Biomass and production of two vascular plants in a boreal mesotrophic fen

Saarinen, Timo

doi:10.1139/b96-116

Cited by 150 publications

(141 citation statements)

References 14 publications

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“…Roots of sedges, particularly those of Carex species, extend deep to the soil (Shaver and Cutler, 1979;Saarinen, 1996). Therefore, they have a large contact surface with the anoxic peat.…”

Section: Key Factors For Ch 4 Transport and Oxidationmentioning

confidence: 99%

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HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

et al. 2017

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Abstract. Wetlands are one of the most significant natural sources of methane (CH 4 ) to the atmosphere. They emit CH 4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH 4 , in addition to carbon dioxide (CO 2 ). Production of CH 4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH 4 emissions are thus needed for upscaling observations to estimate present CH 4 emissions and for producing scenarios of future atmospheric CH 4 concentrations. Aiming at a CH 4 model that can be added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH 4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI) of aerenchymatous peatland vegetation, and water table depth (WTD), it simulates the concentrations and transport of CH 4 , CO 2 , and oxygen (O 2 ) in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness), and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH 4 -related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH 4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1) the model is flexible and robust and thus suitable for different environments; (2) the simulated CH 4 emissions largely depend on the prescribed rate of anoxic respiration; (3) the sensitivity of Published by Copernicus Publications on behalf of the European Geosciences Union. 4666M. Raivonen et al.: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands the total CH 4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular, the O 2 concentrations that affect the CH 4 production and oxidation rates; (4) with given input respiration, the peat column description does not significantly affect the simulated CH 4 emissions in this model version.

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“…Roots of sedges, particularly those of Carex species, extend deep to the soil (Shaver and Cutler, 1979;Saarinen, 1996). Therefore, they have a large contact surface with the anoxic peat.…”

Section: Key Factors For Ch 4 Transport and Oxidationmentioning

confidence: 99%

“…The maximum depth that the roots are assumed to reach is 2 m (Saarinen, 1996). If the peat depth exceeds 2 m, there is a rootless zone at the bottom.…”

Section: Peat Geometry Root Distribution and Movement Of Watermentioning

confidence: 99%

HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

et al. 2017

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“…3b), it was still above the soil surface. According to Saarinen (1996), almost 90% of the root biomass is located in the uppermost 30 cm of the peat. So most of the methanogenic substrate, e.g., root substrate and root litter exists in the anaerobic zone.…”

Section: Effects Of Water Table Depth and Peat Temperature On Ch 4 Emmentioning

confidence: 99%

Importance of vegetation classes in modeling CH4 emissions from boreal and subarctic wetlands in Finland

Raivonen

Alekseychik

et al. 2016

Science of The Total Environment

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• CH 4 emission from Finnish wetlands was simulated by CH4MOD wetland .• We recalibrated the vegetation parameters of graminoids, shrubs and Sphagnum.• Simulated CH 4 variations agreed well with the eddy-covariance observations. • Annual CH 4 emissions were reasonably simulated in different years and sites.• Parameterization of different vegetation process was essential in long-term CH 4 estimates. Boreal/arctic wetlands are dominated by diverse plant species, which vary in their contribution to CH 4 production, oxidation and transport processes. Earlier studies have often lumped the processes all together, which may induce large uncertainties into the results. We present a novel model, which includes three vegetation classes and can be used to simulate CH 4 emissions from boreal and arctic treeless wetlands. The model is based on an earlier biogeophysical model, CH4MOD wetland . We grouped the vegetation as graminoids, shrubs and Sphagnum and recalibrated the vegetation parameters according to their different CH 4 production, oxidation and transport capacities. Then, we used eddy-covariance-based CH 4 flux observations from a boreal (Siikaneva) and a subarctic fen , which was consistent with the observations (7-22 g m −2 yr −1 G R A P H I C A L A B S T R A C T a b s t r a c t a r t i c l e i n f o). However, there are some discrepancies between the simulated and observed daily CH 4 fluxes for the Siikaneva site (RMSE = 50.0%) and the Lompolojänkkä site (RMSE = 47.9%). Model sensitivity analysis showed that increasing the proportion of the graminoids would significantly increase the CH 4 emission levels. Our study demonstrated that the parameterization of the different vegetation processes was important in estimating long-term wetland CH 4 emissions.

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“…In boreal forests, on average FRP accounts for 73 % of the total root production and 32 % of the total forest production (Marschner and Rengel 2007). Fine roots also mediate C accumulation as peat in many types of peatlands (Sjörs 1991;Saarinen 1996;Laiho et al 2003). Generally, however, we know little of fine-root-mediated C fluxes in peatlands, the C hotspots of the planet, even though there is indicationreliable C budgets to support greenhouse gas inventories .…”

Section: Introductionmentioning

confidence: 99%

Estimating fine-root production by tree species and understorey functional groups in two contrasting peatland forests

et al. 2016

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Background and aims Estimation of root-mediated carbon fluxes in forested peatlands is needed for understanding ecosystem functioning and supporting greenhouse gas inventories. Here, we aim to determine the optimal methodology for utilizing ingrowth cores in estimating annual fine-root production (FRP) and its vertical distribution in trees, shrubs and herbs. Methods We used 3-year data obtained with modified ingrowth core method and tested two calculation methods: 'ingrowth-dividing' and 'ingrowthsubtracting'. Results The ingrowth-dividing method combined with a 2-year incubation of ingrowth cores can be used for the 'best estimate' of FRP. The FRP in the nutrient-rich fen forest (561 g m −2 ) was more than twice that in the nutrient-poor bog forest (244 g m −2 ). Most FRP occurred in the top 20-cm layer (76-82 %). Tree FRP accounted for 71 % of total FRP in the bog and 94 % in the fen forests, respectively, following the aboveground vegetation patterns; however, in fen forest the proportions of spruce and birch in FRP were higher than their proportions in stand basal area. Conclusions Our methodology may be used to study peatland FRP patterns more widely and will reduce the volume of labour-intensive work, but will benefit from verification with other methods, as is the case in all in situ FRP studies.

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Biomass and production of two vascular plants in a boreal mesotrophic fen

Cited by 150 publications

References 14 publications

HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

Importance of vegetation classes in modeling CH4 emissions from boreal and subarctic wetlands in Finland

Estimating fine-root production by tree species and understorey functional groups in two contrasting peatland forests

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