC) stocks of the boreal forest under climate change is a matter of concern. In this study, major soil carbon pools and fluxes were assessed in 22 closed-canopy forests located along an elevation and latitudinal climatic gradient expanding...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-10-01
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| Series: | SOIL |
| Online Access: | https://soil.copernicus.org/articles/8/673/2022/soil-8-673-2022.pdf |
| _version_ | 1811329352982331392 |
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| author | D. Paré J. Laganière G. R. Larocque R. Boutin |
| author_facet | D. Paré J. Laganière G. R. Larocque R. Boutin |
| author_sort | D. Paré |
| collection | DOAJ |
| description | <p>The maintenance of the large soil organic carbon (SOC) stocks of the boreal
forest under climate change is a matter of concern. In this study, major
soil carbon pools and fluxes were assessed in 22 closed-canopy
forests located along an elevation and latitudinal climatic gradient
expanding 4 <span class="inline-formula"><sup>∘</sup></span>C in mean annual temperature (MAT) for two important boreal
conifer forest stand types: balsam fir (<i>Abies balsamea</i>), a fire avoider, and black spruce
(<i>Picea mariana</i>), a fire-tolerant species. SOC stocks were not influenced by a warmer
climate or by forest type. However, carbon fluxes, including aboveground
litterfall rates, as well as total soil respiration (<span class="inline-formula"><i>R</i><sub>s</sub></span>) and heterotrophic
(<span class="inline-formula"><i>R</i><sub>h</sub></span>) and autotrophic soil respiration (<span class="inline-formula"><i>R</i><sub>a</sub></span>), were linearly related
to temperature (cumulative degree days <span class="inline-formula"><i>></i>5</span> <span class="inline-formula"><sup>∘</sup></span>C). The
sensitivity of soil organic matter (SOM) degradation to temperature, assessed by comparing
<span class="inline-formula"><i>Q</i><sub>10</sub></span> (rate of change for a <span class="inline-formula"><i>T</i></span> increase of 10 <span class="inline-formula"><sup>∘</sup></span>C) of soil respiration
and <span class="inline-formula"><i>R</i><sub>s10</sub></span> (soil respiration rates corrected to 10 <span class="inline-formula"><sup>∘</sup></span>C), did not vary
along the temperature gradient, while the proportion of bioreactive carbon
and nitrogen showed higher values for balsam fir and for warmer sites.
Balsam fir forests showed a greater litterfall rate, a better litter quality
(lower C : N ratio) and a higher <span class="inline-formula"><i>R</i><sub>s10</sub></span> than black spruce ones,
suggesting that their soils cycle a larger amount of C and N under a similar
climate regime. Altogether, these results suggest that a warmer climate and
a balsam fir forest composition induce a more rapid SOC turnover. Contrary
to common soil organic matter stabilisation hypotheses, greater litter input
rates did not lead to higher total SOC stocks, and a warmer climate did not
lead to the depletion of bioreactive soil C and N. Positive effects of
warming both on fluxes to and from the soil as well as a potential
saturation of stabilised SOC could explain these results which apply to the
context of this study: a cold and wet environment and a stable vegetation
composition along the temperature gradient. While the entire study area is
subject to a humid climate, a negative relationship was found between
aridity and SOM stocks in the upper mineral soil layer for black spruce
forests, suggesting that water balance is more critical than temperature to
maintain SOM stocks.</p> |
| first_indexed | 2024-04-13T15:42:26Z |
| format | Article |
| id | doaj.art-c0a75ea6f4064360adaf5b2a136dcd30 |
| institution | Directory Open Access Journal |
| issn | 2199-3971 2199-398X |
| language | English |
| last_indexed | 2024-04-13T15:42:26Z |
| publishDate | 2022-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | SOIL |
| spelling | doaj.art-c0a75ea6f4064360adaf5b2a136dcd302022-12-22T02:41:07ZengCopernicus PublicationsSOIL2199-39712199-398X2022-10-01867368610.5194/soil-8-673-2022Effects of a warmer climate and forest composition on soil carbon cycling, soil organic matter stability and stocks in a humid boreal regionD. ParéJ. LaganièreG. R. LarocqueR. Boutin<p>The maintenance of the large soil organic carbon (SOC) stocks of the boreal forest under climate change is a matter of concern. In this study, major soil carbon pools and fluxes were assessed in 22 closed-canopy forests located along an elevation and latitudinal climatic gradient expanding 4 <span class="inline-formula"><sup>∘</sup></span>C in mean annual temperature (MAT) for two important boreal conifer forest stand types: balsam fir (<i>Abies balsamea</i>), a fire avoider, and black spruce (<i>Picea mariana</i>), a fire-tolerant species. SOC stocks were not influenced by a warmer climate or by forest type. However, carbon fluxes, including aboveground litterfall rates, as well as total soil respiration (<span class="inline-formula"><i>R</i><sub>s</sub></span>) and heterotrophic (<span class="inline-formula"><i>R</i><sub>h</sub></span>) and autotrophic soil respiration (<span class="inline-formula"><i>R</i><sub>a</sub></span>), were linearly related to temperature (cumulative degree days <span class="inline-formula"><i>></i>5</span> <span class="inline-formula"><sup>∘</sup></span>C). The sensitivity of soil organic matter (SOM) degradation to temperature, assessed by comparing <span class="inline-formula"><i>Q</i><sub>10</sub></span> (rate of change for a <span class="inline-formula"><i>T</i></span> increase of 10 <span class="inline-formula"><sup>∘</sup></span>C) of soil respiration and <span class="inline-formula"><i>R</i><sub>s10</sub></span> (soil respiration rates corrected to 10 <span class="inline-formula"><sup>∘</sup></span>C), did not vary along the temperature gradient, while the proportion of bioreactive carbon and nitrogen showed higher values for balsam fir and for warmer sites. Balsam fir forests showed a greater litterfall rate, a better litter quality (lower C : N ratio) and a higher <span class="inline-formula"><i>R</i><sub>s10</sub></span> than black spruce ones, suggesting that their soils cycle a larger amount of C and N under a similar climate regime. Altogether, these results suggest that a warmer climate and a balsam fir forest composition induce a more rapid SOC turnover. Contrary to common soil organic matter stabilisation hypotheses, greater litter input rates did not lead to higher total SOC stocks, and a warmer climate did not lead to the depletion of bioreactive soil C and N. Positive effects of warming both on fluxes to and from the soil as well as a potential saturation of stabilised SOC could explain these results which apply to the context of this study: a cold and wet environment and a stable vegetation composition along the temperature gradient. While the entire study area is subject to a humid climate, a negative relationship was found between aridity and SOM stocks in the upper mineral soil layer for black spruce forests, suggesting that water balance is more critical than temperature to maintain SOM stocks.</p>https://soil.copernicus.org/articles/8/673/2022/soil-8-673-2022.pdf |
| spellingShingle | D. Paré J. Laganière G. R. Larocque R. Boutin Effects of a warmer climate and forest composition on soil carbon cycling, soil organic matter stability and stocks in a humid boreal region SOIL |
| title | Effects of a warmer climate and forest composition on soil carbon cycling, soil organic matter stability and stocks in a humid boreal region |
| title_full | Effects of a warmer climate and forest composition on soil carbon cycling, soil organic matter stability and stocks in a humid boreal region |
| title_fullStr | Effects of a warmer climate and forest composition on soil carbon cycling, soil organic matter stability and stocks in a humid boreal region |
| title_full_unstemmed | Effects of a warmer climate and forest composition on soil carbon cycling, soil organic matter stability and stocks in a humid boreal region |
| title_short | Effects of a warmer climate and forest composition on soil carbon cycling, soil organic matter stability and stocks in a humid boreal region |
| title_sort | effects of a warmer climate and forest composition on soil carbon cycling soil organic matter stability and stocks in a humid boreal region |
| url | https://soil.copernicus.org/articles/8/673/2022/soil-8-673-2022.pdf |
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