Time lags for xylem and stem diameter variations in a Scots pine tree

Sevanto, Sanna; Vesala, Timo; Perämäki, Martti; Nikinmaa, Eero

doi:10.1046/j.1365-3040.2002.00884.x

Cited by 117 publications

(122 citation statements)

References 21 publications

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“…6) and increased the water lost by transpiration (Cermak et al, 2007). During the summer, the recovery phase was not sufficient to replenish the stem from the water lost during the day and trees had to resorted to the internal water storage to keep up the transpiration demands (De Schepper and Steppe, 2010;Sevanto et al, 2002;Zweifel et al, 2001).…”

Section: Seasonal Variation Of Stem Radius and Tree Water Deficit Ovementioning

confidence: 99%

Seasonal and daily cycles of stem radial variation of Pinus pinaster in a drought-prone environment

Vieira

Rossi

Campelo

et al. 2013

Agricultural and Forest Meteorology

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a b s t r a c tHigh resolution measurements of stem diameter variation can provide valuable information on the growth process as well as the tree water status. This study investigates the hourly variations in stem radial increment of maritime pine growing on the west coast of Portugal, under a Mediterranean climate with a pronounced summer drought. We tested the hypotheses that (1) stem radius variation in maritime pine has a daily and seasonal pattern that reflects the availability of water and (2) that once the internal water storage is depleted the tree enters a quiescent state. During 2010, stem radius variations were monitored in four similar trees with automatic dendrometers. Tree water deficit was extracted from the stem radial variation. The stem cycle approach was used to divide the daily cycles into contraction, recovery and increment phases. The seasonal cycle was divided into five periods: winter dormancy, spring growth, pre-summer contraction, summer quiescence and autumn re-hydration. Amplitude and duration of each phase were calculated for each cycle and correlated with precipitation, maximum and minimum temperature. Continuous positive radial increment started in spring and reached its maximum by the end of June. A shrinking period was observed in summer, with amplitudes of contraction and recovery 10 times higher than in the other periods. The inability of the trees to recover from the water lost due to transpiration was responsible for stem shrinking and quiescence observed during summer. In autumn, a period of re-hydration and rapid expansion was observed after precipitation, restoring the tree to a physiologically active state. Daily variations in stem radius of maritime pine were mainly determined by the course of transpiration and thus dependent on temperature and tree water status.

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Section: Seasonal Variation Of Stem Radius and Tree Water Deficit Ovementioning

confidence: 99%

Seasonal and daily cycles of stem radial variation of Pinus pinaster in a drought-prone environment

Vieira

Rossi

Campelo

et al. 2013

Agricultural and Forest Meteorology

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“…In particular the active uploading and unloading of sugars according to Münch's hypothesis (Münch 1928) needs to be considered, because near the sources of sugars considerable water flow from the xylem to the phloem can occur and vice versa close to sugar sinks significant amounts of water can flow from the phloem to the xylem. Locally this water exchange can strongly influence the xylem water flow dynamics which also can lead to xylem diameter changes (Sevanto et al 2002).…”

Section: Discussionmentioning

confidence: 99%

A one-dimensional model of water flow in soil-plant systems based on plant architecture

et al. 2010

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The estimation of root water uptake and water flow in plants is crucial to quantify transpiration and hence the water exchange between land surface and atmosphere. In particular the soil water extraction by plant roots which provides the water supply of plants is a highly dynamic and non-linear process interacting with soil transport processes that are mainly determined by the natural soil variability at different scales. To better consider this root-soil interaction we extended and further developed a finite element tree hydrodynamics model based on the one-dimensional (1D) porous media equation. This is achieved by including in addition to the explicit three- dimensional (3D) architectural representation of the tree crown a corresponding 3D characterisation of the root system. This 1D xylem water flow model was then coupled to a soil water flow model derived also from the 1D porous media equation. We apply the new model to conduct sensitivity analysis of root water uptake and transpiration dynamics and compare the results to simulation results obtained by using a 3D model of soil water flow and root water uptake. Based on data from lysimeter experiments with young European beech trees (Fagus silvatica L.) is shown, that the model is able to correctly describe transpiration and soil water flow. In conclusion, compared to a fully 3D model the 1D porous media approach provides a computationally efficient alternative, able to reproduce the main mechanisms of plant hydro-dynamics including root water uptake from soil.

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“…Because radial permeability is several orders of magnitude smaller than axial permeability (Zwieniecki et al 2001), and because elastic modulus of the phloem is smaller than that of the xylem (Nobel 1991), the radial tension propagation is slower than axial. This explains why diameter changes of the whole stem have been reported to lag behind xylem diameter changes (Sevanto et al 2002). When transpiration ceases, the flow from soil fills up the sapwood quite fast, but the slower recharge of the phloem and bark water storage keeps up a tiny flow and slow tension relaxation during the night hours.…”

Section: Pressure Propagation and Sap Flowmentioning

confidence: 99%

“…The frame temperatures were measured using copper-constantan thermocouples and used to correct for the effect of temperature on the expansion of the frame (Sandvik 1802 Steel). Similar setup has been used by Sevanto et al 2002. …”

Section: Diameter Change Measurementsmentioning

confidence: 99%