scholarly journals On the Use of Sap Flow Measurements to Assess the Water Requirements of Three Australian Native Tree Species

Agronomy ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 52
Author(s):  
Xi Sun ◽  
Jie Li ◽  
Donald Cameron ◽  
Gregory Moore
Keyword(s):  
Soil Moisture ◽  
Tree Species ◽  
Sap Flow ◽  
Potential Evapotranspiration ◽  
Vapour Pressure Deficit ◽  
Weather Conditions ◽  
Pulse Velocity ◽  
Ratio Method ◽  
Flow Volume ◽  
Flow Measurements

The measurement of sap movement in xylem sapwood tissue using heat pulse velocity sap flow instruments has been commonly used to estimate plant transpiration. In this study, sap flow sensors (SFM1) based on the heat ratio method (HRM) were used to assess the sap flow performance of three different tree species located in the eastern suburbs of Melbourne, Australia over a 12-month period. A soil moisture budget profile featuring potential evapotranspiration and precipitation was developed to indicate soil moisture balance while the soil-plant-atmosphere continuum was established at the study site using data obtained from different monitoring instruments. The comparison of sap flow volume for the three species clearly showed that the water demand of Corymbia maculata was the highest when compared to Melaleuca styphelioides and Lophostemon confertus and the daily sap flow volume on the north side of the tree on average was 63% greater than that of the south side. By analysing the optimal temperature and vapour pressure deficit (VPD) for transpiration for all sampled trees, it was concluded that the Melaleuca styphelioides could better cope with hotter and drier weather conditions.

scholarly journals The Dual Method Approach (DMA) Resolves Measurement Range Limitations of Heat Pulse Velocity Sap Flow Sensors

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 46 ◽  
Author(s):  
Michael Forster
Keyword(s):  
Sap Flow ◽  
Entire Range ◽  
Full Range ◽  
Heat Pulse ◽  
Pulse Velocity ◽  
Dual Method ◽  
Ratio Method ◽  
Sap Flux Density ◽  
Flow Measurements ◽  
Method Approach

Sap flow, the movement of fluid in the xylem of plants, is commonly measured with the heat pulse velocity (Vh) family of methods. The observable range of Vh in plants is ~−10 to ~+270 cm/h. However, most Vh methods only measure a limited portion of this range, which restricts their utility. Previous research attempted to extend the range of Vh methods, yet these approaches were analytically intensive or impractical to implement. The Dual Method Approach (DMA), which is derived from the optimal measurement ranges of two Vh methods, the Tmax and the heat ratio method (HRM), also known as the “slow rates of flow” method (SRFM), is proposed to measure the full range of sap flow observable in plants. The DMA adopts an algorithm to dynamically choose the optimal Vh measurement via the Tmax or HRM/SRFM. The DMA was tested by measuring sap flux density (Js) on Tecoma capensis (Thunb.) Lindl., stems and comparing the results against Js measured gravimetrically. The DMA successfully measured the entire range of Vh observed in the experiment from 0.020 to 168.578 cm/h, whereas the HRM/SRFM range was between 0.020 and 45.063 cm/h, and the Tmax range was between 2.049 cm/h and 168.578 cm/h. A linear regression of DMA Js against gravimetric Js found an R2 of 0.918 and error of 1.2%, whereas the HRM had an R2 of 0.458 and an error of 49.1%, and the Tmax had an R2 of 0.826 and an error of 0.5%. Different methods to calculate sapwood thermal diffusivity (k) were also compared with the kVand method showing better accuracy. This study demonstrates that the DMA can measure the entire range of Vh in plants and improve the accuracy of sap flow measurements.

Dynamics of xylem and phloem sap flow in an outdoor zelkova tree visualized by magnetic resonance imaging

2019 ◽  
Vol 40 (3) ◽  
pp. 290-304
Author(s):  
Yasuhiko Terada ◽  
Yusuke Horikawa ◽  
Akiyoshi Nagata ◽  
Katsumi Kose ◽  
Kenji Fukuda
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Cross Section ◽  
Sap Flow ◽  
Diurnal Changes ◽  
Flow Volume ◽  
Resonance Imaging ◽  
Flow Measurements ◽  
Phloem Sap ◽  
Xylem Flow

Abstract Xylem and phloem sap flows in an intact, young Japanese zelkova tree (Zelkova serrata (Thunb.) Makino) growing outdoors were measured using magnetic resonance imaging (MRI). Two propagator-based sequences were developed for q-space imaging: pulse field gradient (PFG) with spin echo (PFG-SE) and stimulated echo (PFG-STE), which were used for xylem and phloem flow measurements, respectively. The data evaluation methods were improved to image fast xylem flow and slow phloem flow. Measurements were taken every 2–3 h for several consecutive days in August 2016, and diurnal changes in xylem and phloem sap flows in a cross-section of the trunk were quantified at a resolution of 1 mm2. During the day, apparent xylem flow volume exhibited a typical diurnal pattern following a vapor pressure deficit. The velocity mapping of xylem sap flow across the trunk cross section revealed that the greatest flow volume was found in current-year earlywood that had differentiated in April–May. The combined xylem flow in the 1- and 2-year-old annual rings also contributed to one-third of total sap flow. In the phloem, downward sap flow did not exhibit diurnal changes. This novel application of MRI in visualization of xylem and phloem sap flow by MRI is a promising tool for in vivo study of water transport in mature trees.

Influence of tree transpiration on mass water balance of mixed mountain forests of the West Carpathians

Biologia ◽  
2006 ◽  
Vol 61 (19) ◽  
Author(s):  
Katarína Střelcová ◽  
Jozef Minďáš ◽  
Jaroslav Škvarenina
Keyword(s):  
Water Balance ◽  
Forest Ecosystem ◽  
Sap Flow ◽  
Potential Evapotranspiration ◽  
Biosphere Reserve ◽  
Flow Measurements ◽  
Tree Transpiration ◽  
Precipitation Total ◽  
Beech Stand ◽  
Snow Precipitation

AbstractBrief information about water balance of the Carpathian temperate forest ecosystem are presented in the paper. Experimental research was done in a mature mixed fir-spruce-beech stand in the research plot “Pol’ana-Hukavský grúň” (850 m a.s.l.) in the south-eastern part of Pol’ana Mts. in the Biosphere Reserve UNESCO in Central Slovakia. Individual parameters of water budget have been continuously monitored. The water consumption of the model beech trees, as well as approximate model beech stand transpiration was estimated on the basis of sap flow measurements and up-scaling through dendrometrical approach. Sap flow of model beech trees was estimated by direct, non-destructive and continuous measurements by tree-trunk heat balance method with internal heating and sensing of temperature. These values were compared with potential evapotranspiration according to Türc. Precipitation parameters (rain and snow precipitation, through-fall precipitation, stem-flow, fog/snow precipitation and infiltration) have been measured simultaneously. Results of mass water balance and the portion of the tree transpiration within the individual water flows are presented. Evapotranspiration of beech-fir forest ecosystem in the middle mountain region (850 m a.s.l.) includes: transpiration (35% of precipitation total), interception (21%), evaporation (8%). There are differences between tree species in mass of transpirated water. Transpiration of spruce and fir reaches two-thirds of beech transpiration. Fog precipitation contribution to the water balance of beech-fir stand is 5%. Concurrently fog precipitation lowers the interception losses of vertical precipitation.

scholarly journals Estimation of transpiration in oil palm (Elaeis guineensis Jacq.) with the heat ratio method

2016 ◽  
Vol 34 (2) ◽  
pp. 172-178 ◽  
Author(s):  
Cristihian Jarri Bayona-Rodríguez ◽  
Hernán Mauricio Romero
Keyword(s):  
Oil Palm ◽  
Sap Flow ◽  
Elaeis Guineensis ◽  
Weather Conditions ◽  
Ratio Method ◽  
Flow Rates ◽  
Young Leaves ◽  
Elaeis Guineensis Jacq ◽  
Xylem Water Flow ◽  
Heat Ratio Method

Sap flow sensors were installed on the leaf petioles of 5-year-old oil palms (Elaeis guineensis Jacq.) to measure the xylem water flow for 12 days based on the heat ratio method (HRM). It was found that young leaves have higher sap flow rates, reaching values of over 250 cm3 h-1, and that sap flow fluctuations are directly related to weather conditions, particularly the vapor pressure deficit (VPD) component. It was observed that the sap flow rates remained constant and very close to 0 cm3 h-1 between 18:00 and 6:00 h and that the upward and downward movement of sap was faster during the day, with peak levels between 9:00 and 16:00 h. Under the evaluation conditions, the oil palm crop transpiration was estimated to be 1.15 mm H2O/ha-day. The HRM is a highly repeatable method and an useful tool to quantify the total oil palm transpiration. It could potentially be applied to irrigation.

scholarly journals Aplicability of sap flow data in hydrological modeling

2021 ◽  
pp. 54-65
Author(s):  
С.Ю. ЛУПАКОВ ◽  
Т.С. ГУБАРЕВА ◽  
В.В. ШАМОВ ◽  
А.В. РУБЦОВ ◽  
Б.И. ГАРЦМАН ◽  
...  
Keyword(s):  
Water Balance ◽  
Sap Flow ◽  
Hydrological Modeling ◽  
Hydrological Model ◽  
Potential Evapotranspiration ◽  
Flow Data ◽  
Water Losses ◽  
Flow Measurements ◽  
Small Catchment ◽  
Daily Evaporation

Статья содержит результаты моделирования стока малого речного бассейна в верховьях р. Уссури с использованием оригинальных данных о стволовом сокодвижении, пересчитанных в объем воды, транспирируемый древостоем. В теплый период 2019 г. на территории Верхнеуссурийского стационара ФНЦ биоразнообразия наземной биоты Восточной Азии ДВО РАН проведен комплекс наблюдений за компонентами влагооборота, позволивший накопить необходимый массив данных для гидрологического моделирования. В дополнение к традиционным водно-балансовым измерениям проводился мониторинг транспирации на основе системы датчиков регистрации водотока в стволах деревьев. Полученные данные точечных наблюдений распространены на масштаб водосбора (площадь около 3.1 км2). Показано, что в теплых и сухих условиях объем суточного суммарного испарения с малого речного бассейна может достигать 8.5 тыс. м3, что больше объема речного стока за тот же период в 5–6 раз, а во время выпадения дождей транспирация деревьев уменьшается практически до нуля. Для расчета водного баланса изучаемого объекта использована гидрологическая модель HBV (Hydrologiska Byråns Vattenbalansavdelning). Ряды суточной потенциальной эвапотранспирации, рассчитанные на основе широко используемых методов Пенмана-Монтейса и Одина, применены в HBV как входные данные. Расчетные суточные значения испарения, по сравнению с полученными на основе данных стволового сокодвижения, оказались выше в 1.5–2 раза, разница сумм испарения за весь теплый период года достигает слоя 100 мм и более. При этом надежной связи между расчетными значениями суточного испарения и измерениями не было обнаружено. Сделан вывод, что использование приборных данных о стволовом сокодвижении в составе входных переменных в гидрологическую модель повышает качество расчетов стока. The article deals with the experience of applying an alternative method for quantifying evapotranspiration volume as input to the hydrological model to simulate runoff of a small catchment located in the upper reaches of the Ussuri River. In the warm period of 2019 at the territory of the Verkhneussuriyskiy station of the Federal Scientific Center of the East Asia Terrestrial Biodiversity (FEB RAS), a set of field measurements was carried out. The measured data were used to calibrate the HBV hydrological model (Hydrologiska Byråns Vattenbalansavdelning). In addition to traditional water-balance measurements, there was assessed the evapotranspiration rate based on sap flow measurements eliminating other parts of water losses. The Tissue Heat Balance technique was applied to measure a sap flow in some individual trees. After that, the obtained data were scaled up to the catchment area (3.1 km2). It is shown that in warm and dry weather conditions, the volume of daily total evaporation from a small catchment can reach 8.5 ths.m3 that is 5-6 times more than the river runoff volume over the same period. During the rainfall events, the transpiration rate in trees decreases to almost zero. To compare the obtained results with the modelled ones, the potential evapotranspiration was also calculated based on well-known Penman-Monteith’s and L. Oudin’s methods that forced HBV model as input. Based on hydrological simulations, these methods overestimated the actual daily evaporation volume up to 2 times in comparison with the sap flow data, and the difference for the warm season reaches 100 mm and more. No reliable relationship was found between the calculated values of daily evaporation rate and the conventionally “measured” ones. Basically, runoff simulations quality was improved while using evapotranspiration volume assessed with the sap flow data. We conclude that water balance via HBV simulations is quite different depending on applied evapotranspiration method. In this case, overestimated volume of evapotranspiration by Penman-Monteith and L. Oudin methods leads to excessive water extraction from the HBV soil moisture storage. If it’s actually not correct, long-term runoff simulations would result in wrong water balance and error accumulation.

Diurnal and inter-day hysteresis of species-specific stomatal conductance from sap-flow measurements illustrates hydraulic-stress responses strategies of trees

2020 ◽  
Author(s):  
Gil Bohrer ◽  
Theresia Yazbeck ◽  
Ana Maria Restrepo Acevedo ◽  
Ashley M. Matheny
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Land Surface ◽  
Sap Flow ◽  
Stress Recovery ◽  
Flow Measurements ◽  
Surface Models ◽  
Stem Water ◽  
Species Specific ◽  
Sap Flow Measurements

<p>Modeling of plant hydraulics is at the forefront of development in vegetation and land-surface models.  Numerical tools that consider water flow within the conductive system of plants, and particularly trees, have been developed and used in studies of hydraulic strategy and consequences of hydraulic behavior for drought tolerance. Several established land-surface models such as ED2, CLM, and E3SM have recently developed “hydro” versions and are ready to extrapolate the consequences of including tree hydraulic behaviors into large scale and global simulations. At the core of any plant hydrodynamic model is the assumption that stomatal conductance is dependent on xylem water potential. Further, “plant hydro” models assume that the effect of soil moisture on stomatal conductance is not direct but cascades through depletion of xylem water content in dry soil conditions.</p><p>We use observations of sap flow, soil moisture, and evapotranspiration at a mixed forest in the University of Michigan Biological Station (UMBS) at the footprint of the US-UMd flux tower to characterize the onset and advancement of hydraulic stress and post-stress recovery. We define stress by observing tree-level decrease of stomatal conductance during sunny days as soil-moisture deficit progresses. We use the Penman-Monteith (PM) formulation to calculate stomatal conductance given observed atmospheric forcing: air temperature, humidity, net radiation, soil heat flux, and aerodynamic resistance. Such PM-based approach effectively decouples changes in evapotranspiration due to atmospheric forcing vs. changes due to decreased stomatal conductance. Multiple years of sap-flow measurements in tens of trees of multiple species allow us to identify the species-specific characteristics of the onset of stress, and the hysteretic dynamics of stomatal conductance. The daily hysteresis indicates the severity of stress. Longer-term inter-day hysteresis of the relationship between noon-time stomatal conductance and soil moisture, before and after rain have alleviated the moisture stress, indicates species-specific strategies of hydraulic-stress recovery. Recovery time is related to the degree of stress, and can vary between a nearly reversible state and 1 to 2 days of recovery, to a long recovery of several days. We find large differences between species in the sensitivity to stress and in the strength of coupling between stem water content and stomatal conductance. These are consistent with the hydraulic strategy of the trees along the an/isohydric continuum.    </p><p>Identifying the hydraulic characteristics of water stress and direct observations of the coupling between stem water storage, conductance, and transpiration provide key observations with which to tune hydrodynamic models and allow process-based functional-type parameterization of stomatal conductance that accounts for tree hydrodynamics and hydraulic stress recovery.   </p>

Evaluating the potential of a novel dual heat-pulse sensor to measure volumetric water use in grapevines under a range of flow conditions

2014 ◽  
Vol 41 (8) ◽  
pp. 874 ◽  
Author(s):  
Kyle R. Pearsall ◽  
Larry E. Williams ◽  
Sean Castorani ◽  
Tim M. Bleby ◽  
Andrew J. McElrone
Keyword(s):  
Water Use ◽  
Sap Flow ◽  
Heat Pulse ◽  
Low Flow ◽  
Ratio Method ◽  
Flow Conditions ◽  
Thompson Seedless ◽  
Flow Measurements ◽  
Highly Correlated ◽  
Weighing Lysimeter

The aim of this study was to validate a novel, dual sap-flow sensor that combines two heat-pulse techniques in a single set of sensor probes to measure volumetric water use over the full range of sap flows found in grapevines. The heat ratio method (HRM), which works well at measuring low and reverse flows, was combined with the compensation heat-pulse method (CHPM) that captures moderate to high flows. Sap-flow measurements were performed on Vitis vinifera L. (cvv. Thompson seedless, Chardonnay and Cabernet Sauvignon) grapevines growing in a greenhouse and in three different vineyards, one of which contained a field weighing lysimeter. The combined heat-pulse techniques closely tracked diurnal grapevine water use determined through lysimetry in two growing seasons, and this was true even at very high flow rates (>6 L vine–1 h–1 for Thompson seedless vines in the weighing lysimeter). Measurements made with the HRM technique under low flow conditions were highly correlated (R2 ~ 0.90) with those calculated using the compensated average gradient method that is used to resolve low flow with the CHPM method. Volumetric water use determined with the dual heat-pulse sensors was highly correlated with hourly lysimeter water use in both years (R2 = 0.92 and 0.94 in 2008 and 2009 respectively), but the nature of the relationship was inconsistent among replicate sensors. Similar results were obtained when comparing grapevine water use determined from sap-flow sensors to miniaturised weighing lysimetry of 2-year-old potted vines and to meteorological estimates for field-grown vines in two additional vineyards. The robust nature of all of the correlations demonstrates that the dual heat-pulse sensors can be used to effectively track relative changes in plant water use, but variability of flow around stems makes it difficult to accurately convert to sap-flow volumes.

scholarly journals Technical note: Long-term probe misalignment and proposed quality control using the heat pulse method for transpiration estimations

2020 ◽  
Vol 24 (5) ◽  
pp. 2755-2767 ◽  
Author(s):  
Elisabeth K. Larsen ◽  
Jose Luis Palau ◽  
Jose Antonio Valiente ◽  
Esteban Chirino ◽  
Juan Bellot
Keyword(s):  
Quality Control ◽  
Sap Flow ◽  
Hydrological Cycle ◽  
Individual Performance ◽  
Ratio Method ◽  
High Temporal Resolution ◽  
Flow Measurements ◽  
Relative Standard ◽  
Sap Flow Measurements

Abstract. Transpiration is a crucial component in the hydrological cycle and a key parameter in many disciplines like agriculture, forestry, ecology and hydrology. Sap flow measurements are one of the most widely used approaches to estimate whole-plant transpiration in woody species; this is due to their applicability in different environments and in a variety of species as well as the fact that continuous high temporal resolution measurements of this parameter are possible. Several techniques have been developed and tested under different climatic conditions and using different wood properties. However, the scientific literature also identifies considerable sources of error when using sap flow measurements that need to be accounted for, including probe misalignment, wounding, thermal diffusivity and stem water content. This study aims to explore probe misalignment as a function of time in order to improve measurements during long-term field campaigns (>3 months). The heat ratio method (HRM) was chosen because it can assess low and reverse flows. Sensors were installed in four Pinus halepensis trees for 20 months. The pines were located in a coastal valley in south-eastern Spain (39∘57′45′′ N 1∘8′31′′ W) that is characterised by a Mediterranean climate. We conclude that even small geometrical misalignments in the probe placement can create a significant error in sap flow estimations. Additionally, we propose that new statistical information should be recorded during the measurement period which can subsequently be used as a quality control of the sensor output. The relative standard deviation and slope against time of the averaged v1v2 were used as quality indicators. We conclude that no general time limit can be set regarding the longevity of the sensors, and this threshold should rather be determined from individual performance over time.

scholarly journals Water-use dynamics of an alien-invaded riparian forest within the summer rainfall zone of South Africa

2019 ◽  
Vol 23 (3) ◽  
pp. 1553-1565
Author(s):  
Bruce C. Scott-Shaw ◽  
Colin S. Everson
Keyword(s):  
South Africa ◽  
Introduced Species ◽  
Water Use ◽  
Sap Flow ◽  
Riparian Forest ◽  
Pulse Velocity ◽  
Ratio Method ◽  
Stem Density ◽  
Indigenous Species ◽  
Selection Of

Abstract. In South Africa the invasion of riparian forests by alien trees has the potential to affect the country's limited water resources. Tree water-use measurements have therefore become an important component of recent hydrological studies. It is difficult for South African government initiatives, such as the Working for Water (WfW) alien clearing programme, to justify alien tree removal and implement rehabilitation unless hydrological benefits are known. The objective of this study was to investigate the water use (transpiration rates) of a selection of introduced and indigenous tree species and quantify the hydrological benefit that could be achieved through a suitable rehabilitation programme. Consequently water use within a riparian forest in the upper Mgeni catchment of KwaZulu-Natal in South Africa was monitored over a 2-year period. The site consisted of an indigenous stand of eastern mistbelt forest that had been invaded by Acacia mearnsii, Eucalyptus nitens and Solanum mauritianum. The heat ratio method of the heat pulse velocity (HPV) sap flow technique and the stem steady state (SSS) techniques were used to measure the sap flow of a selection of indigenous and introduced species. The indigenous trees at New Forest, South Africa, showed clear seasonal trends in the daily sap flow rates varying from 8 to 25 L day−1 in summer (sap flow being directly proportional to tree size). In the winter periods this was reduced to between 3 and 6 L day−1 when limited energy flux was available to drive the transpiration process. The water use in the A. mearnsii and E. grandis trees showed a slight seasonal trend, with a high flow during the winter months in contrast to the indigenous species. The water use in the understorey indicated that multi-stemmed species used up to 12 L day−1. Small alien trees (< 30 mm) A. mearnsii and S. mauritianum used up to 4 L day−1 each. The total accumulated sap flow per year for the three individual A. mearnsii and E. grandis trees was 6548 and 7405 L a−1 respectively. In contrast, the indigenous species averaged 2934 L a−1, clearly demonstrating the higher water use of the introduced species. After spatial upscaling, it was concluded that, at the current state of invasion (21 % of the stand being alien species), the stand used 40 % more water per unit area than if the stand were in a pristine state. If the stand were to be heavily invaded at the same stem density of the indigenous forest, a 100 % increase in water use would occur over an average rainfall year.

Design and testing of an automatic irrigation controller for fruit tree orchards, based on sap flow measurements

2008 ◽  
Vol 59 (7) ◽  
pp. 589 ◽  
Author(s):  
J. E. Fernández ◽  
R. Romero ◽  
J. C. Montaño ◽  
A. Diaz-Espejo ◽  
J. L. Muriel ◽  
...  
Keyword(s):  
Remote Control ◽  
Soil Water ◽  
Sap Flow ◽  
Field Capacity ◽  
Threshold Value ◽  
Pulse Velocity ◽  
Fruit Tree ◽  
Stem Water Potential ◽  
Crop Water ◽  
Flow Measurements

We designed and tested an automatic irrigation control system for fruit tree orchards, designated CRP. At the end of each day, the device calculates the irrigation dose (ID) from sap flow readings in the trunk of trees irrigated to replenish the crop water needs, relative to similar measurements made in over-irrigated trees. It then acts on the pump and electrovalve to supply an ID sufficient to keep the soil close to its field capacity during the irrigation period. Remote control of the system is possible from any computer or Smartphone connected to the Internet. We tested the CRP in an olive orchard in southern Spain. The device was robust and able to filter and amplify the output voltages of the heat-pulse velocity probes and to calculate reliable sap flow data. It calculated and supplied daily irrigation amounts to the orchard according to the specified irrigation protocol. The remote control facility proved to be useful for getting real-time information both on the CRP behaviour and the applied IDs, and for changing parameters of the irrigation protocol. For our conditions, olive trees with big root systems growing in a soil with a remarkable water-holding capacity, the approach mentioned above for calculating ID had not enough resolution to replace the daily crop water consumption. The device, however, was able to react when the soil water content fell below the threshold for soil water deficit. The threshold value was identified with simultaneous measurements of stem water potential in the instrumented trees. Our results suggest a change in the irrigation protocol that will allow the CRP to apply a recovery irrigation whenever that threshold is reached, making the device suitable for applying a deficit irrigation strategy in the orchard.

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