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Re-assessment of the climatic controls on the carbon and water fluxes of a boreal aspen forest over 1996-2016: changing sensitivity to long-term climatic conditions Liu, Peng; Barr, Alan; Zha, Tianshan; Black, T; Jassal, Rachhpal; Nesic, Zoran; Helgason, Warren; Jia, Xin; Tian, Yun
Description
<b>Abstract</b><br/>
Recent evidence suggests that the relationships between climate and boreal tree growth are generally non-stationary; however, it remains uncertain whether the relationships between climate and carbon (C) fluxes of boreal forests are stationary or have changed over recent decades. In this study, we used continuous eddy-covariance and microclimate data over 21 years (1996-2016) from a 100-year-old trembling aspen stand in central Saskatchewan, Canada to assess the relationships between climate and ecosystem C and water fluxes. Over the study period, the most striking climatic event was a severe, 3-year drought (2001-2003). Gross ecosystem production (GEP) showed larger interannual variability than ecosystem respiration (<em>R</em><sub>e</sub>) over 1996-2016, but <em>R</em><sub>e</sub> was the dominant component contributing to the interannual variation in net ecosystem production (NEP) during post-drought years. The inter-annual variations in evapotranspiration (ET) and C fluxes were primarily driven by temperature and secondarily by water availability. Two-factor linear models combining precipitation and temperature performed well in explaining the inter-annual variation in C and water fluxes (<em>R</em><sup>2</sup>>0.5). The temperature dependence of all three C fluxes (NEP, GEP and <em>R</em><sub>e</sub>) declined over 1996-2015 (<em>p</em><0.05), and as a result, the phenological controls on annual NEP weakened. The decreasing temperature sensitivity of the C fluxes over 1996-2015 may reflect changes in forest structure, related to the over-maturity of the aspen stand at 100-years of age and exacerbated by high tree mortality following the severe 2001-2003 drought. These results may provide an early warning signal of driver shift or even an abrupt status shift of aspen forest dynamics. They may also imply a universal weakening in the relationship between temperature and GEP as forests become over-mature, associated with the structural and compositional changes that accompany forest ageing.</p>
Item Metadata
| Title |
Re-assessment of the climatic controls on the carbon and water fluxes of a boreal aspen forest over 1996-2016: changing sensitivity to long-term climatic conditions
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| Creator | |
| Date Issued |
2022-04-28
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| Description |
<b>Abstract</b><br/>
Recent evidence suggests that the relationships between climate and boreal tree growth are generally non-stationary; however, it remains uncertain whether the relationships between climate and carbon (C) fluxes of boreal forests are stationary or have changed over recent decades. In this study, we used continuous eddy-covariance and microclimate data over 21 years (1996-2016) from a 100-year-old trembling aspen stand in central Saskatchewan, Canada to assess the relationships between climate and ecosystem C and water fluxes. Over the study period, the most striking climatic event was a severe, 3-year drought (2001-2003). Gross ecosystem production (GEP) showed larger interannual variability than ecosystem respiration (<em>R</em><sub>e</sub>) over 1996-2016, but <em>R</em><sub>e</sub> was the dominant component contributing to the interannual variation in net ecosystem production (NEP) during post-drought years. The inter-annual variations in evapotranspiration (ET) and C fluxes were primarily driven by temperature and secondarily by water availability. Two-factor linear models combining precipitation and temperature performed well in explaining the inter-annual variation in C and water fluxes (<em>R</em><sup>2</sup>>0.5). The temperature dependence of all three C fluxes (NEP, GEP and <em>R</em><sub>e</sub>) declined over 1996-2015 (<em>p</em><0.05), and as a result, the phenological controls on annual NEP weakened. The decreasing temperature sensitivity of the C fluxes over 1996-2015 may reflect changes in forest structure, related to the over-maturity of the aspen stand at 100-years of age and exacerbated by high tree mortality following the severe 2001-2003 drought. These results may provide an early warning signal of driver shift or even an abrupt status shift of aspen forest dynamics. They may also imply a universal weakening in the relationship between temperature and GEP as forests become over-mature, associated with the structural and compositional changes that accompany forest ageing.</p> |
| Subject | |
| Type | |
| Notes |
Dryad version number: 4</p> Version status: submitted</p> Dryad curation status: Published</p> Sharing link: https://datadryad.org/stash/share/biP0QhDtoipDC_A1g5dHC-0RyliSpqMP-_AYpNUIxX8</p> Storage size: 105929</p> Visibility: public</p> |
| Date Available |
2022-04-25
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| Provider |
University of British Columbia Library
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| License |
CC0 Waiver
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| DOI |
10.14288/1.0413124
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| URI | |
| Publisher DOI | |
| Grant Funding Agency |
National Key R & D Program of China*
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| Rights URI | |
| Aggregated Source Repository |
Dataverse
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