Modelling the effect of low soil temperatures on transpiration by Scots pine

The aim of this study was to investigate transpiration and its main driving factors on the example of a hybrid poplar plantation with the clone Populus maximowiczii 9 P. nigra, cv. Max 1 on a site in the hilly loess region of Saxony (Germany). Transpiration was measured using sap flow techniques during the 2007 and 2008 growing season. At the same time, throughfall, soil moisture dynamics and soil physical properties were also measured. Total transpiration rates amounted to 486 mm and 463 mm, respectively, during the 2 years. Maximum daily transpiration rates reached 6.7 mm/day, while an average of 2.2 mm/day for the entire growing season was recorded. The main controlling factors for stand transpiration included the evaporative demand, water availability and soil temperature. The information was implemented into a simple empirical model for the prediction of transpiration. It can be concluded that large-scale establishment of poplar plantations will result in a distinct reduction in groundwater recharge. On the other hand, surface run-off and soil erosion may decrease. Due to limited water availability in the late growing season, the growth potential of the tested clone cannot fully be exploited at many sites in Germany.

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“…The soil temperature response function for water uptake by roots was adapted from Mellander et al (2006) f…”

Section: Data Analysis and Modelling Approachmentioning

confidence: 99%

Transpiration of a hybrid poplar plantation in Saxony (Germany) in response to climate and soil conditions

2010

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“…where the stomata resistance r stomata (-) is calculated as a function of a minimum resistance r smin (-), incoming solar shortwave radiation, vapor pressure deficit and soil water content soil as suggested by Jarvis (1976), and soil temperature T soil following Mellander et al (2006) and Axelsson and Ågren (1976):…”

Section: Aerodynamic Resistancesmentioning

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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“…For example, several weeks of sub-zero temperatures in clay-rich soil are needed to create deep frost (Hänninen et al 2005). Correspondingly, thawing of soil with high water content takes longer and might affect the water and nutrient uptake (e.g., Mellander et al 2006), gas exchange and root and shoot growth of trees. Thus, it may also lead to more pronounced effects on xylem formation than what we observed in this study.…”

Section: Frost Treatment Effects On Xylem Formationmentioning

confidence: 99%

The effects of artificial soil frost on cambial activity and xylem formation in Norway spruce

Jyske¹,

Manner²,

Mäkinen³

et al. 2011

Trees

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We studied the effects of artificial soil frost on cambial activity and xylem formation on 47-year-old Norway spruce [Picea abies (L.) Karst.] trees grown on medium fertile site type (with moraine soil) in eastern Finland (62°42 0 N; 29°45 0 E). Different soil frost treatments applied were: (1) natural snow accumulation and melting (control, CTRL); (2) artificial removal of snow from soil surface during two consecutive winters (OPEN); and (3) snow clearing and insulation (FROST), which was in other ways similar to OPEN, but the ground was insulated in early spring to delay soil thawing. Each treatment was replicated in three blocks, and two sample trees in each plot were repeatedly microcored during growing seasons of 2006-2007 for the analysis of the onset, cessation and the duration of xylem formation. The phases of tracheid differentiation (tracheids in radial enlargement, secondary cell wall formation, and mature tracheids) were measured from the microcores of 2007. The intra-ring growth and wood density variables were analysed based on X-ray densitometry. In FROST in 2006, xylem formation started a week later than in the other treatments. In 2007, no difference was found between the treatments. The discrepancy in results between the two study years may be explained by between-years variation in weather, i.e., the winter was colder in 2005/2006 than in 2006/2007. No effects of soil frost treatments on tracheid differentiation and on most of the intra-ring growth and density variables were discovered. Our results suggest that the delayed thawing of moraine soil may slightly affect the onset, timing and duration of xylem formation in Norway spruce. However, the effects of delayed soil frost may depend also on the soil type and become more evident with increasing water holding capacity of the soil.

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Modelling the effect of low soil temperatures on transpiration by Scots pine

Cited by 49 publications

References 39 publications

Transpiration of a hybrid poplar plantation in Saxony (Germany) in response to climate and soil conditions

Transpiration of a hybrid poplar plantation in Saxony (Germany) in response to climate and soil conditions

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)

The effects of artificial soil frost on cambial activity and xylem formation in Norway spruce

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