Sap flow measurements with some thermodynamic methods, flow integration within trees and scaling up from sample trees to entire forest stands

Čermák, Jan; Kučera, Jiří; Nadezhdina, Nadezhda

doi:10.1007/s00468-004-0339-6

Cited by 347 publications

(175 citation statements)

References 103 publications

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“…For computing stand transpiration from xylem sap flux density (SFD) measurements it is appropriate to group all trees of the stand according to diameter-or area classes [1,2,4,17]. Diurnal values of transpiration of individual trees are then a stratified random sample, the transpiration in mm being calculated from them via the basal area of the stand [5].…”

Section: Discussionmentioning

confidence: 99%

Radial distribution of sap flux density in trunks of a mature beech stand

Lüttschwager

Remus

2007

Ann. For. Sci.

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-In a mature beech stand located in north-eastern Germany, xylem sap flux measurements were continuously performed during the 2002−2004 growing seasons. Ten representative trunks were studied using heated thermal dissipation probes. The measurements aimed at identifying principles governing radial profiles of xylem flux in beech trunks. The measurements were taken up to a trunk depth of 132 mm. The sap flow density in the pericambial xylem was found to vary among trees of different diameters, but was not considerably smaller in suppressed trees. A model for the radial distribution of sap flux density was formulated relating trunk radius and sap flow density. The model takes into account different trunk diameter. About 90% of the sap flux was found to occur in the outer two fifths of the trunk. Using this model, an adequate estimate of transpiration can be achieved at tree and stand level, even when the sap flux measurements are restricted to the outer trunk sectors. Les mesures ont été réalisées jusqu'à une profondeur de 132 mm. La densité de flux de sève du xylème de la zone cambiale variait d'arbre en arbre en fonction du diamètre, mais cette densité ne diminuait pas sensiblement dans les arbres dominés. Un modèle de distribution radiale de la densité de flux de sève a été mis au point dans lequel le diamètre du tronc et la densité du flux de sève sont mis en relation. Le modèle prend en considération les arbres ayant des troncs de diamètres différents. Environ 90 % de l'eau circule dans les deux cinquièmes extérieurs du tronc. De cette façon, il est possible de calculer de manière suffisamment exacte la transpiration de l'arbre ou du peuplement tout entier, même si les mesures du flux de sève se limitent à la zone externe du tronc. densité de flux de sève / modèle radial / hêtre

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Section: Discussionmentioning

confidence: 99%

Radial distribution of sap flux density in trunks of a mature beech stand

Lüttschwager

Remus

2007

Ann. For. Sci.

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“…Spatial and vertical leaf area index in deciduous trees have been analyzed many times previously using plan canopy analyzers or destructive sampling (e.g., [5][6][7]12,16,17,22,23,26]). Our geometrical model simplifies crown shapes and supposes homogenous leaf distribution within the foliated canopy volume; there seems little advantage in a more complex model because of the tree variability.…”

Section: Geometrical Model and Image Analysismentioning

confidence: 99%

“…eddy covariance [20,27]), soil geophysical [1,8,13] and physiological (e.g. stomatal conductance and sap-flow [6,9,18]) measurements relating to transpiration and water use from the orchard.…”

Section: Introductionmentioning

confidence: 99%

Dendrométrie et distribution de la surface foliaire dans une vieille oliveraie près d’Andria, dans le sud de l’Italie

et al. 2007

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-The objectives of this paper were (1) to provide general biometry data for an 80-year-old olive (Olea europea L., cv. Coratina) grove in Andria, southern Italy, and (2) to compare different methods for estimating leaf area distributions. Stand biometry was represented by a stocking density of 132 trees ha −1 , mean spacing of 8.7 m and mean social area (proportional to spacing and tree size) of about 76 m 2 per tree. Trunk total circumference averaged 110 cm and after subtraction of missing or dead parts of stems averaged 81 cm, projected area of crowns averaged 17.7 m 2 and the mean tree height was 4.9 m. Leaf distribution was evaluated using calibrated ground-based side photographs through image analysis and through using a simple canopy-layer model (considering hollow volume within tree crowns) and double-Gaussian curves. The mean leaf size was about 5 cm 2 (distributed in a log-normal manner over the range of 2 to 12 cm 2 ). Considering whole tree crowns, the mean leaf density was about 2.6 m 2 m −3 ; the maximum leaf area occurred in canopy layers between 1.5 to 3 m, tailing with a steeper slope to the crown base and a less steep slope to the tree-top. The foliated volume of olive crowns (mean 33.2 m 3 ) contained on average 145 thousand leaves of the total area of 72.6 m 2 . The corresponding leaf area index on the stand level (LAI grove = 0.96), was rather low due to low stocking density. However when taking into account only the projected crown areas (and avoiding free space between trees), the mean LAI reached about 3.5 (range from 1-7). The radial pattern of leaf distribution derived from image analysis indicated peak LAI rad values at a distance from the stem of about 60 to 70% of crown radius in trees of different size. The applicability of different approaches to the estimation of the necessary allometric parameters is discussed.contour side photography / image analysis / geometrical modeling / vertical and radial leaf distribution / stem damage / crown form / biometry Résumé -Dendrométrie et distribution de la surface foliaire dans une vieille oliveraie près d'Andria, dans le sud de l'Italie. L'objectif de ce travail a été d'obtenir des données biométriques générales pour une vieille oliveraie de 80 ans (Olea europea L., cv. Coratina) installée près d'Andria, dans le sud de l'Italie, et de comparer différentes méthodes d'estimation de la surface foliaire. L'oliveraie comportait 132 arbres à l'hectare avec un espacement moyen de 8,7 m et une surface sociale moyenne (proportionnelle à l'espacement et à la taille des arbres) d'environ 76 m 2 par arbre. La circonférence des arbres atteignait en moyenne 110 cm et, après soustraction des disparus ou des parties mortes des troncs, elle atteignait en moyenne 81 cm. La surface projetée des couronnes atteignait en moyenne 17,7 m 2 et la hauteur moyenne des arbres était de 4,9 m. La distribution des feuilles a été évaluée en utilisant (i) un système de photographies à partir du sol suivies d'une analyse d'images, et (ii) un modèle simple de stratifi...

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“…Five oak branches and two male mistletoe plants were selected for sap flow measurements using the heat field deformation (HFD) method (Nadezhdina et al 1998;Čermák et al 2004;Steppe et al 2010), which accounts for the size and overall distribution of the branches in the crown. Given the small size of the oak and mistletoe branches, the sap flow rate was only measured at one depth, 2-3 mm below the cambium, by single-point HFD sensors (Dendronet, Inc. Brno, Czech Republic).…”

Section: Sap Flowmentioning

confidence: 99%

Transpiration and stomatal conductance of mistletoe (Loranthus europaeus) and its host plant, downy oak (Quercus pubescens)

et al. 2012

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Sap flow rate was measured in the crown of a solitary specimen of downy oak (Quercus pubescens) infested by mistletoe (Loranthus europaeus). Five oak branches and two mistletoe plants were selected for analysis. The seasonal sum of transpired water expressed per leaf area unit was five times higher in the mistletoe than in the oak. In addition, the diurnal curves of sap flow were different between the plants. In the morning, the sap flow measured in the mistletoe lagged one hour behind the sap flow measured in an oak branch unencumbered by mistletoe. In contrast, no time lag was observed in the evening. The proportion of water transpired at night relative to the total transpiration was 7% in both species. The stomatal conductances derived from the inverted Penman-Monteith equation and their dependence on global radiation and the vapour pressure deficit (D) revealed that D exerts a different behaviour in stomatal control of transpiration in the mistletoe. We also determined that the concentration of calcium in the leaf mass could serve as a proxy for transpiration rate, however the relationship was not proportional.

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Sap flow measurements with some thermodynamic methods, flow integration within trees and scaling up from sample trees to entire forest stands

Cited by 347 publications

References 103 publications

Radial distribution of sap flux density in trunks of a mature beech stand

Radial distribution of sap flux density in trunks of a mature beech stand

Dendrométrie et distribution de la surface foliaire dans une vieille oliveraie près d’Andria, dans le sud de l’Italie

Transpiration and stomatal conductance of mistletoe (Loranthus europaeus) and its host plant, downy oak (Quercus pubescens)

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