Tree canopy and herb layer transpiration in three Scots pine stands with different stand structures

Lüttschwager, Dietmar; Rust, Steffen; Wulf, Monika; Forkert, Jacqueline; Hüttl, Reinhard F.

doi:10.1051/forest:19990401

Cited by 28 publications

(20 citation statements)

References 14 publications

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“…The transpiration part (measured by the sapflow techniques) of the total evaporation, E tot measured by the eddy-correlation system, was 74% (ΣE comp / (ΣE tot ) and 61% (ΣE test / (ΣE tot ) for all days with transpiration above 1 mm day -1 . This is in the same range as reported for water balance studies in other coniferous forest [19,22,31] …”

Section: Comparison Of the Two Systemssupporting

confidence: 70%

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: Comparison Of the Two Systemssupporting

confidence: 70%

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

2001

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“…Estimates of stand transpiration in other similar Scots pine stands from central and northern Europe are certainly lower than the values found in this study. Growing season values range from less than 100 mm (Lüttschwager et al, 1999) to an upper limit around 300 mm (Jaeger and Kessler, 1996), the latter figure obtained as a long-term average. Modelling approaches yield values of yearly transpiration of about 230 mm in a Belgian stand (Meiresonne et al, 2003) or intervals for southern Europe forests between 200 and 450 mm year −1 (Berninger, 1997 Table 4).…”

Section: Differences In Stand-level Transpiration Between Pinementioning

confidence: 99%

Transpiration of montane Pinus sylvestris L. and Quercus pubescens Willd. forest stands measured with sap flow sensors in NE Spain

Poyatos

Llorens

Gallart

2005

Hydrol. Earth Syst. Sci.

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Abstract. Stand transpiration was measured during the 2003 and 2004 growing seasons using heat dissipation sap flow sensors in a Scots pine (Pinus sylvestris L.) and a pubescent oak (Quercus pubescens Willd.) forests located in a montane area of the Eastern Pyrenees (NE Spain). The first aim of the study was to assess the differences in quantitative estimates of transpiration (E c ) and the response to evaporative demand of the two stands. Over the studied period of 2003, characterised by a severe drought episode during the summer, the oak stand E c was only 110 mm compared to the 239 mm transpired by the Scots pine stand, although the ratio of transpiration to reference evapotranspiration (E c /ET 0 ) in the oak stand compares well with the expected values predicted for low leaf area index (LAI) oak forests in southern Europe. Scots pine showed a strong reduction in E c /ET 0 as the drought developed, whereas pubescent oak was less affected by soil moisture deficits in the upper soil. As a second objective, and given the contrasting meteorological con-

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“…This is in spite of the fact that, depending on the species, autors demonstrated considerable if variable effects on photosynthesis, respiration, transpiration and growth. Soil temperatures below 7°C reduce photosynthesis and transpiration, probably due to an increase in water viscosity, while a reduction in growth could be due to a reduction in the hormone supply combined with an increase in ABA production [70].…”

Section: The Influence Of Forest Cover On the Microclimatementioning

confidence: 99%

Interactions between forest stands and microclimate: Ecophysiological aspects and consequences for silviculture

2000

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-At a local scale, forest trees and stands have a marked influence on climate; thus it is possible to define microclimates. These effects depend on local climatic characteristics and stand type. All climatic parameters should be considered, but particular attention should be paid to temperature, light and water. From a silvicultural point of view knowledge of the interactions existing between microclimatic conditions and stands, in conjunction with information now available concerning tree ecophysiology make it possible to produce viable applications which are useful for silviculture during stand formation, and for applying silvicultural treatments. Whitout a doubt, taking forest cover interactions into account (climate and ecophysiological potential of species) is the basis of sustainable management in forests. Based on the current knowledge about young stands, it is possible to use existing vegetation cover, in a more or less modified form, to improve temperature conditions especially in relation to spring frost damage, and to improve water conditions for both plant uptake and plant growth for a variable period depending on the species, but for a minimum of 4 to 5 years. For clearing and thinning, the effects of microclimatic changes created by this type of forestry management, and consequently the response of trees in terms of photosynthesis and growth, are now well defined.forest stands / microclimate / ecophysiology / silviculture Résumé -Interactions entre peuplements forestiers et microclimat : aspect écophysiologique et conséquences pour la sylviculture. Les arbres et les peuplements forestiers exercent, au niveau local, des influences notables sur le climat ; on peut alors définir des microclimats. Ces influences sont dépendantes des caractéristiques du climat local et des types de peuplement. L'ensemble des paramètres climatiques sont à considérer, mais une attention particulière doit être portée à la température, à la lumière et à l'eau. Au plan sylvicole la connaissance des interactions existant entre conditions microclimatiques et peuplements, couplées aux informations maintenant disponibles concernant l'écophysiologie des arbres permettent de déboucher sur des applications fiables, utilisables par la sylviculture pour la création des peuplements et la mise en oeuvre des traitements sylvicoles. Incontestablement la prise en compte des interactions couvert forestier -climat et potentialités écophysiologiques des essences est à la base d'une gestion durable des forêts. Sur la base des connaissances actuelles et pour ce qui concerne les jeunes peuplements, il est possible d'utiliser le couvert végétal préexistant, plus ou moins modifié, pour améliorer les conditions thermiques notamment au plan des risques de dégâts de gel au printemps et pour améliorer les conditions hydriques tant pour ce qui concerne la reprise que la croissance des plants pendant une période variable selon les espèces, mais d'une durée minimale de 4 à 5 ans. Pour les dégagements et éclaircies l'effet des modifications micr...

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Tree canopy and herb layer transpiration in three Scots pine stands with different stand structures

Abstract: -To evaluate the impact of herb layer structure on the transpiration of Scots pine ecosystems in north-eastern Germany, we measured tree canopy and herb layer transpiration in three stands. Parameters

Cited by 28 publications

References 14 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

Transpiration of montane Pinus sylvestris L. and Quercus pubescens Willd. forest stands measured with sap flow sensors in NE Spain

Interactions between forest stands and microclimate: Ecophysiological aspects and consequences for silviculture

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