Responses of plant water use to a severe summer drought for two subtropical tree species in the central southern China

Luo, Zidong; Guan, Huade; Zhang, Cicheng; Liu, Na; Li, Guang

doi:10.1016/j.ejrh.2016.08.001

Cited by 19 publications

(20 citation statements)

References 31 publications

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“…Mean annual air temperature is about 17.4C, and mean annual precipitation is 1447 mm (mainly distributes from March to June). Resulting from different air mass influences in the summer monsoon season, precipitation distributes unevenly between months, often leading to low precipitation in midsummer (Luo et al, 2016). Soils at this site are silty loam, with clay, silt and sand content about 20.1%, 75.7% and 4.2%, respectively.…”

Section: Study Sitementioning

confidence: 95%

Examination of the ecohydrological separation hypothesis in a humid subtropical area: Comparison of three methods

Luo

Guan

Zhang

et al. 2019

Journal of Hydrology

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The ecohydrological separation between soil water sources for plant water uptake and groundwater recharge has been recently examined in various climate zones primarily based on isotopic composition of water. The existence of the ecohydrological separation has profound implications for mechanistic ecohydrological modeling and water resource management. However, it is still unclear when and where the ecohydrological separation occurs, especially in humid regions. In this study, high frequency sampling of precipitation, bulk soil water, groundwater and twig xylem water for hydrogen and oxygen isotope composition measurement was conducted in a humid subtropical site in the central southern China from March 2017 to April 2018. We examined evidence of the ecohydrological separation with three methods (dual-isotope space, line-conditioned excess (lc-excess), and the piecewise isotope balance (PIB) method). The results show that the isotope compositions of plant xylem and bulk soil water are not distinguishable from those of precipitation water on the dual-isotope space due to a weak evaporation effect at the study site, indicating that there is no evidence of the ecohydrological separation.However, the other two methods support the ecohydrological separation in this humid area, with the results from the PIB method revealing more temporal details. The present study suggests that the ecohydrological separation can happen in subtropical humid climate. It is more likely to occur in spring and winter at the study site when plant-accessible water pool has been replenished by antecedent precipitation, while ecohydrological connection seems to occur during winter snowmelt. With the limitations of three methods, the caution should be taken when only one method is 3 applied in examining the ecohydrological separation in such an environment. Highlights Two commonly used methods for assessing the ecohydrological separation show inconsistent results. A new method based on root zone isotope mass balance supports the ecohydrological separation at the studied humid site. The ecohydrological connection occurs during snowmelt at the site.

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Section: Study Sitementioning

confidence: 95%

Examination of the ecohydrological separation hypothesis in a humid subtropical area: Comparison of three methods

Luo

Guan

Zhang

et al. 2019

Journal of Hydrology

Self Cite

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“…Unfortunately, datasets of Ψ min are typically patchy because of the laborious onsite measurement techniques that are involved. Continuous remote monitoring of Ψ x is now becoming possible because of the development of a new generation of wireless sensors that can be deployed at remote sites 129,130 . This will enable a much higher resolution of Ψ min , the true maximum level of stress that trees are exposed to during natural droughts, and how long they spend at a given Ψ x .…”

Section: Review Researchmentioning

confidence: 99%

Triggers of tree mortality under drought

Choat

Brodribb

Brodersen

et al. 2018

Nature

1,223

933

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Severe droughts have caused widespread tree mortality across many forest biomes with profound effects on the function of ecosystems and carbon balance. Climate change is expected to intensify regional-scale droughts, focusing attention on the physiological basis of drought-induced tree mortality. Recent work has shown that catastrophic failure of the plant hydraulic system is a principal mechanism involved in extensive crown death and tree mortality during drought, but the multi-dimensional response of trees to desiccation is complex. Here we focus on the current understanding of tree hydraulic performance under drought, the identification of physiological thresholds that precipitate mortality and the mechanisms of recovery after drought. Building on this, we discuss the potential application of hydraulic thresholds to process-based models that predict mortality.

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“…sapwood depth, tree size, phenology) appear to outweigh taxonomic affiliation, as indicated by considerable convergence in sap flow among phylogenetically diverse, but morphologically similar, species in tropical systems (Meinzer et al ., ; O'Brien et al ., ; McJannet et al ., ; Kunert et al ., ; Moore et al ., ). Recent work on sap flow in subtropical and tropical biomes includes the assessment of responses to drought (Luo et al ., ), environmental factors (Eller et al ., ; Aparecido et al ., ) and seasonal variability (Kunert et al ., ; Schwendenmann et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Plant water use responses along secondary forest succession during the 2015–2016 El Niño drought in Panama

2018

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Tropical forests are increasingly being subjected to hotter, drier conditions as a result of global climate change. The effects of drought on forests along successional gradients remain poorly understood. We took advantage of the 2015-2016 El Niño event to test for differences in drought response along a successional gradient by measuring the sap flow in 76 trees, representing 42 different species, in 8-, 25- and 80-yr-old secondary forests in the 15-km 'Agua Salud Project' study area, located in central Panama. Average sap velocities and sapwood-specific hydraulic conductivities were highest in the youngest forest. During the dry season drought, sap velocities increased significantly in the 80-yr-old forest as a result of higher evaporative demand, but not in younger forests. The main drivers of transpiration shifted from radiation to vapor pressure deficit with progressing forest succession. Soil volumetric water content was a limiting factor only in the youngest forest during the dry season, probably as a result of less root exploration in the soil. Trees in early-successional forests displayed stronger signs of regulatory responses to the 2015-2016 El Niño drought, and the limiting physiological processes for transpiration shifted from operating at the plant-soil interface to the plant-atmosphere interface with progressing forest succession.

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Responses of plant water use to a severe summer drought for two subtropical tree species in the central southern China

Cited by 19 publications

References 31 publications

Examination of the ecohydrological separation hypothesis in a humid subtropical area: Comparison of three methods

Examination of the ecohydrological separation hypothesis in a humid subtropical area: Comparison of three methods

Triggers of tree mortality under drought

Plant water use responses along secondary forest succession during the 2015–2016 El Niño drought in Panama

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