Drought Superimposes the Positive Effect of Silver Fir on Water Relations of European Beech in Mature Forest Stands

Research Highlights: Investigations of evapotranspiration in a mature mixed beech-fir forest stand do not indicate higher resilience towards intensified drying-wetting cycles as compared with pure beech stands. Background and Objectives: Forest management seeks to implement adaptive measures, for example, the introduction of more drought resistant species into prevailing monospecific stands to minimize forest mortality and monetary losses. In Central Europe this includes the introduction of native silver fir (Abies alba) into monospecific beech (Fagus sylvatica) stands. In order to determine, if the introduction of fir would improve the resilience against drier conditions, this study investigates water relations of a mature pure beech and a mature mixed beech-fir stand under natural as well as reduced water availability. Materials and Methods: Sap flow rates and densities were measured in two consecutive years using the heat ratio method and scaled using stand inventory data and modeling. Results: Transpiration rates estimated from sap flow were significantly higher for beech trees as compared with silver fir which was attributed to the more anisohydric water-use strategy of the beech trees. We estimate that stand evapotranspiration was slightly higher for mixed stands due to higher interception losses from the mixed stand during times of above average water supply. When precipitation was restricted, beech was not able to support its transpiration demands, and therefore there was reduced sap flow rates in the mixed, as well as in the pure stand, whereas transpiration of fir was largely unaffected, likely due to its more isohydric behavior toward water use and access to moister soil layers. Thus, we found the rates of evapotranspiration in the mixed beech-fir stand to be smaller during times with no precipitation as compared with the pure beech stand, which was accountable to the severely reduced transpiration of beech in the mixed stand. Conclusions: We conclude that smaller evapotranspiration rates in the mixed beech-fir stand might not be the result of increased water use efficiency but rather caused by restricted hydraulic conductivity of the root system of beech, making mixed beech-fir stands at this site less resilient towards drought.

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Water-use dynamics of an alien-invaded riparian forest within the Mediterranean climate zone of the Western Cape, South Africa

Hydrology and Earth System Sciences ◽

10.5194/hess-21-4551-2017 ◽

2017 ◽

Vol 21 (9) ◽

pp. 4551-4562 ◽

Cited By ~ 3

Author(s):

Bruce C. Scott-Shaw ◽

Colin S. Everson ◽

Alistair D. Clulow

Keyword(s):

South Africa ◽

Water Use ◽

Sap Flow ◽

Riparian Forest ◽

Riparian Forests ◽

Ratio Method ◽

Natural State ◽

Indigenous Species ◽

Western Cape ◽

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 program, to justify alien tree removal and implement rehabilitation unless hydrological benefits are known. Consequently, water use within a riparian forest along the Buffeljags River in the Western Cape of South Africa was monitored over a 3-year period. The site consisted of an indigenous stand of Western Cape afrotemperate forest adjacent to a large stand of introduced Acacia mearnsii. The heat ratio method of the heat pulse velocity sap flow technique was used to measure the sap flow of a selection of indigenous species in the indigenous stand, a selection of A. mearnsii trees in the alien stand and two clusters of indigenous species within the alien stand. The indigenous trees in the alien stand at Buffeljags River showed significant intraspecific differences in the daily sap flow rates varying from 15 to 32 L day−1 in summer (sap flow being directly proportional to tree size). In winter (June), this was reduced to only 7 L day−1 when limited energy was available to drive the transpiration process. The water use in the A. mearnsii trees showed peaks in transpiration during the months of March 2012, September 2012 and February 2013. These periods had high average temperatures, rainfall and high daily vapor pressure deficits (VPDs – average of 1.26 kPa). The average daily sap flow ranged from 25 to 35 L in summer and approximately 10 L in the winter. The combined accumulated daily sap flow per year for the three Vepris lanceolata and three A. mearnsii trees was 5700 and 9200 L, respectively, clearly demonstrating the higher water use of the introduced Acacia trees during the winter months. After spatially upscaling the findings, it was concluded that, annually, the alien stand used nearly 6 times more water per unit area than the indigenous stand (585 mm a−1 compared to 101 mm a−1). This finding indicates that there would be a gain in groundwater recharge and/or streamflow if the alien species are removed from riparian forests and rehabilitated back to their natural state.

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Determination of the water use of two pairs of soybean isolines differing in stomatal frequency using a heat balance stem flow gauge

Canadian Journal of Plant Science ◽

10.4141/cjps95-016 ◽

1995 ◽

Vol 75 (1) ◽

pp. 99-103 ◽

Cited By ~ 2

Author(s):

C. S. Tan ◽

B. R. Buttery

Keyword(s):

Soil Moisture ◽

Water Use ◽

Heat Balance ◽

Sap Flow ◽

Stomatal Frequency ◽

Flow Rates ◽

High Soil Moisture ◽

Stem Flow ◽

Glycine Max L

Using heat-balance stem flow gauges, we were able to measure directly and continuously the sap flow rates in two pairs of soybean [Glycine max (L.) Merr.] isolines differing in stomatal frequency. Plants with high stomatal frequency transpired significantly more water than the low stomatal frequency plants at high soil moisture levels. Under low soil moisture levels, the water use rate decreased greatly for the high stomatal frequency plants. Plants with low stomatal frequency were able to maintain greater sap flow rates than those with high stomatal frequency. Higher leaf temperatures associated with the low stomatal frequency plants were likely due to lower transpiration rates which reduced evaporative cooling especially under well-watered conditions. Key words:Glycine max (L.) Merr., transpiration, water deficits

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Stand-Level Transpiration Increases after Eastern Redcedar (Juniperus virginiana L.) Encroachment into the Midstory of Oak Forests

Forests ◽

10.3390/f11090901 ◽

2020 ◽

Vol 11 (9) ◽

pp. 901 ◽

Cited By ~ 2

Author(s):

Patricia R. Torquato ◽

Rodney E. Will ◽

Bo Zhang ◽

Chris B. Zou

Keyword(s):

Water Use ◽

Sap Flow ◽

Structural Equation ◽

Mixed Forest ◽

Flow Density ◽

Juniperus Virginiana ◽

Cross Timbers ◽

Eastern Redcedar ◽

Mixed Species ◽

Mixed Stands

Eastern redcedar (Juniperus virginiana L., redcedar) encroachment is transitioning the oak-dominated Cross-Timbers of the southern Great Plain of the USA into mixed-species forests. However, it remains unknown how the re-assemblage of tree species in a semiarid to sub-humid climate affects species-specific water use and competition, and ultimately the ecosystem-level water budget. We selected three sites representative of oak, redcedar, and oak and redcedar mixed stands with a similar total basal area (BA) in a Cross-Timbers forest near Stillwater, Oklahoma. Sap flow sensors were installed in a subset of trees in each stand representing the distribution of diameter at breast height (DBH). Sap flow of each selected tree was continuously monitored over a period of 20 months, encompassing two growing seasons between May 2017 and December 2018. Results showed that the mean sap flow density (Sd) of redcedar was usually higher than post oaks (Quercus stellata Wangenh.). A structural equation model showed a significant correlation between Sd and shallow soil moisture for redcedar but not for post oak. At the stand level, the annual water use of the mixed species stand was greater than the redcedar or oak stand of similar total BA. The transition of oak-dominated Cross-Timbers to redcedar and oak mixed forest will increase stand-level transpiration, potentially reducing the water available for runoff or recharge to groundwater.

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

Agronomía Colombiana ◽

10.15446/agron.colomb.v34n2.55649 ◽

2016 ◽

Vol 34 (2) ◽

pp. 172-178 ◽

Cited By ~ 4

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.

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Nitrogen Nutrition of European Beech Is Maintained at Sufficient Water Supply in Mixed Beech-Fir Stands

Forests ◽

10.3390/f9120733 ◽

2018 ◽

Vol 9 (12) ◽

pp. 733 ◽

Cited By ~ 6

Author(s):

Ruth-Kristina Magh ◽

Fengli Yang ◽

Stephanie Rehschuh ◽

Martin Burger ◽

Michael Dannenmann ◽

...

Keyword(s):

Water Supply ◽

Water Relations ◽

European Beech ◽

Soil Parameters ◽

Silver Fir ◽

Soil N ◽

Uptake Capacity ◽

Mixed Stands ◽

Total N ◽

N Nutrition

Research highlights: Interaction effects of coniferous on deciduous species have been investigated before the background of climate change. Background and objectives: The cultivation of European beech (Fagus sylvatica L.) in mixed stands has currently received attention, since the future performance of beech in mid-European forest monocultures in a changing climate is under debate. We investigated water relations and nitrogen (N) nutrition of beech in monocultures and mixed with silver-fir (Abies alba Mill.) in the Black Forest at different environmental conditions, and in the Croatian Velebit at the southern distribution limit of beech, over a seasonal course at sufficient water availability. Material and methods: Water relations were analyzed via δ13C signatures, as integrative measures of water supply assuming that photosynthesis processes were not impaired. N nutrition was characterized by N partitioning between soluble N fractions and structural N. Results: In the relatively wet year 2016, water relations of beech leaves, fir needles and roots differed by season, but generally not between beech monocultures and mixed cultivation. At all sites, previous and current year fir needles revealed significantly lower total N contents over the entire season than beech leaves. Fir fine roots exhibited higher or similar amounts of total N compared to needles. Correlation analysis revealed a strong relationship of leaf and root δ13C signatures with soil parameters at the mixed beech stands, but not at pure beech stands. While glutamine (Gln) uptake capacity of beech roots was strongly related to soil N in the monoculture beech stands, arginine (Arg) uptake capacities of beech roots were strongly related to soil N in mixed stands. Conclusions: Leaf N contents indicated a facilitative effect of silver-fir on beech on sites where soil total N concentrations where low, but an indication of competition effect where it was high. This improvement could be partially attributed to protein contents, but not to differences in uptake capacity of an individual N source. From these results it is concluded that despite similar performance of beech trees at the three field sites investigated, the association with silver-fir mediated interactive effects between species association, climate and soil parameters even at sufficient water supply.

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From tree to stand: Scaling relationships of water uptake and climate in a reclaimed boreal mixedwood stand.

10.5194/egusphere-egu2020-22489 ◽

2020 ◽

Author(s):

Morgane Merlin ◽

Simon M. Landhäusser ◽

Sean K. Carey

Keyword(s):

Water Uptake ◽

Populus Tremuloides ◽

Sap Flow ◽

White Spruce ◽

Ratio Method ◽

Water Fluxes ◽

Trembling Aspen ◽

Individual Tree ◽

Flow Rates ◽

The Relationship

Soil water availability is a key factor in determining tree&#8217;s transpiration and sap flow rates, and varies with topography and soil depth. Reclaimed landscapes provide us with the unique opportunity to address the effects of those two variables independently on trees&#8217; water uptake, and their relationship to climatic variation. We explored the relationship between individual tree water uptake and atmospheric variables for trembling aspen (Populus tremuloides) and white spruce (Picea glauca), and assessed how this relationship changed across different hillslope positions and rooting space. Growing season (May to September) sap and transpiration fluxes were monitored using heat ratio method sap flow sensors on trembling aspen and white spruce trees in 2014 and 2015 on a reclaimed hillslope in northern Alberta, Canada, with two different soil cover depths providing different rooting spaces. Both species&#8217; sap flow rates and transpiration rates were strongly correlated to climatic variables such as vapor pressure deficit, precipitation events, air temperature, with slight differences in the relationship between topographical positions and soil depths. Site-level atmospheric water fluxes were obtained through eddy covariance measurements at the top of the hillslope. This allowed for a direct linkage of individual tree water uptake measurement to water flux measurements taken at the landscape-level. Understanding how distinct rooting and physiological characteristics of tree species and their growing conditions can be extrapolated to different scales, is crucial to our understanding of both atmospheric and edaphic water fluxes.

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Responses of petiole sap flow to light and vapor pressure deficit in the tropical tree Tabebuia rosea (Bignoniaceae)

10.7287/peerj.preprints.1017 ◽

2015 ◽

Author(s):

Adam Roddy ◽

Klaus Winter ◽

Todd Dawson

Keyword(s):

Vapor Pressure ◽

Sap Flow ◽

Vapor Pressure Deficit ◽

Water Flux ◽

Tropical Tree ◽

Environmental Drivers ◽

Ratio Method ◽

Flow Rates ◽

Leaf Level ◽

Tabebuia Rosea

Continuous measurements of sap flow have been widely used to estimate water flux through tree stems and branches. However, stem-level measurements lack the resolution necessary for accurately determining fine-scale, leaf-level responses to environmental variables. We used the heat ratio method to measure sap flow rates through leaf petioles and leaflet petiolules of saplings of the tropical tree Tabebuia rosea (Bignoniaceae) to determine how leaf and leaflet sap flow responds to variation in photosynthetically active radiation (PAR) and vapor pressure deficit (VPD). In the morning sap flow rates to east-facing leaves increased 26 minutes before adjacent west-facing leaves. Integrated daily sap flow was negatively correlated with daily mean VPD, and sap flow declined when VPD exceeded 2.2 kPa whether this occurred in the morning or afternoon, consistent with a feedforward response to humidity. Indeed, changes in VPD lagged behind changes in sap flow. In contrast, changes in PAR often preceded changes in sap flow. The sap flow-VPD relationship was characterized by two distinct patterns of hysteresis, while the sap flow-PAR relationship displayed three types of hysteresis, and the type of VPD hysteresis that occurred on a given day was correlated with the type of PAR hysteresis occurring on that day. These patterns highlight how multiple environmental drivers interact to control leaf sap flux and that the development of sap flow sensors capable of measuring individual leaves could drastically influence the amount of data recordable for these structures.

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

Functional Plant Biology ◽

10.1071/fp13156 ◽

2014 ◽

Vol 41 (8) ◽

pp. 874 ◽

Cited By ~ 13

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.

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

Hydrology and Earth System Sciences ◽

10.5194/hess-23-1553-2019 ◽

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.

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Tree biomass allometry during the early growth of Norway spruce (Picea abies) varies between pure stands and mixtures with European beech (Fagus sylvatica)

Canadian Journal of Forest Research ◽

10.1139/cjfr-2017-0177 ◽

2018 ◽

Vol 48 (1) ◽

pp. 77-84 ◽

Cited By ~ 6

Author(s):

Ioan Dutcă ◽

Richard Mather ◽

Florin Ioraş

Keyword(s):

Picea Abies ◽

Norway Spruce ◽

Fagus Sylvatica ◽

Aboveground Biomass ◽

European Beech ◽

Mixed Stand ◽

Pure Stand ◽

Tree Biomass ◽

Mixed Stands ◽

Individual Tree

In this paper, we report an investigation of how forest stand mixture may affect biomass allometric relationships in Norway spruce (Picea abies (L.) Karst.). Analysis of aboveground biomass data was conducted for 50 trees: 25 sample trees from a pure Norway spruce stand and 25 from a mixed stand of Norway spruce with European beech (Fagus sylvatica L.). ANCOVA results demonstrated that individual-tree biomass allometry of the pure stand significantly differed from that of the mixed stand. Allometric characteristics depended on the biomass component recorded and the type of biomass predictor used. When predicted by diameter at breast height and (or) height, the total aboveground biomass of mixed-stand trees was significantly less than that for pure-stand trees. This “apparent” lower aboveground biomass was attributed to the lower branch and needle biomass proportions of trees growing in mixed stand. The findings indicate that caution should be exercised when applying biomass allometric models developed from pure stands to predict tree biomass in mixed stands (and vice versa), as such data treatment may introduce significant bias.

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