Modeling canopy transpiration using time series analysis: A case study illustrating the effect of soil moisture deficit on Pinus taeda

Ford, Chelcy R.; Goranson, Carol E.; Mitchell, Robert J.; Will, Rodney E.; Teskey, Robert O.

doi:10.1016/j.agrformet.2005.03.004

Cited by 58 publications

(44 citation statements)

References 38 publications

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“…It would be different if imaging and In particular, the daily behavior of T is smoother than that observed for ET, which rapidly varies due to meteorological forces. The observed time lag confirmed the outcomes of other studies [33][34][35]. If there is a large capacitive exchange between the transpiration stream and stem water storage, there is a significant time lag between SF measured at the base of the stem and T (at the canopy leafs).…”

Section: Fluxes Temporal Behaviorsupporting

confidence: 79%

On the Use of the Eddy Covariance Latent Heat Flux and Sap Flow Transpiration for the Validation of a Surface Energy Balance Model

et al. 2018

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Actual evapotranspiration is assessed via surface energy balance at an hourly rate. However, a robust estimation of daily evapotranspiration from hourly values is required. Outcomes of surface energy balance are frequently determined via measures of eddy covariance latent heat flux. Surface energy balance can be applied on images acquired at different times and spatial resolutions. In addition, hourly actual evapotranspiration needs to be integrated at a daily rate for operational uses. Questions arise whether the validation of surface energy balance models can benefit from complementary in situ measures of latent heat flux and sap flow transpiration. Here, validation was driven by image acquisition time, spatial resolution, and temporal integration. Thermal and optical images were collected with a proximity-sensing platform on an olive orchard at different acquisition times. Actual latent heat fluxes from canopy and sap flux at tree trunks were measured with a flux tower and heat dissipation probes. The latent heat fluxes were then further analyzed. A surface energy balance was applied over proximity sensing images re-sampled at different spatial resolutions with resulting latent heat fluxes compared to in situ ones. A time lag was observed and quantified between actual latent heat fluxes from canopy and sap flux at the tree trunk. Results also indicate that a pixel resolution comparable to the average canopy size was suitable for estimating the actual evapotranspiration via a single source surface energy balance model. Images should not be acquired at the beginning or the end of the diurnal period. Findings imply that sap flow transpiration can be used to measure surface energy balance at a daily rate or when images are found at an hourly rate near noon, and the existing time lag between the latent heat flux at the canopy and the sap flow at the trunk does not need to be taken into account.

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Section: Fluxes Temporal Behaviorsupporting

confidence: 79%

On the Use of the Eddy Covariance Latent Heat Flux and Sap Flow Transpiration for the Validation of a Surface Energy Balance Model

et al. 2018

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“…Further details on the sap flow method were reported earlier (Domec et al 2009. To estimate missing sap flux data, we developed time series models predicting daily T from climate variables (vapor pressure deficit and photosynthetically active radiation) according to Ford et al (2005). Missing data resulting from thunderstorms or from probe destruction by bears occurred less than 8% of the time.…”

Section: Components Of Et: Canopy Interception Soil Evaporation Pinmentioning

confidence: 99%

“…For tree species, a shift in ecologic and environmental growing conditions may result in a decline in tree performance and in productivity due to climate change-induced drought stress (Hanson and Weltzin, 2000, Irvine et al 2004, McDowell et al 2008). This consideration is especially true for loblolly pine trees that are responsive to prolonged low soil water content (Oren et al 1998, Ford et al 2005, Domec et al 2009), which decreases tree transpiration, gross primary productivity, and net carbon exchange . Soil water content is the essential state variable in hydrologic studies of Acknowledgments: This study was supported by the USDA Forest Service Raleigh Eastern Forest Environmental Threat Assessment Center cooperative agreements 03-CA-11330147-073 and 04-CA-11330147-238, and the DOE-BER Terrestrial Ecosystem Sciences program, grant 11-DE-SC-0006700.…”

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confidence: 99%

A Comparison of Three Methods to Estimate Evapotranspiration in Two Contrasting Loblolly Pine Plantations: Age-Related Changes in Water Use and Drought Sensitivity of Evapotranspiration Components

Domec¹,

Sun²,

Noormets³

et al. 2012

Forest Science

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Increasing variability of rainfall patterns requires detailed understanding of the pathways of water loss from ecosystems to optimize carbon uptake and management choices. In the current study we characterized the usability of three alternative methods of different rigor for quantifying stand-level evapotranspiration (ET), partitioned ET into tree transpiration (T), understory transpiration, interception, and soil evaporation (E S ) and determined their sensitivity to drought, and evaluated the reliability of soil moisture measurements by taking into account deep soil moisture dynamic. The analyses were conducted in an early-and in a mid-rotation stand of loblolly pine, the predominant species of southern US forest plantations. The three alternative methods for estimating ET were the eddy covariance measurements of water vapor fluxes (ET EC ), the water table fluctuation (ET WT ), and the soil moisture fluctuation (ET SM ). On annual and monthly scales, the three methods agreed to within 10 -20%, whereas on a daily scale, the values of ET SM and ET EC differed by up to 50% and ET SM and ET WT differed by up to 100%. The differences between the methods were attributed to root water extraction below measurement depth and to the sampling at different spatial scales. Regardless of the method used, ET at the early-rotation site was 15-30% lower than that at the mid-rotation site. The dry years did not affect ET at the mid-rotation site but reduced significantly ET at the early-rotation site. Soil moisture trends revealed the importance of measuring water content at several depths throughout the rooting zone because less than 20% of the water is stored in the top 30 cm of soil. Annually, E S represented approximately 9 and 14% of ET EC at the mid-rotation site and the early-rotation site, respectively. At the mid-rotation site, T accounted for approximately 70% of ET EC . Canopy interception was estimated to be 5-10% of annual precipitation and 6 -13% of total ET EC . At the early-rotation site, T accounted for only 35% of ET EC . At this site, transpiration from subdominant trees and shrubs represented 40 -45% of ET EC , indicating that understory was a significant part of the water budget. We concluded that the eddy covariance method is best for estimating ET at the fine temporal scale (i.e., daily), but other soil moisture and water table-based methods were equally reliable and cost-effective for quantifying seasonal ET dynamics. FOR. SCI. 58(5):497-512.Keywords: eddy covariance, loblolly pine, Pinus taeda, sapflow, soil moisture probes, water table L OBLOLLY PINE (PINUS TAEDA L.) REPRESENTS ONE-HALF OF THE STANDING PINE VOLUME in the southern United States (11.7 million ha) and is by far the single most commercially important forest tree species for the region, with more than 1 billion seedlings planted annually (McKeand et al. 2003). More than 1 million ha of intensively managed loblolly pine plantations are found along the lower coastal plain in eastern North Carolina. Large areas of the North Carolina...

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“…Sap flow can only be used as a measure for diurnal transpiration if the measurements are corrected for the time lag with transpiration. A commonly used method to account for the time lag is to artificially shift the sap flow time series to maximize correlation with VPD or radiation (Oren et al, 1999b;Ford et al, 2005).…”

Section: Effects Of Vapour Pressure Deficitmentioning

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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Modeling canopy transpiration using time series analysis: A case study illustrating the effect of soil moisture deficit on Pinus taeda

Cited by 58 publications

References 38 publications

On the Use of the Eddy Covariance Latent Heat Flux and Sap Flow Transpiration for the Validation of a Surface Energy Balance Model

On the Use of the Eddy Covariance Latent Heat Flux and Sap Flow Transpiration for the Validation of a Surface Energy Balance Model

A Comparison of Three Methods to Estimate Evapotranspiration in Two Contrasting Loblolly Pine Plantations: Age-Related Changes in Water Use and Drought Sensitivity of Evapotranspiration Components

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

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