Abstract
Although drought in temperate deciduous forests decreases transpiration rates of many species, stand-level transpiration and total evapotranspiration is often reported to exhibit only minor interannual variability with precipitation. This apparent contradiction was investigated using four years of transpiration estimates from sap flux, interception–evaporation estimates from precipitation and throughfall gauges, modeled soil evaporation and drainage estimates, and eddy covariance data in a mature oak-hickory forest in North Carolina, USA. The study period included one severe drought year and one year of well above-average precipitation. Normalized for atmospheric conditions, transpiration rates of some species were lower in drought than in wet periods whereas others did not respond to drought. However, atmospheric conditions during drought periods are unlike conditions during typical growing season periods. The rainy days that are required to maintain drought-free periods are characterized by low atmospheric vapor pressure deficit, leading to very low transpiration. In contrast, days with low air vapor pressure deficit were practically absent during drought and moderate levels of transpiration were maintained throughout despite the drying soil. Thus, integrated over the growing season, canopy transpiration was not reduced by drought. In addition, high vapor pressure deficit during drought periods sustained appreciable soil evaporation rates. As a result, despite the large interannual variation in precipitation (ranging from 934 to 1346 mm), annual evapotranspiration varied little (610–668 mm), increasing only slightly with precipitation, due to increased canopy rainfall interception. Because forest evapotranspiration shows only modest changes with annual precipitation, lower precipitation translates to decreased replenishment of groundwater and outflow, and thus the supply of water to downstream ecosystems and water bodies.
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References
Addington RN, Donovan LA, Mitchell RJ, Vose JM, Pecot SD, Jack SB, Hacke UG, Sperry JS, Oren R. 2006. Adjustments in hydraulic architecture of Pinus palustris maintain similar stomatal conductance in xeric and mesic habitats. Plant Cell Environ 29:535–45.
Baldocchi DD, Meyers TP. 1991. Trace gas-exchange above the forest floor of a deciduous forest. 1. Evaporation and CO2 efflux. J Geophys Res Atmos 96:7271–85.
Bovard BD, Curtis PS, Vogel CS, Su H-B, Schmid HP. 2005. Environmental controls on sap flow in a northern hardwood forest. Tree Physiol 25:31–8.
Bréda N, Huc R, Granier A, Dreyer E. 2006. Temperate forest trees and stands under severe drought: a review of ecophysiological responses, adaptation processes and long-term consequences. Ann Sci For 63:625–44.
Caldwell MM, Dawson TE, Richards JH. 1998. Hydraulic lift: consequences of water efflux from the roots of plants. Oecologia 113:151–61.
Clapp RB, Hornberger GM. 1978. Empirical equations for some soil hydraulic properties. Water Resour Res 14:601–4.
Daley MJ, Phillips NG. 2006. Interspecific variation in nighttime transpiration and stomatal conductance in a mixed New England deciduous forest. Tree Physiol 26:411–9.
Dawson TE, Burgess SSO, Tu KP, Oliveira RS, Santiago LS, Fisher JB, Simonin KA, Ambrose AR. 2007. Nighttime transpiration in woody plants from contrasting ecosystems. Tree Physiol 27:561–75.
Emerman SH, Dawson TE. 1996. Hydraulic lift and its influence on the water content of the rhizosphere: an example from sugar maple, Acer saccharum. Oecologia 108:273–8.
Ewers BE, Mackay DS, Samanta S. 2007. Interannual consistency in canopy stomatal conductance control of leaf water potential across seven tree species. Tree Physiol 27:11–24.
Granier A. 1987. Sap flow measurements in Douglas fir tree trunks by means of a new thermal method. Ann Sci For 44:1–14.
Hanson PJ, Amthor JS, Wullschleger SD, Wilson KB, Grant RF, Hartley A, Hui D, Hunt ER Jr, Johnson DW, Kimball JS, King AW, Luo Y, McNulty SG, Sun G, Thornton PE, Wang S, Williams M, Baldocchi DD, Cushman RM. 2004. Oak forest carbon and water simulations: model intercomparisons and evaluations against independent data. Ecol Monogr 74:443–89.
Hanson PJ, Huston MA, Todd DE. 2003. Walker branch throughfall displacement experiment. In: Hanson PJ, Wullschleger SD, Eds. North American Temperate Deciduous Forest Responses to Changing Precipitation Regimes. New York: Springer-Verlag. p 8–31.
Hornbeck JW, Martin CW, Eagar C. 1997. Summary of water yield experiments at Hubbard Brook Experimental Forest, New Hampshire. Can J For Res 27:2043–52.
Juang JY, Katul GG, Porporato A, Stoy PC, Siqueira MS, Detto M, Kim HS, Oren R. 2007. Eco-hydrological controls on summertime convective rainfall triggers. Glob Change Biol 13:887–96.
Katul G, Todd P, Pataki D, Kabala ZJ, Oren R. 1997. Soil water depletion by oak trees and the influence of root water uptake on the moisture content spatial statistics. Water Resour Res 33:611–23.
Kim H-S. 2009. Measurement and Modeling of Radiation and Water Fluxes in Plantation Forests. Nicholas School of the Environment and Earth Sciences. Durham, NC: Duke University.
Kim H-S, Oren R, Hinckley TM. 2008. Actual and potential transpiration and carbon assimilation in an irrigated poplar plantation. Tree Physiol 28:559–77.
Köecher P, Gebauer T, Horna V, Leuschner C. 2009. Leaf water status and stem xylem flux in relation to soil drought in five temperate broad-leaved tree species with contrasting water use strategies. Ann For Sci 66, Article No.: 101.
Lu J, Sun G, McNulty SG, Amatya DM. 2005. A comparison of six potential evapotranspiration methods for regional use in the southeastern United States. J Am Water Resour Assoc 41:621–33.
Novick KA, Stoy PC, Katul GG, Ellsworth DS, Siqueira MBS, Juang J-Y, Oren R. 2004. Carbon dioxide and water vapor exchange in a warm temperate grassland. Oecologia 138:259–74.
Oishi AC, Oren R, Stoy PC. 2008. Estimating components of forest evapotranspiration: a footprint approach for scaling sap flux measurements. Agric For Meteorol 148:1719–32.
Oosting HJ. 1942. An ecological analysis of the plant communities of Pidemont, North Carolina. Am Midland Naturalist 28:1–126.
Oren R, Ewers BE, Todd P, Phillips N, Katul GG. 1998. Water balance delineates the soil layer in which moisture affects canopy conductance. Ecol Appl 8:990–1002.
Oren R, Pataki DE. 2001. Transpiration in response to variation in microclimate and soil moisture in southeastern deciduous forests. Oecologia 127:549–59.
Oren R, Sperry JS, Katul G, Pataki DE, Ewers BE, Phillips N, Schafer KVR. 1999. Survey and synthesis of intra- and interspecific variation in stomatal sensitivity to vapour pressure deficit. Plant Cell Environ 22:1515–26.
Oren R, Sperry JS, Ewers BE, Pataki DE, Phillips N, Megonigal JP. 2001. Sensitivity of mean canopy stomatal conductance to vapor pressure deficit in a flooded Taxodium distichum L. forest? hydraulic and non-hydraulic effects. Oecologia 126:21–9.
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 Resour 26:1267–78.
Paul KI, Polglase PJ, O’Connell AM, Carlyle JC, Smethurst PJ, Khanna PK, Worledge D. 2003. Soil water under forests (SWUF): a model of water flow and soil water content under a range of forest types. For Ecol Manage 182:195–211.
Phillips N, Oren R. 2001. Intra- and inter-annual variation in transpiration of a pine forest. Ecol Appl 11:385–96.
Phillips N, Oren R, Zimmermann R. 1996. Radial patterns of xylem sap flow in non-, diffuse- and ring-porous tree species. Plant Cell Environ 19:983–90.
Roberts J. 1983. Forest transpiration—a conservative hydrological process. J Hydrol 66:133–41.
Schäfer KVR, Oren R, Lai C-T, Katul GG. 2002. Hydrologic balance in an intact temperate forest ecosystem under ambient and elevated atmospheric CO2 concentration. Glob Change Biol 8:895–911.
Sinclair TR, Holbrook NM, Zwieniecki MA. 2005. Daily transpiration rates of woody species on drying soil. Tree Physiol 25:1469–72.
Siqueira M, Katul G, Porporato A. 2008. Onset of water stress, hysteresis in plant conductance, and hydraulic lift: scaling soil water dynamics from millimeters to meters. Water Resour Res 44.
Stoy PC, Katul GG, Siqueira MBS, Juang J-Y, Novick KA, McCarthy HR, Oishi AC, Uebelherr JM, Kim H-S, Oren R. 2006. Separating the effects of climate and vegetation on evapotranspiration along a successional chronosequence in the southeastern US. Glob Change Biol 12:2115–35.
Ward EJ, Oren R, Sigurdsson BD, Jarvis PG, Linder S. 2008. Fertilization effects on mean stomatal conductance are mediated through changes in the hydraulic attributes of mature Norway spruce trees. Tree Physiol 28:579–96.
Wear DN, Greis JG. 2002. The southern forest resource assessment summary report. In: Southern Forest Resource Assessment. Gen. Tech. Rep. SRS-53. Wear DN, Greis JG, Eds. US Department of Agriculture, Forest Service, Southern Research Station, Asheville, NC.
Wilson KB, Hanson PJ, Baldocchi DD. 2000. Factors controlling evaporation and energy partitioning beneath a deciduous forest over an annual cycle. Agric For Meteorol 102:83–103.
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 106:153–68.
Wullschleger SD, Hanson PJ. 2003. Sensitivity of sapling and mature-tree water use to altered precipitation regimes. In: Hanson PJ, Wullschleger SD, Eds. North American Temperate Deciduous Forest Responses to Changing Precipitation Regimes. New York: Springer-Verlag.
Wullschleger SD, Hanson PJ. 2006. Sensitivity of canopy transpiration to altered precipitation in an upland oak forest: evidence from a long-term field manipulation study. Glob Change Biol 12:97–109.
Acknowledgements
This Research was supported by the Office of Science (BER) U.S. Department of Energy, Grant No. DE-FG02_00ER63015. We would like to thank P. Stoy, H. McCarthy, H.-S. Kim, B. Poulter, and K. Schäfer for assistance with data collection and analysis, and K. Johnsen and D. D. Richter for unpublished observations on fine roots.
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ACO designed the study, performed research, analyzed data, and wrote the paper. RO designed the study, contributed to data analysis, and wrote the paper. GGK performed data analysis and contributed to writing the paper. KAN helped with analyzing eddy covariance and evaporation data. SP analyzed stream flow data. All authors contributed to the text.
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Oishi, A.C., Oren, R., Novick, K.A. et al. Interannual Invariability of Forest Evapotranspiration and Its Consequence to Water Flow Downstream. Ecosystems 13, 421–436 (2010). https://doi.org/10.1007/s10021-010-9328-3
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DOI: https://doi.org/10.1007/s10021-010-9328-3