Testing an optimality-based model of rooting zone water storage capacity in temperate forests
<p>Rooting zone water storage capacity <i>S</i><sub>r</sub> is a crucial parameter for modeling hydrology, ecosystem gas exchange and vegetation dynamics. Despite its importance, this parameter is still poorly constrained and subject to high uncertainty. We tested th...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2018-07-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/22/4097/2018/hess-22-4097-2018.pdf |
| _version_ | 1818535824128475136 |
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| author | M. J. R. Speich M. J. R. Speich M. J. R. Speich M. J. R. Speich H. Lischke M. Zappa |
| author_facet | M. J. R. Speich M. J. R. Speich M. J. R. Speich M. J. R. Speich H. Lischke M. Zappa |
| author_sort | M. J. R. Speich |
| collection | DOAJ |
| description | <p>Rooting zone water storage capacity <i>S</i><sub>r</sub> is a crucial parameter for
modeling hydrology, ecosystem gas exchange and vegetation dynamics. Despite
its importance, this parameter is still poorly constrained and subject to
high uncertainty. We tested the analytical, optimality-based model of
effective rooting depth proposed by Guswa (2008, 2010) with regard to its
applicability for parameterizing <i>S</i><sub>r</sub> in temperate forests. The
model assumes that plants dimension their rooting systems to maximize net
carbon gain. Results from this model were compared against values obtained by
calibrating a local water balance model against latent heat flux and soil
moisture observations from 15 eddy covariance sites. Then, the effect of
optimality-based <i>S</i><sub>r</sub> estimates on the performance of local water
balance predictions was assessed during model validation.</p><p>The agreement between calibrated and optimality-based <i>S</i><sub>r</sub> varied
greatly across climates and forest types. At a majority of cold and temperate
sites, the <i>S</i><sub>r</sub> estimates were similar for both methods, and the
water balance model performed equally well when parameterized with calibrated
and with optimality-based <i>S</i><sub>r</sub>. At spruce-dominated sites,
optimality-based <i>S</i><sub>r</sub> were much larger than calibrated values.
However, this did not affect the performance of the water balance model. On
the other hand, at the Mediterranean sites considered in this study,
optimality-based <i>S</i><sub>r</sub> were consistently much smaller than
calibrated values. The same was the case at pine-dominated sites on sandy
soils. Accordingly, performance of the water balance model was much worse at
these sites when optimality-based <i>S</i><sub>r</sub> were used. This rooting
depth parameterization might be used in dynamic (eco)hydrological models
under cold and temperate conditions, either to estimate <i>S</i><sub>r</sub>
without calibration or as a model component. This could greatly increase the
reliability of transient climate-impact assessment studies. On the other
hand, the results from this study do not warrant the application of this
model to Mediterranean climates or on very coarse soils. While the cause of
these mismatches cannot be determined with certainty, it is possible that
trees under these conditions follow rooting strategies that differ from the
carbon budget optimization assumed by the model.</p> |
| first_indexed | 2024-12-11T18:30:04Z |
| format | Article |
| id | doaj.art-dd49457d44ab444bb0bba5926a842963 |
| institution | Directory Open Access Journal |
| issn | 1027-5606 1607-7938 |
| language | English |
| last_indexed | 2024-12-11T18:30:04Z |
| publishDate | 2018-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Hydrology and Earth System Sciences |
| spelling | doaj.art-dd49457d44ab444bb0bba5926a8429632022-12-22T00:54:57ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382018-07-01224097412410.5194/hess-22-4097-2018Testing an optimality-based model of rooting zone water storage capacity in temperate forestsM. J. R. Speich0M. J. R. Speich1M. J. R. Speich2M. J. R. Speich3H. Lischke4M. Zappa5Dynamic Macroecology, Swiss Federal Research Institute WSL, 8903 Birmensdorf, SwitzerlandHydrological Forecasts, Swiss Federal Research Institute WSL, 8903 Birmensdorf, SwitzerlandDepartment of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerlandnow at: Biometry and Environmental Systems Analysis, University of Freiburg, 79106 Freiburg i. Br., GermanyDynamic Macroecology, Swiss Federal Research Institute WSL, 8903 Birmensdorf, SwitzerlandHydrological Forecasts, Swiss Federal Research Institute WSL, 8903 Birmensdorf, Switzerland<p>Rooting zone water storage capacity <i>S</i><sub>r</sub> is a crucial parameter for modeling hydrology, ecosystem gas exchange and vegetation dynamics. Despite its importance, this parameter is still poorly constrained and subject to high uncertainty. We tested the analytical, optimality-based model of effective rooting depth proposed by Guswa (2008, 2010) with regard to its applicability for parameterizing <i>S</i><sub>r</sub> in temperate forests. The model assumes that plants dimension their rooting systems to maximize net carbon gain. Results from this model were compared against values obtained by calibrating a local water balance model against latent heat flux and soil moisture observations from 15 eddy covariance sites. Then, the effect of optimality-based <i>S</i><sub>r</sub> estimates on the performance of local water balance predictions was assessed during model validation.</p><p>The agreement between calibrated and optimality-based <i>S</i><sub>r</sub> varied greatly across climates and forest types. At a majority of cold and temperate sites, the <i>S</i><sub>r</sub> estimates were similar for both methods, and the water balance model performed equally well when parameterized with calibrated and with optimality-based <i>S</i><sub>r</sub>. At spruce-dominated sites, optimality-based <i>S</i><sub>r</sub> were much larger than calibrated values. However, this did not affect the performance of the water balance model. On the other hand, at the Mediterranean sites considered in this study, optimality-based <i>S</i><sub>r</sub> were consistently much smaller than calibrated values. The same was the case at pine-dominated sites on sandy soils. Accordingly, performance of the water balance model was much worse at these sites when optimality-based <i>S</i><sub>r</sub> were used. This rooting depth parameterization might be used in dynamic (eco)hydrological models under cold and temperate conditions, either to estimate <i>S</i><sub>r</sub> without calibration or as a model component. This could greatly increase the reliability of transient climate-impact assessment studies. On the other hand, the results from this study do not warrant the application of this model to Mediterranean climates or on very coarse soils. While the cause of these mismatches cannot be determined with certainty, it is possible that trees under these conditions follow rooting strategies that differ from the carbon budget optimization assumed by the model.</p>https://www.hydrol-earth-syst-sci.net/22/4097/2018/hess-22-4097-2018.pdf |
| spellingShingle | M. J. R. Speich M. J. R. Speich M. J. R. Speich M. J. R. Speich H. Lischke M. Zappa Testing an optimality-based model of rooting zone water storage capacity in temperate forests Hydrology and Earth System Sciences |
| title | Testing an optimality-based model of rooting zone water storage capacity in temperate forests |
| title_full | Testing an optimality-based model of rooting zone water storage capacity in temperate forests |
| title_fullStr | Testing an optimality-based model of rooting zone water storage capacity in temperate forests |
| title_full_unstemmed | Testing an optimality-based model of rooting zone water storage capacity in temperate forests |
| title_short | Testing an optimality-based model of rooting zone water storage capacity in temperate forests |
| title_sort | testing an optimality based model of rooting zone water storage capacity in temperate forests |
| url | https://www.hydrol-earth-syst-sci.net/22/4097/2018/hess-22-4097-2018.pdf |
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