Interactions between snow, canopy, and vegetation in a boreal coniferous forest

Rasmus, Sirpa; Lundell, Robin; Saarinen, Timo

doi:10.1080/17550874.2011.558126

Cited by 34 publications

(30 citation statements)

References 43 publications

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“…While there is less wind-distribution in 220 boreal forests than in the more open tundra, tree composition and density impact snow 221 distribution and depth through interception of snow by the canopy branches and subsequent 222 evaporation and sublimation. This results in lower snow inputs in dense forests and areas of 223 shallow snow underneath individual trees (Rasmus et al, 2011). This winter effect of tree 224 density on snow cover may, in part, explain the negative relationship found between larch stand 225 density and ground thaw (Webb et al, 2017) and is consistent with the effects of winter warming 226 experiments on summertime active layer dynamics (e.g.…”

Section: Vegetation Canopies During the Non-growing Season 190supporting

confidence: 66%

Reviews and syntheses: Changing ecosystem influences on soil thermal regimes in northern high-latitude permafrost regions

Loranty¹,

Abbott²,

Blok³

et al. 2018

Preprint

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<p><strong>Abstract.</strong> Permafrost soils in arctic and boreal ecosystems store twice the amount of current atmospheric carbon that may be mobilized and released to the atmosphere as greenhouse gases when soils thaw under a warming climate. This permafrost carbon climate feedback is among the most globally important terrestrial biosphere feedbacks to climate warming, yet its magnitude remains highly uncertain. This uncertainty lies in predicting the rates and spatial extent of permafrost thaw and subsequent carbon cycle processes. Terrestrial ecosystem influences on surface energy partitioning exert strong control on permafrost soil thermal dynamics and are critical for understanding permafrost soil responses to climate change and disturbance. Here we review how arctic and boreal ecosystem processes influence permafrost soils and characterize key ecosystem changes that regulate permafrost responses to climate. While many of the ecosystem characteristics and processes affecting soil thermal dynamics have been examined in isolation, interactions between processes are less well understood. In particular connections between vegetation, soil moisture, and soil thermal properties affecting permafrost conditions could benefit from additional research. In particular, connections between vegetation, soil moisture, and soil thermal properties affecting permafrost could benefit from additional research. Changes in ecosystem distribution and vegetation characteristics will alter spatial patterns of interactions between climate and permafrost. In addition to shrub expansion, other vegetation responses to changes in climate and disturbance regimes will all affect ecosystem surface energy partitioning in ways that are important for permafrost. Lastly, changes in vegetation and ecosystem distribution will lead to regional and global biophysical and biogeochemical climate feedbacks that may compound or offset local impacts on permafrost soils. Consequently, accurate prediction of the permafrost carbon climate feedback will require detailed understanding of changes in terrestrial ecosystem distribution and function and the net effects of multiple feedback processes operating across scales in space and time.</p>

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Section: Vegetation Canopies During the Non-growing Season 190supporting

confidence: 66%

Reviews and syntheses: Changing ecosystem influences on soil thermal regimes in northern high-latitude permafrost regions

Loranty¹,

Abbott²,

Blok³

et al. 2018

Preprint

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show abstract

“…Snow cover manipulation experiments in arctic and alpine systems generally conWrm our Wndings concerning growth forms with forbs and dwarf shrubs increasing in abundance in response to added snow and late snow melt, whereas lichens and graminoid species show an opposite trend . Likewise, the highest covers of the dwarf shrubs Vaccinium myrtillus and V. vitis-idaea are observed on patches with naturally deep snow cover in an observation of a boreal forest in Finland (Rasmus et al 2011). The importance of snow cover for mosses has still not been well investigated.…”

Section: Discussionmentioning

confidence: 96%

“…Frost damage in understory plants such as Vaccinium myrtillus, however, can strongly increase in mild winters due to reduced insulation, especially in misty and rainy conditions (Ögren 1996), and growth of this species depends on insulation by snow, especially in years with late spring frost events . Observations along natural snow depth gradients at small spatial scales in a boreal forest similar to our study site in terms of species composition indicate a strong inXuence of snow depth on the occurrence of understory plant species in a boreal forest (Rasmus et al 2011). In particular, Vaccinium myrtillus, V. vitis-idaea and the dominant moss Hylocomium splendens prefer microsites with deep snow.…”

Section: Introductionmentioning

confidence: 96%

Absence of snow cover reduces understory plant cover and alters plant community composition in boreal forests

2011

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Snow regimes affect biogeochemistry of boreal ecosystems and are altered by climate change. The effects on plant communities, however, are largely unexplored despite their influence on relevant processes. Here, the impact of snow cover on understory community composition and below-ground production in a boreal Picea abies forest was investigated using a long-term (8-year) snow cover manipulation experiment consisting of the treatments: snow removal, increased insulation (styrofoam pellets), and control. The snow removal treatment caused longer (118 vs. 57 days) and deeper soil frost (mean minimum temperature -5.5 vs. -2.2°C) at 10 cm soil depth in comparison to control. Understory species composition was strongly altered by the snow cover manipulations; vegetation cover declined by more than 50% in the snow removal treatment. In particular, the dominant dwarf shrub Vaccinium myrtillus (-82%) and the most abundant mosses Pleurozium schreberi (-74%) and Dicranum scoparium (-60%) declined strongly. The C:N ratio in V. myrtillus leaves and plant available N in the soil indicated no altered nitrogen nutrition. Fine-root biomass in summer, however, was negatively affected by the reduced snow cover (-50%). Observed effects are attributed to direct frost damage of roots and/ or shoots. Besides the obvious relevance of winter processes on plant ecology and distribution, we propose that shifts in the vegetation caused by frost damage may be an important driver of the reported alterations in biogeochemistry in response to altered snow cover. Understory plant performance clearly needs to be considered in the biogeochemistry of boreal systems in the face of climate change.

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“…Also, the snowpack insulates the underlying soil from winter cold air temperature, with implications for the ecosystem in terms of vegetation cover and dynamics (Rasmus et al, 2011;Grippa et al, 2005), litter decomposition (e.g., Saccone et al, 2013), or carbon cycling (e.g., Kelley et al, 1968). The representation of this insulation is one of the critical uncertainties of the modeling of the global soil carbon cycle and its evolution in permafrost environments (Lawrence and Slater, 2010;Gouttevin et al, 2012).…”

Section: Gouttevin Et Al: a Two-layer Canopy Model With Thermal Imentioning

confidence: 99%

A two-layer canopy model with thermal inertia for an improved snowpack energy balance below needleleaf forest (model SNOWPACK, version 3.2.1, revision 741)

Gouttevin

Lehning

Jonas³

et al. 2015

Geosci. Model Dev.

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Abstract.A new, two-layer canopy module with thermal inertia as part of the detailed snow model SNOWPACK (version 3.2.1) is presented and evaluated. As a by-product of these new developments, an exhaustive description of the canopy module of the SNOWPACK model is provided, thereby filling a gap in the existing literature.In its current form, the two-layer canopy module is suited for evergreen needleleaf forest, with or without snow cover. It is designed to reproduce the difference in thermal response between leafy and woody canopy elements, and their impact on the underlying snowpack or ground surface energy balance. Given the number of processes resolved, the SNOW-PACK model with its enhanced canopy module constitutes a sophisticated physics-based modeling chain of the continuum going from atmosphere to soil through the canopy and snow.Comparisons of modeled sub-canopy thermal radiation to stand-scale observations at an Alpine site (Alptal, Switzerland) demonstrate improvements induced by the new canopy module. Both thermal heat mass and the two-layer canopy formulation contribute to reduce the daily amplitude of the modeled canopy temperature signal, in agreement with observations. Particularly striking is the attenuation of the nighttime drop in canopy temperature, which was a key model bias. We specifically show that a single-layered canopy model is unable to produce this limited temperature drop correctly.The impact of the new parameterizations on the modeled dynamics of the sub-canopy snowpack is analyzed. The new canopy module yields consistent results but the frequent occurrence of mixed-precipitation events at Alptal prevents a conclusive assessment of model performance against snow data.The new model is also successfully tested without specific tuning against measured tree temperature and biomass heatstorage fluxes at the boreal site of Norunda (Sweden). This provides an independent assessment of its physical consistency and stresses the robustness and transferability of the chosen parameterizations.The SNOWPACK code including the new canopy module, is available under Gnu General Public License (GPL) license and upon creation of an account at https://models.slf.ch/.

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Interactions between snow, canopy, and vegetation in a boreal coniferous forest

Cited by 34 publications

References 43 publications

Reviews and syntheses: Changing ecosystem influences on soil thermal regimes in northern high-latitude permafrost regions

Reviews and syntheses: Changing ecosystem influences on soil thermal regimes in northern high-latitude permafrost regions

Absence of snow cover reduces understory plant cover and alters plant community composition in boreal forests

A two-layer canopy model with thermal inertia for an improved snowpack energy balance below needleleaf forest (model SNOWPACK, version 3.2.1, revision 741)

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