Sap flux density (SFD) measurements were used, in combination with morphological characteristics of trees and forest structure, to calculate whole-tree transpiration, stand transpiration (St) and mean canopy stomatal conductance (Gs). Analysis based on the relationships between the morphological cha...
Sap flux density (SFD) measurements were used, in combination with morphological characteristics of trees and forest structure, to calculate whole-tree transpiration, stand transpiration (St) and mean canopy stomatal conductance (Gs). Analysis based on the relationships between the morphological characteristics of trees and whole tree water use, and on the responses of SFD and Gs to short wave radiation (RR), vapor pressure deficit (VPD) and soil water content (SWC) during drought and non-drought periods were conducted. The results showed a strong positive correlation between whole tree transpiration and both tree diameter at breast height (DBH) ($r^2$ = 0.95, P < 0.05) and sapwood area (SA) ($r^2$ = 0.98, P < 0.05). Relationships between SFD and DBH ($r^2$ = 0.25), as well as SA ($r^2$ = 0.17) were weak. Daily SFD of Quercus serrata Thunb was closely related to VPD and RR. Although operating at different time scales, RR and VPD were important interacting environmental controls of tree water use. SFD increased with increasing VPD (<1 kPa) and RR. SWC had a considerable effect on stand transpiration during the drought period. The relationships between SFD, VPD and RR were distorted when SWC dropped below 35%.
Sap flux density (SFD) measurements were used, in combination with morphological characteristics of trees and forest structure, to calculate whole-tree transpiration, stand transpiration (St) and mean canopy stomatal conductance (Gs). Analysis based on the relationships between the morphological characteristics of trees and whole tree water use, and on the responses of SFD and Gs to short wave radiation (RR), vapor pressure deficit (VPD) and soil water content (SWC) during drought and non-drought periods were conducted. The results showed a strong positive correlation between whole tree transpiration and both tree diameter at breast height (DBH) ($r^2$ = 0.95, P < 0.05) and sapwood area (SA) ($r^2$ = 0.98, P < 0.05). Relationships between SFD and DBH ($r^2$ = 0.25), as well as SA ($r^2$ = 0.17) were weak. Daily SFD of Quercus serrata Thunb was closely related to VPD and RR. Although operating at different time scales, RR and VPD were important interacting environmental controls of tree water use. SFD increased with increasing VPD (<1 kPa) and RR. SWC had a considerable effect on stand transpiration during the drought period. The relationships between SFD, VPD and RR were distorted when SWC dropped below 35%.
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문제 정의
An improved understanding of how environmental factors, particularly SWC, RR and VPD influence stand transpiration is necessary in order to predict how these temperate forests may respond to the predicted reductions in precipitation due to climate change. In this study, we examined how the regulation of transpiration in individual trees responded to changes in SWC. We selected the tree species, Quercus serrata, because it is widely distributed in lowland forested areas of the Korean Peninsula.
가설 설정
We selected the tree species, Quercus serrata, because it is widely distributed in lowland forested areas of the Korean Peninsula. We hypothesized that there exists a SWC threshold, which determines critical SFD values under conditions of limited soil water supply. The main objectives of this study were 1) to relate the variability in sap flow to environmental variables; 2) to determine daily and seasonal patterns of stand transpiration, and 3) to investigate how drought affects tree sap flow, and stand transpiration.
제안 방법
An improved understanding of how environmental factors, particularly SWC, RR and VPD influence stand transpiration is necessary in order to predict how these temperate forests may respond to the predicted reductions in precipitation due to climate change. In this study, we examined how the regulation of transpiration in individual trees responded to changes in SWC.
Based on tree location, size, and stem structure, 6 trees of Quercus serrata, were chosen for sap flow measurements. Our strategy was to measure sap flow in trees with a range of diameter at breast heights (DBHs), so as to ensure that the entire stand was represented. In the study year 2007, the growing season for deciduous trees lasted from the beginning of April (bud break) to the beginning of November.
1978). To address the primary objective of this study, it was necessary to relate Gs to RR, SWC and VPD. An empirical relationship between Gs and RR provides a convenient approach to describing the response of stomatal conductance to varying atmospheric conditions (Jarvis 1976, Sandford and Jarvis 1986, Whitehead 1998) (Fig.
대상 데이터
Data were recorded every 30 s and averaged every 30 min with a data logger (DL2; Delta-T Devices, Cambridge, UK). A total of six trees were monitored from 27th April to 5 November 2007, a period that covered bud break to complete senescence.
The study site was at Gwangneung Experimental Forest (GN) located in central western part of the Korean Peninsula (37°44′ N and 127°9′ E), and the elevation of the site is 330 m above sea level.
데이터처리
Estimated SFD and canopy stomatal conductance were correlated with climatic factors such as VPD, RR and SWC. All statistical analyses were performed with Sigma Plot 9.01 and Sigmastat 3.11 program (Systat Software Inc., San Jose, USA).
To evaluate the effect of drought, we calculated the coefficient of determination between SFD and SWC during the drought and non-drought periods. The relationship between SFD and SWC during the drought period was relatively strong (r2 = 0.
이론/모형
Lower transpiration rates should reduce the drought effect, maintaining water potentials at a safe margins above critical values that could lead to cavitation. An optimization procedure was used to establish the values of Gs in the Penman-Monteith equation, giving the closest agreement with measured values of SFD, indicating that Gs was a function of VPD, but dependent, at least to some degree, on SWC.
Sap flux density within the active xylem (SFD) was measured continuously between April and November 2007 using the constant current supply method (Thermal Dissipation Probe) described by Granier (1985, 1987). Each sensor consisted of two, 20 mm long probes (2 mm in diameter), each equipped with a copper constantan thermocouple and wrapped with heating wire (Jung et al.
후속연구
This is however limited by using only one growing season (2007) data, without replicate analysis on the effect of drought on tree water use using multi-year field observation. A further study is therefore necessary to fully elucidate the mechanisms through which drought affects tree sap flow and stand transpiration.
참고문헌 (62)
Bovard BD, Curtis PS, Vogel CS, Su HB, Schmid HP. 2005. Environmental controls on sap flow in a northern hardwood forest. Tree Physiol 25: 31-38.
Breda N, Cochard H, Dreyer E, Granier A. 1993. Water transfer in a mature oak stand (Quercus petraea)-seasonal evolution and effects of a severe drought. Can J For Res 23: 1136-1143.
Cienciala E, Kucera J, Malmer A. 2000. Tree sap flow and stand transpiration of two Acacia mangium plantations in Sabah, Borneo. J Hydrol 236: 109-120.
Cienciala E, Lindroth A. 1995. Gas exchange and sap flow measurements of Salix viminalis trees in short-rotation forest. II. Diurnal and seasonal variations of stomatal response and water use efficiency. Trees 9: 295-301.
Cochard H, Breda N, Granier A. 1996. Whole tree hydraulic conductance and water loss regulation in Quercus during drought: evidence for stomatal control of embolism? Ann For Sci 53: 197-206.
Dierick D, Holscher D. 2009. Species-specific tree water use characteristics in rainforestation stands in the Philippines. Agric For Meteorol 149: 1317-1326.
Epron D, Dreyer E. 1993. Long-term effects of drought on photosynthesis of adult oak trees Quercus petraea (matt) Liebl. and Quercus robur L. in a natural stand. New Phytol 125: 381-389.
Ford CR, Hubbard RM, Kloeppel BD, Vose JM. 2007. A comparison of sap flux-based evapotranspiration estimates with catchment-scale water balance. Agric For Meteorol 145: 176-185.
Garnier E, Berger A. 1987. The influence of drought on stomatal conductance and water potential of peach trees growing in the field. Sci Hortic 32: 249-263.
Goulden ML, Field CB. 1994. Three methods for monitoring the gas exchange of individual tree canopies: ventilatedchamber, sap-flow, and Penman-Monteith measurements on evergreen oaks. Funct Ecol 8: 125-135.
Granier A, Biron P, Kostner B, Gay LW, Najjar G. 1996. Comparisons of xylem sap flow and water vapor flux at the stand level and derivation of canopy conductance for Scots pine. Theor Appl Climatol 53: 115-122.
Granier A, Loustau D, Breda N. 2000. A generic model of forest canopy conductance dependent on climate, soil water availability and leaf area index. Ann For Sci 57: 755-765.
Hinckley TM, Lassoie JP, Running SW. 1978. Temporal and spatial variations in water status of forest trees. For Sci 24: 1-72.
Hinckley TM, Teskey RO, Duhme F, Richter H. 1981. Temperate hardwood forests. In: Water Deficits and Plant Growth. Vol. 6 (Kozlowski TT, ed). Academic Press, New York, pp 153-208.
Hogg EH, Black TA, G den Hartog F, Neumann HH, Zimmermann R, Hurdle PA, Blanken PD, Nesic Z, Yang PC, Staebler RM, McDonald KC, Oren R. 1997. A comparison of sap flow and eddy fluxes of water vapor from a boreal deciduous forest. J Geophys Res 102: 28929-28937.
Hwang T, Kang S, Kim J, Kim Y, Lee D, Band L. 2008. Evaluating drought effect on MODIS Gross Primary Production (GPP) with an eco-hydrological model in the mountainous forest, East Asia. Glob Chang Biol 14: 1037-1056.
Idso SB, Kimball BA, Mauney JR. 1987. Atmospheric carbon dioxide enrichment effects on cotton midday foliage temperature: implications for plant water use and crop yield. Agron J 79: 667-672.
Irvine J, Perks MP, Magnani F, Grace J. 1998. The response of Pinus sylvestris to drought: stomatal control of transpiration and hydraulic conductance. Tree Physiol 18: 393-402.
Jarvis PG. 1976. The interpretation of the variations in leaf water potential and stomatal conductance found in canopies in the field. Philos Trans R Soc Lond B 273: 593-610.
Jung EY, Otieno D, Lee B, Lim JH, Kang SK, Schmidt MWT, Tenhunen J. 2011. Up-scaling to stand transpiration of an Asian temperature mixed-deciduous forest from single tree sapflow measurements. Plant Ecol 212: 383-395.
Kellomaki S, Wang KY. 1996. Photosynthetic responses to needle water potentials in Scots pine after a four-year exposure to elevated $CO_2$ and temperature. Tree Physiol 16: 765-772.
Kellomaki S, Wang KY. 1997. Effects of long-term $CO_2$ and temperature elevation on crown nitrogen distribution and daily photosynthetic performance on Scots pine. For Ecol Manag 99: 309-326.
Kostner BMM, Schulze ED, Kelliher FM, Hollinger DY, Byers JN, Hunt JE, McSeveny TM, Meserth R, Weir PL. 1992. Transpiration and canopy conductance in a pristine broad-leaved forest of Nothofagus: an analysis of xylem sap flow and eddy correlation measurements. Oecologia 91: 350-359.
Kumagai T, Aoki S, Shimizu T, Otsuki K. 2007. Sap flow estimates of stand transpiration at two slope positions in a Japanese cedar forest watershed. Tree Physiol 27: 161-168.
Landsberg JJ, Gower ST. 1997. Applications of Physiological Ecology to Forest Management. Academic Press, Inc., San Diego, CA.
Lee D, Kim J, Kim SJ, Moon SK, Lee J, Lim JH, Son Y, Kang S, Kim S, Kim K, Woo N, Lee B, Kim S. 2007. Lessons from cross-scale studies of water and carbon cycles in the Gwangneung Forest catchment in a complex landscape of monsoon Korea. Korean J Agric For Meteorol 9: 149-160.
Liu X, Zhao P, Rao X, Ma L, Cai X, Zeng X. 2008. Response of canopy stomatal conductance of Acacia mangium forest to environmental driving factors. Front For China 3: 64-71.
Meinzer FC, Goldstein G, Holbrook NM, Jackson P, Cavelier J. 1993. Stomatal and environmental control of transpiration in a lowland tropical forest tree. Plant Cell Environ 16: 439-436.
Monteith JL. 1995. A reinterpretation of stomatal responses to humidity. Plant Cell Environ 18: 357-364.
Nardini A, Pitt F. 1999. Drought resistance of Quercus pubescens as a function of root hydraulic conductance, xylem embolism and hydraulic architecture. New Phytol 143: 485-493.
O'Grady AP, Worledge D, Battaglia M. 2008. Constraints on transpiration of Eucalyptus globulus in southern Tasmania, Australia. Agric For Meteorol 148: 453-465.
Oren R, Pataki DE. 2001. Transpiration in response to variation in microclimate and soil moisture in southeastern deciduous forests. Oecologia 127: 549-559.
Oren R, Phillips N, Katul G, Ewers BE, Pataki DE. 1998. Scaling xylem sap flux and soil water balance and calculating variance: a method for partitioning water flux in forests. Ann For Sci 55: 191-216.
Pataki DE, Oren R. 2003. Species differences in stomatal control of water loss at the canopy scale in a mature bottomland deciduous forest. Adv Water Res 26: 1267-1278.
Pataki DE, Oren R, Phillips N. 1998. Responses of sap flux and stomatal conductance of Pinus taeda L. to stepwise reductions in leaf area. J Exp Bot 49: 871-878.
Sevanto S, Nikinmaa E, Riikoner A, Daley M, Pettijohn JC, Mikkelsen TN, Phillips N, Holbrook NM. 2008. Linking xylem diameter variations with sap flow measurements. Plant Soil 305: 77-90.
Sperry JS, Pockman WT. 1993. Limitation of transpiration by hydraulic conductance and xylem cavitation in Betula occidentalis. Plant Cell Environ 16: 279-287.
Tardieu F, Zhang J, Katerji N, Bethenod O, Palmer S, Davies WJ. 1992. Xylem ABA controls the stomatal conductance of field-grown maize subjected to soil compaction or soil drying. Plant Cell Environ 15: 193-197.
Valentini R, Mugnozza GES, Ehleringer JR. 1992. Hydrogen and carbon isotope ratios of selected species of a Mediterranean macchia ecosystem. Funct Ecol 6: 627-631.
Vertessy RA, Benyon RG, O'sullivan SK, Gribben PR. 1995. Relationships between stem diameter, sapwood area, leaf area and transpiration in a young mountain ash forest. Tree Physiol 15: 559-567.
Wang KY, Kellomaki, Zha T, Peltola H. 2005. Annual and seasonal variation of sap flow and conductance of pine trees grown in elevated carbon dioxide and temperature. J Exp Bot 56: 155-165.
Wartinger A, Heilmeier H, Hartung W, Schulze ED. 1990. Daily and seasonal courses of leaf conductance and abscisic acid in the xylem sap of almond trees [Prunus dulcis (Miller) D. A. Webb] under desert conditions. New Phytol 116: 581-587.
Wilson KB, Hanson PJ, Mulholland PJ, Baldocchi DD, Wullschleger SD. 2001. A comparison of methods for determining forest evapotranspiration and its components: sap-flow, soil water budget, eddy covariance and catchment water balance. Agric For Meteorol 106: 153-168.
Wullschleger SD, Hanson PJ, Todd DE. 2001. Transpiration from a multispecies deciduous forest as estimated by xylem sap flow techniques. For Ecol Manag 143: 205-213.
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