Variability of tree transpiration across three zones in a southeastern U.S. Piedmont watershed

Quantifying species-specific tree transpiration across watershed zones is important for estimating watershed evapotranspiration (ET) and predicting drought effects on vegetation. The objectives of this study are to 1) assess sap flux density (Js) and tree-level transpiration (Ts) across three contrasting zones (riparian buffer, mid-hillslope, and upland-hillslope), 2) determine how species-specific Js responds to vapor pressure deficit (VPD), and 3) compare watershed-level transpiration (Tw) derived from each zone. We measured Js and Ts in eight tree species in the three zones in a 12-ha forested watershed. In the dry year of 2015, loblolly pine (Pinus taeda), Virginia pine (Pinus virginiana), and sweetgum (Liquidambar styraciflua) Js rates were significantly higher in the buffer when compared to the other two zones. In contrast, Js in tulip poplar (Liriodendron tulipifera) and red maple (Acer rubrum) were significantly lower in the buffer than in the mid-hillslope. Daily Ts varied by zone and ranged from 10 to 93 liters in the dry year and 9 to 122 liters in the wet year. Js responded nonlinearly to VPD in all trees and zones. Annual Tw based on scaled-Js data was 447 mm, 377 mm, and 340 mm for the buffer, mid-hillslope, and upland-hillslope, respectively. We conclude that large spatial variability in Js and scaled Tw were driven by differences in soil moisture at each zone and forest composition. Consequently, spatial heterogeneity of vegetation and soil moisture must be considered when accurately quantifying watershed level ET.

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Tree Water Dynamics in a Semi-Arid, Pinus brutia Forest

Water ◽

10.3390/w10081039 ◽

2018 ◽

Vol 10 (8) ◽

pp. 1039 ◽

Cited By ~ 7

Author(s):

Marinos Eliades ◽

Adriana Bruggeman ◽

Hakan Djuma ◽

Maciek Lubczynski

Keyword(s):

Soil Moisture ◽

Sap Flow ◽

Water Dynamics ◽

Hydraulic Redistribution ◽

Sap Flux ◽

Sap Flux Density ◽

Pinus Brutia ◽

Soil Moisture Sensors ◽

Air Temperatures ◽

Semi Arid

This study aims to examine interactions between tree characteristics, sap flow, and environmental variables in an open Pinus brutia (Ten.) forest with shallow soil. We examined radial and azimuthal variations of sap flux density (Jp), and also investigated the occurrence of hydraulic redistribution mechanisms, quantified nocturnal tree transpiration, and analyzed the total water use of P. brutia trees during a three-year period. Sap flow and soil moisture sensors were installed onto and around eight trees, situated in the foothills of the Troodos Mountains, Cyprus. Radial observations showed a linear decrease of sap flux densities with increasing sapwood depth. Azimuthal differences were found to be statistically insignificant. Reverse sap flow was observed during low vapor pressure deficit (VPD) and negative air temperatures. Nocturnal sap flow was about 18% of the total sap flow. Rainfall was 507 mm in 2015, 359 mm in 2016, and 220 mm in 2017. Transpiration was 53%, 30%, and 75%, respectively, of the rainfall in those years, and was affected by the distribution of the rainfall. The trees showed an immediate response to rainfall events, but also exploited the fractured bedrock. The transpiration and soil moisture levels over the three hydrologically contrasting years showed that P. brutia is well-adapted to semi-arid Mediterranean conditions.

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Rainfall pattern greatly affects water use by Mongolian Scots pine on a sandy soil, in a semi-arid climate

10.5194/bg-2017-69 ◽

2017 ◽

Author(s):

Hongzhong Dang ◽

Lizhen Zhang ◽

Wenbin Yang ◽

Jinchao Feng ◽

Hui Han ◽

...

Keyword(s):

Soil Moisture ◽

Water Use ◽

Sandy Soil ◽

Heavy Rainfall ◽

Rainfall Pattern ◽

Severe Drought ◽

Sap Flux ◽

Sap Flux Density ◽

Tree Water Use ◽

Moderate Drought

Abstract. We report new information on tree water use by Mongolian Scots pine (Pinus sylvestris var. mongolica) growing on a sandy soil, in a region characterised by an erratic rainfall pattern. Measurements were made over three successive years of contrasting annual rainfall – a wet year (2013), a dry year (2014), and a second dry year (2015). The result was the development of worsening levels of drought year by year. Over the three years, sap flux density (Js) was measured at individual tree level in up to 25 trees. The sap flux density values were up-scaled to estimate tree water use at plot level (Ts). Our measurements follow forest plot response to increasing levels of drought which developed over a three-year period as soil moisture conditions gradually worsened from wet, to moderate-drought, to severe-drought, to extreme-drought, in response to the dynamics of a variable rainfall pattern. Values of Ts did not exceed 3.03 mm day−1 (2013), 1.75 mm day−1 (2014) and 1.59 mm day−1 (2015) during the three growing seasons. Total annual stand transpiration over the same three years declined progressively from 290 mm (2013), to 182 mm (2014) and to 175 mm (2015). Satisfactory power-function relationships (R2 = 0.64) between daily Ts and the product of ET0 and the relative extractable soil water (REW) were found. This study helps elucidate the interplay between the effects of the atmosphere and soil moisture on tree water use. Tree water use responded to drought, with daily Ts values decreasing by 5–46 % in response to moderate drought, by 48–62 % in response to severe drought and by 65 % in response to extreme drought. Upon release of moderate drought by heavy rainfall in 2013, daily Ts recovered completely. However, under the severe and extreme droughts in the subsequent dry years, recovery of Ts following heavy rainfall was incomplete (57–58 %). Our results highlight the negative effects of water stress on the growth of mature forest trees, in a sandy soil, in a climate characterised by large intra- and inter-annual variances in rainfall. When the erratic rainfall and sandy soil were also coupled with a declining groundwater table, the result was tree water use fluctuated widely over quite short time scales (months or weeks). Overall, our findings account for the observed premature degradation of these MP plantations in terms of an eco-hydrological perspective.

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Mediterranean cork oak woodlands and global changes: Synergistic and negative effects of recurrent droughts and shrub encroachment

10.5194/egusphere-egu2020-4901 ◽

2020 ◽

Author(s):

Simon Haberstroh ◽

Maria C. Caldeira ◽

Raquel Lobo-do-Vale ◽

Joana Martins ◽

Maren Dubbert ◽

...

Keyword(s):

Soil Water ◽

Flux Density ◽

Synergistic Effects ◽

Shrub Encroachment ◽

Cork Oak ◽

Extreme Drought ◽

Sap Flux ◽

Negative Effects ◽

Sap Flux Density ◽

Species Specific

Mediterranean type ecosystems such as cork oak (Quercus suber) woodlands are currently threatened by extreme drought events and shrub encroachment in the Iberian Peninsula. Recently, the frequency of extreme droughts has increased with negative effects on many ecosystems. Decreasing soil water availability reduces growth and fitness of trees, and may eventually induce tree mortality. Shrub encroachment may further increase the competition for soil water, impacting tree vulnerability and resilience negatively. Yet, the synergistic effects of extreme droughts and shrub encroachment on ecosystems have rarely been investigated.We established a precipitation manipulation and shrub encroachment experiment in a cork oak stand to study the combined effects of the two environmental pressures. The cork oak woodland is located in Southeast Portugal and partially invaded by the native shrub gum rockrose (Cistus ladanifer). In December 2017, we installed rainout shelters (30 to 45% of precipitation reduction) in replicated cork oak stands invaded and uninvaded by gum rockrose, complemented by control plots with natural precipitation. In each treatment, the trees (n = 9) and shrubs (n = 9) were measured for water and carbon fluxes to reveal species-specific responses and competition effects under recurrent extreme drought.The hydrological year 2018 was characterised by above-average precipitation mainly caused by large spring rainfall events. Probably due to sufficient water supply, no clear treatment effects were evident. For example, minimum leaf water potentials (&#936;PD) of the cork oak trees did not drop below &#8722;1.5 &#177; 0.1 MPa and maximum sap flux density was 2.1 &#177; 0.2 m3 m&#8722;2 day&#8722;1. Minimum &#936;PD of the shrubs was three times lower (&#8722;3.5 &#177; 0.1 MPa) and maximum sap flux density over four-fold higher (8.8 &#177; 0.8 m3 m&#8722;2 day&#8722;1) than those of the trees, suggesting distinct species-specific behaviour. Reduced winter and spring precipitation, combined with a late onset of autumn rainfalls in 2019, led to a decrease in water input down to 66% (control) and 44% (drought) compared to the long-term average of 585 mm. In this dry year, negative synergistic effects of drought and shrub encroachment were expressed during the dry-down and drought period by a lower minimum &#936;PD and an average sap flux density reduced by 50% (0.4 &#177; 0.1 m3 m&#8722;2 day&#8722;1) of invaded trees exposed to the experimental drought, compared to control trees (0.8 &#177; 0.1 m3 m&#8722;2 day&#8722;1). In sum, this resulted in a reduction of sap flux densities of the cork oaks by 25% (invaded), 23% (drought) and 34% (drought and invaded) over the course of the hydrological year 2019. The ongoing investigations aim to further determine the stress tolerance and critical physiological thresholds for both species and the entire ecosystem.

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Ammonium Nitrate and Phosphoric Acid Increase 2,4,5-T Absorption by Tree Leaves

Weed Science ◽

10.1017/s0043174500079571 ◽

1970 ◽

Vol 18 (2) ◽

pp. 204-206 ◽

Cited By ~ 12

Author(s):

Homer A. Brady

Keyword(s):

Phosphoric Acid ◽

Ammonium Nitrate ◽

Pinus Taeda ◽

Loblolly Pine ◽

Acer Rubrum ◽

Liquidambar Styraciflua ◽

Red Maple ◽

Tree Leaves ◽

Post Oak ◽

Quercus Stellata

Addition of ammonium nitrate greatly increased the absorption of solutions of the isooctyl ester of (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T) by sweetgum (Liquidambar styraciflua L.), post oak (Quercus stellata Wangenh.), red maple (Acer rubrum L.), and loblolly pine (Pinus taeda L.) leaves. Phosphoric acid alone and mixed with ammonium nitrate caused less increase. Ammonium nitrate speeded translocation of the herbicide in post oak but not in the other species.

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Sap Flow Dynamics and Responses to Grazing and Seasonal Changes in Soil Moisture for Acacia Ancistroclada and Comberatum Molle in a Kenyan Savanna

10.21203/rs.3.rs-48464/v1 ◽

2020 ◽

Author(s):

Joseph Ondier ◽

Dennis Otieno ◽

Daniel Okach ◽

John Onyango

Keyword(s):

Soil Moisture ◽

Vapor Pressure ◽

Flux Density ◽

Sap Flow ◽

Seasonal Changes ◽

Vapor Pressure Deficit ◽

Livestock Grazing ◽

Sap Flux ◽

Sap Flux Density ◽

Rainfall Patterns

Abstract The Kenyan savanna, which is dominated by Acacia ancistroclada and Comberatum molle, has experienced notable changes in rainfall patterns and increased livestock grazing. A significant decrease in trees spread from 5 % to less than 1 % has been documented for the ecosystem and could be linked to the increased livestock grazing and changes in rainfall patterns, however, scientific evidence is lacking. We utilized sap flow to analyze the hydraulic responses of the prevailing trees to livestock grazing and seasonal changes in soil moisture. Environmental factors including precipitation, air temperature, soil moisture at - 0.3 m, and vapor pressure deficit were simultaneously measured. The results showed that the diurnal variation in sap flux density exhibited a single peak curve at around midday and correlated strongly with vapor pressure deficit and air temperature. Sap flux density was higher in the grazed (27.47 ± 8.65 g m-2s-1) than the fenced plots (20.17 ± 7.27 g m-2s-1). In all the plots, sap flux density followed seasonality in rainfall patterns, increasing and decreasing in wet and dry seasons respectively. The higher crown projected area was responsible for higher sap flow in the grazed plots. The diurnal variation in sap flux density showed that sap flow was coupled to the atmosphere with relatively low boundary layer resistance and the seasonal variation in sap flow was controlled by stomatal regulation. These findings point to the possibility that the dominant tree species in Lambwe are isohydric species. However, additional measurements need to be conducted on the eligibility of the species to confirm the conclusion.

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Specific responses of sap flux and leaf functional traits to simulated canopy and understory nitrogen additions in a deciduous broadleaf forest

Functional Plant Biology ◽

10.1071/fp18277 ◽

2019 ◽

Vol 46 (11) ◽

pp. 986 ◽

Cited By ~ 1

Author(s):

Liwei Zhu ◽

Yanting Hu ◽

Xiuhua Zhao ◽

Ping Zhao ◽

Lei Ouyang ◽

...

Keyword(s):

Functional Traits ◽

Xylem Sap ◽

Leaf Traits ◽

N Addition ◽

Sap Flux ◽

Sap Flux Density ◽

Leaf Functional Traits ◽

Species Specific ◽

Xylem Sap Flux ◽

N Additions

To investigate the effects of atmospheric nitrogen (N) deposition on water use characteristics and leaf traits of trees, we performed canopy (C50) and understory (U50) N additions as NH4NO3 of 50 kg N ha–1 year–1 in a deciduous broadleaf forest of central China. We measured xylem sap flux, crown area:sapwood area ratio (Ca:As), specific leaf area (SLA), mass-based leaf nitrogen content (Nmass) and leaf carbon isotope ratio (δ13C) of Liquidambar formosana Hance, Quercus acutissima Carruth. and Quercus variabilis Blume. Functional traits under different N addition treatments and their responses among tree species were compared and the relationship between xylem sap flux and leaf functional traits under N additions were explored. Results showed that under U50 sap-flux density of xylem significantly decreased for three tree species. But the effect of C50 on sap flux was species-specific. The decrease of sap-flux density with N additions might be caused by the increased Ca/As. δ13C remained constant among different N addition treatments. The responses of SLA and Nmass to N additions were species- and N addition approaches-specific. The correlation of xylem sap flux with leaf traits was not found. Our findings indicate that the effects of canopy N addition on xylem sap flux and leaf functional traits were species-specific and it is necessary to employ canopy N addition for exploring the real responses of forest ecosystems to climate changes in the future researches.

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Azimuthal variations of sap flux density within Japanese cypress xylem trunks and their effects on tree transpiration estimates

Journal of Forest Research ◽

10.1007/s10310-010-0202-0 ◽

2010 ◽

Vol 15 (6) ◽

pp. 398-403 ◽

Cited By ~ 28

Author(s):

Kenji Tsuruta ◽

Tomonori Kume ◽

Hikaru Komatsu ◽

Naoko Higashi ◽

Toshihiro Umebayashi ◽

...

Keyword(s):

Flux Density ◽

Sap Flux ◽

Sap Flux Density ◽

Japanese Cypress ◽

Tree Transpiration

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Transpiration rates of red maple (Acer rubrum L.) differ between management contexts in urban forests of Maryland, USA

Scientific Reports ◽

10.1038/s41598-021-01804-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sarah Ponte ◽

Nancy F. Sonti ◽

Tuana H. Phillips ◽

Mitchell A. Pavao-Zuckerman

Keyword(s):

Urban Forest ◽

Stormwater Runoff ◽

Acer Rubrum ◽

Urban Forests ◽

Urban Trees ◽

Environmental Drivers ◽

Sap Flux ◽

Red Maple ◽

Canopy Trees ◽

Closed Canopy

AbstractThe hydrological functioning of urban trees can reduce stormwater runoff, mitigate the risk of flood, and improve water quality in developed areas. Tree canopies intercept rainfall and return water to the atmosphere through transpiration, while roots increase infiltration and storage in the soil. Despite this, the amount of stormwater that trees remove through these functions in urban settings is not well characterized, limiting the use of urban forests as practical stormwater management strategies. To address this gap, we use ecohydrological approaches to assess the transpiration rates of urban trees in different management settings. Our research questions are: Do transpiration rates of trees of the same species vary among different management contexts? Do relationships between environmental drivers and transpiration change among management contexts? These management settings included single trees over turfgrass and a cluster of trees over turfgrass in Montgomery County, MD, and closed canopy forest with a leaf litter layer in Baltimore, MD. We used sap flux sensors installed in 18 mature red maple (Acer rubrum L.) trees to characterize transpiration rates during the growing season. We also measured soil volumetric water content, air temperature, relative humidity, and precipitation at each site. In agreement with our initial hypothesis, we found that single trees had nearly three times the daily sum of sap flux density (JS) of closed canopy trees. When averaged over the entire measurement period, JS was approximately 260, 195, and 91 g H2O cm−2 day−1 for single trees, cluster trees and closed canopy trees, respectively. Additionally, single trees were more responsive to VPD than closed canopy and cluster trees. These results provide a better understanding of the influence of management context on urban tree transpiration and can help to identify targets to better manage urban forest settings to reduce urban stormwater runoff.

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Comparison of water-use characteristics of tropical tree saplings with implications for forest restoration

Scientific Reports ◽

10.1038/s41598-021-81334-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tushar Andriyas ◽

Nisa Leksungnoen ◽

Pantana Tor-ngern

Keyword(s):

Soil Moisture ◽

Water Use ◽

Forest Restoration ◽

Early Stage ◽

Tree Canopy ◽

Canopy Conductance ◽

Modeling Framework ◽

Sap Flux Density ◽

Species Specific ◽

Moisture Conditions

AbstractTropical forests are experiencing reduced productivity and will need restoration with suitable species. Knowledge of species-specific responses to changing environments during early stage can help identify the appropriate species for sustainable planting. Hence, we investigated the variability in whole-tree canopy conductance and transpiration (Gt and EL) in potted saplings of common urban species in Thailand, viz., Pterocarpus indicus, Lagerstroemia speciosa, and Swietenia macrophylla, across wet and dry seasons in 2017–2018. Using a Bayesian modeling framework, Gt and EL were estimated from sap flux density, informed by the soil, atmospheric and tree measurements. Subsequently, we evaluated their variations with changing vapor pressure deficit (VPD) and soil moisture across timescales and season. We found that Gt and EL were higher and highly variable in L. speciosa across seasons than S. macrophylla and P. indicus. Our results implied that water-use in these species was sensitive to seasonal VPD. L. speciosa may be suitable under future climate variability, given its higher Gt and EL across atmospheric and soil moisture conditions. With their lower Gt and EL, P. indicus and S. macrophylla may photosynthesize throughout the year, maintaining their stomatal opening even under high VPD. These findings benefit reforestation and reclamation programs of degraded lands.

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Costs and Benefits of Implementing Sensor-controlled Irrigation in a Commercial Pot-in-Pot Container Nursery

HortTechnology ◽

10.21273/horttech.23.6.760 ◽

2013 ◽

Vol 23 (6) ◽

pp. 760-769 ◽

Cited By ~ 28

Author(s):

Bruk E. Belayneh ◽

John D. Lea-Cox ◽

Erik Lichtenberg

Keyword(s):

Soil Moisture ◽

Acer Rubrum ◽

Economic Benefits ◽

Irrigation Scheduling ◽

Payback Period ◽

Base Station ◽

Plant Production ◽

Wireless Sensor ◽

Red Maple ◽

Controlled Irrigation

Irrigation scheduling in ornamental plant production is complex due to the large number of species grown by individual growers and the need to consider plant, environment, and substrate conditions to make correct irrigation decisions on a daily or more frequent basis. The engineering team in our project has developed a smart wireless sensor node that is capable of integrating outputs from a range of soil moisture and environmental sensors to schedule irrigation events. In addition, an advanced monitoring and control software enables growers to manage irrigation based on set-point or model-based protocols, which are then independently executed by the nodes, enhancing or replacing human decision making. During 2012, we implemented a sensor-controlled vs. grower-controlled irrigation study at a pot-in-pot nursery in Tennessee. Sensor networks were installed in two separate production blocks of 3-year-old dogwood (Cornus florida ‘Cherokee Brave’) and 2-year-old red maple (Acer rubrum ‘Autumn Blaze’) trees grown in 15- and 30-gal containers, respectively. One row of trees in each block was irrigated based on the average reading of soil moisture sensors inserted in individual trees using micropulse irrigation, i.e., sensor controlled. Trees in the adjacent row and the rest of the block were independently irrigated by the grower using standard practices, i.e., grower controlled. Sensor volumetric water content (VWC) readings and irrigation volumes were logged by nodes on a 15-min basis and were relayed to a base station on the farm. For the study period between Mar. 2012 and Nov. 2012, average daily water applied by the grower-controlled irrigation to the dogwood block was 0.92 gal/tree, compared with 0.34 gal/tree applied using sensor-controlled irrigation; for red maple, these values were 1.72 gal/tree and 1.13 gal/tree, respectively. No significant differences in tree caliper or quality were noted between the two irrigation treatments in either species over the year. The cost of water for this particular operation was negligible consisting only of pumping costs, as water is drawn from a perennial stream with excellent water quality. Consequently, a conservative return on investment for a wireless sensor network capable of covering the entire operation was 37.5%, corresponding to a payback period of 2.7 years, associated almost entirely from a reduction in irrigation management time. Pricing in a nominal cost for water of $326 per acre-foot ($1 per 1000 gal) increased annualized net savings 9-fold, reducing the payback period to less than 4 months. This analysis did not factor in additional economic benefits such as reductions in production time, losses due to disease, or increased plant quality, which have been associated with the use of sensor-based irrigation control in other studies.

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