Estimating tree canopy water use via xylem sapflow in an old Norway spruce forest and a comparison with simulation-based canopy transpiration estimates

Köstner, Barbara; Falge, Eva; Alsheimer, Martina; Geyer, Ralf; Tenhunen, John

doi:10.1051/forest:19980108

Cited by 51 publications

(31 citation statements)

References 37 publications

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“…Similar transpiration rates were found in studies on stands of Pinus sylvestris [25] and Picea abies [27]. Comparisons between the two systems installed in the same trees were made on Quercus petraea [20] and Picea abies [26].…”

Section: Introductionsupporting

confidence: 54%

Evaluation of heat balance and heat dissipation methods for sapflow measurements in pine and spruce

2001

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-The tissue heat-balance method (Cÿ ermák) and the heat-dissipation method (Granier) were compared in three Scots pines and two Norway spruces in a forest in central Sweden. The Granier system measured up to 50% lower sapflow than the Cÿ ermák system at high flow rates. New coefficients for the Granier system were estimated, based on sapflow density from the Cÿ ermák measurements. Without compensation, natural temperature gradients may cause large errors in measurements made by the Granier system. By using a horizontal reference sensor, no compensation was necessary. It was also shown that radial flow patterns must be considered when calculating total tree sapflow. Transpiration of two adjacent stands, one measured by the Granier method and the other by the Cÿ ermák method, showed good agreement internally and with total evaporation measured by the eddy-correlation method. THB / HD / sap-flow / transpiration / Picea abies / Pinus sylvestrisRésumé -Évaluation des méthodes des équilibres thermiques et de dissipation thermique concernant la mesure de flux de sève pour le pin et l'épicéa. La méthode des équilibres thermiques (Cÿ ermák), et la méthode de dissipation thermique (Granier) ont été comparées pour trois Pins sylvestres et deux épicéas dans une forêt du centre de la Suède. Le système Granier a donné des valeurs de flux de sève jusqu'à 50 % plus faible que le système Cÿ ermák pour les flux élevés. De nouveaux coefficients basés sur les mesures de densité de flux obtenues avec le système Cÿ ermák ont été estimés pour le système Granier. Le système Granier sans compensation pour les gradients naturels de température dans le tronc peut présenter de larges erreurs, mais si un capteur de référence horizontal est utilisé, les compensations ne sont pas nécessaires. Il a aussi été démontré que les variations radiales de flux doivent être prises en compte lors des calculs de flux de sève pour l'arbre entier. Les transpirations de deux couverts adjacents, l'un mesuré avec la méthode Granier, et l'autre avec la méthode Cÿ ermák, sont en accord entre elles et avec l'évaporation totale mesurée par la méthode des corrélations turbulentes. THB / HD / flux de sève / transpiration / Picea abies / Pinus sylvestris

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Section: Introductionsupporting

confidence: 54%

Evaluation of heat balance and heat dissipation methods for sapflow measurements in pine and spruce

2001

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“…Sap flow methods deal with methodological and integration problems (Köstner et al, 1998) that introduce uncertainty on the measurements. At the tree level, the most important error introducing factors are: non-uniformity of the sap flow along the radius (when radial pattern is neglected), determination of the sapwood depth, positioning of sensors beneath the cambium, possible non-parallelism of inserted needles, differences in xylem heath conductivity and temporal variations.…”

Section: Sap Flow Measurementsmentioning

confidence: 99%

“…Several authors found that the contribution of internal water to transpiration is not a constant in the water budget of trees (Loustau et al, 1996;Köstner et al, 1998;Zweifel et al, 2005;Verbeeck et al, 2007), but changes dynamically from day to day. To determine the complete water balance of a forest ecosystem and its dynamics, it is therefore important to know which factors influence the use of stored water.…”

Section: Introductionmentioning

confidence: 99%

Model analysis of the effects of atmospheric drivers on storage water use in Scots pine

et al. 2007

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Abstract. Storage water use is an indirect consequence of the interplay between different meteorological drivers through their effect on water flow and water potential in trees. We studied these microclimatic drivers of storage water use in Scots pine (Pinus sylvestris L.) growing in a temperate climate. The storage water use was modeled using the ANAFORE model, integrating a dynamic water flow andstorage model with a process-based transpiration model. The model was calibrated and validated with sap flow measurements for the growing season of 2000 (26 May-18 October).Because there was no severe soil drought during the study period, we were able to study atmospheric effects. Incoming radiation and vapour pressure deficit (VPD) were the main atmospheric drivers of storage water use. The general trends of sap flow and storage water use are similar, and follow more or less the pattern of incoming radiation. Nevertheless, considerable differences in the day-to-day pattern of sap flow and storage water use were observed. VPD was determined to be one of the main drivers of these differences. During dry atmospheric conditions (high VPD) storage water use was reduced. This reduction was higher than the reduction in measured sap flow. Our results suggest that the trees did not rely more on storage water during periods of atmospheric drought, without severe soil drought. The daily minimum tree water content was lower in periods of high VPD, but the reserves were not completely depleted after the first day of high VPD, due to refilling during the night.Nevertheless, the tree water content deficit was a third important factor influencing storage water use. When storage compartments were depleted beyond a threshold, storage water use was limited due to the low water potential in the storCorrespondence to: H. Verbeek (hans.verbeeck@ua.ac.be) age compartments. The maximum relative contribution of storage water to daily transpiration was also constrained by an increasing tree water content deficit.

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“…Total [25] and Swanson [74]). HPV methods (early descriptions in Huber and Schmidt [47], Marshall [60] and Swanson [73] [54] and in the daily course of sapflow when both techniques are applied in parallel in the same tree (see figure 2). Com Granier [30,31] [69].…”

mentioning

confidence: 99%

Sapflow measurements in forest stands: methods and uncertainties

Granier²,

1998

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Estimating tree canopy water use via xylem sapflow in an old Norway spruce forest and a comparison with simulation-based canopy transpiration estimates

Cited by 51 publications

References 37 publications

Evaluation of heat balance and heat dissipation methods for sapflow measurements in pine and spruce

Evaluation of heat balance and heat dissipation methods for sapflow measurements in pine and spruce

Model analysis of the effects of atmospheric drivers on storage water use in Scots pine

Sapflow measurements in forest stands: methods and uncertainties

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