Throughfall drop sizes suggest canopy flowpaths vary by phenophase

Nanko, Kazuki; Keim, Richard F.; Hudson, Sean A.; Levia, Delphis F.

doi:10.1016/j.jhydrol.2022.128144

Cited by 13 publications

(21 citation statements)

References 57 publications

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“…Nanko et al. (2022) developed their classifications based on drop size distribution and its timing. They inferred flow paths and residence times in the canopy from this drop data.…”

Section: Discussionmentioning

confidence: 99%

“…Nanko et al. (2022) recorded structurally mediated woody surface drip points in a humid subtropical climate with American beech, yellow poplar red maple and oak, indicating that they are not unique to the Banksia woodland. Additionally, authors have observed this process on fig trees ( Ficus macrophylla ) in Western Australia.…”

Section: Discussionmentioning

confidence: 99%

“…Nanko et al (2022) distinguished structurally mediated woody surface drip points that were fixed in space from occasional or transient woody surface drip points that moved. The focus of this study on Nanko et al (2022)'s "structurally mediated woody surface drip points." As we do not measure drop size, we shall identify drip points based on a positively outlying quantity of throughfall compared to rainfall (defined in Section 2.3).…”

Section: Introductionmentioning

confidence: 99%

“…Rivulets that detach before reaching the stem form a pour point, and rivulets reaching the stem form stemflow (Herwitz, 1987). This is discussed from the perspective of drop sizes by Nanko et al (2022).…”

Section: Introductionmentioning

confidence: 99%

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Introducing Pour Points: Characteristics and Hydrological Significance of a Rainfall‐Concentrating Mechanism in a Water‐Limited Woodland Ecosystem

Kunadi,

Lardner,

Silberstein

et al. 2024

Water Resources Research

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The interception of rainfall by plant canopies alters the depth and spatial distribution of water arriving at the soil surface, and thus the location, volume, and depth of infiltration. Mechanisms like stemflow are known to concentrate rainfall and route it deep into the soil, yet other mechanisms of flow concentration are poorly understood. This study characterizes pour points, formed by the detachment of water flowing under a branch, using a combination of field observations in Western Australian banksia woodlands and rainfall simulation experiments on Banksia menziesii branches. We aim to establish the hydrological significance of pour points in a water‐limited woodland ecosystem, along with the features of the canopy structure and rainfall that influence pour point formation and fluxes. Pour points were common in the woodland and could be identified by visually inspecting trees. Throughfall depths at pour points were up to 15 times greater than rainfall and generally comparable to or greater than stemflow. Soil water content beneath pour points was greater than in adjacent controls, with 20%–30% of the seasonal rainfall volume infiltrated into the top 1 m of soil beneath pour points, compared to 5% in controls. Rainfall simulations showed that pour points amplified the spatial heterogeneity of throughfall, violating assumptions used to close the water balance. The simulation experiments demonstrated that pour point fluxes depend on the interaction of branch angle and foliation for a given branch architecture. Pour points can play a significant part in the water balance, depending on their density and rainfall concentration ability.

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“…Nanko et al. (2022) developed their classifications based on drop size distribution and its timing. They inferred flow paths and residence times in the canopy from this drop data.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Introducing Pour Points: Characteristics and Hydrological Significance of a Rainfall‐Concentrating Mechanism in a Water‐Limited Woodland Ecosystem

Kunadi,

Lardner,

Silberstein

et al. 2024

Water Resources Research

View full text Add to dashboard Cite

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“…While some raindrops penetrate through the canopy to the ground without interacting with vegetation surfaces, a large proportion of raindrops of various sizes impact vegetative surfaces in the canopy (Herwitz, 1987; Roth‐Nebelsick et al, 2022). Upon impact, raindrops shatter on vegetative surfaces producing multiple, smaller residual drops, and these residual drops continue to fall to the ground or impact additional vegetative surfaces below before reaching the ground (Levia et al, 2019; Nanko et al, 2022; Papierowska et al, 2019). Additionally, a proportion of the smaller residual drops produced after raindrops shatter on vegetative surfaces can adhere to leaf surfaces contributing to the leaf surface storage (Lenz et al, 2022; Wohlfahrt et al, 2006; Xiong et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Progression toward maximum leaf surface storage during the rainfall interception process

Holder,

Lauderbaugh

2023

Hydrological Processes

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During rainfall events, leaves in the canopy absorb kinetic energy from falling raindrops causing the leaves to vibrate after each individual drop impact. Additionally, intercepted water gradually increases on foliar surfaces adding greater mass exerted on each leaf. This accumulated mass of water increases the leaf inclination angle and may enable the drainage of water from the leaf surface as the water drop retention angle is surpassed. This study explored the dynamic process of leaf vibration and changes in steady‐state leaf inclination angles after raindrop impact for three species (Acer saccharinum, Quercus gambelii, and Ulmus pumila) and with four different drop sizes. An incremental increase in steady‐state leaf inclination angle was measured from processing single frames of videos as each additional raindrop impacted leaf surfaces. In general, larger drops increased leaf inclination angles to a larger degree than the smaller drops. As maximum leaf surface storage or the water drop retention angle was approached, water drained from leaf surface causing an abrupt rebound of the leaf inclination angle. The maximum changes in steady‐state leaf inclination angle before rebound (LIAmax) and the number of drops needed for leaf inclination angle rebound were significantly correlated with the initial leaf inclination angle (LIAi) for experiments with A. saccharinum and U. pumila, but not for the experiments with Q. gambelii. No significant correlations were found between LIAmax and any leaf trait (i.e., leaf area, leaf mass, petiole length, petiole diameter, leaf hydrophobicity, and water drop retention) for A. saccharinum and U. pumila; however, a significant negative correlation was found for Q. gambelii between maximum changes in leaf inclination angle and petiole diameter. Of the leaf characteristics examined, leaf surface storage is most influenced by LIAi before drop impact.

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Idealized branch sections and hydrodynamic analysis characterize rainfall partitioning

Puri,

Kunadi,

Pfefferle

et al. 2024

Hydrological Processes

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Water flow on plant canopies determines the partitioning of intercepted rainfall between stemflow and throughflow, yet understanding of these flow processes remains minimally developed. Plant canopies may concentrate intercepted water into rivulets that flow beneath branches. If the rivulets remain attached to branches until they encounter the main tree trunk, they form stemflow. If the rivulets detach from branches, however, they form ‘pour points’, regions of concentrated throughfall. Here, rivulet flow below uniform cylinders was studied experimentally. Experimental observations were interpreted using hydrodynamic theory to predict the likelihood of a rivulet detaching based on a critical rivulet height (). Predictions of rivulet detachment were explored for a simplified case where water is introduced at known flow rates at a discrete point above a uniform, cylindrical ‘branch’. Where the branch was straight, the percentage of trials forming a rivulet, or the rivulet formation rate, increased with increasing branch inclination angle to the horizontal axis. Rivulet formation rates did not vary with flow rate. However, the volume of water collected at the end of the branch, analogous to stemflow, decreased with a higher flow rates due to the formation of flow instabilities. Rivulets forming on straight branches did not detach. Instead, the rivulet stream accelerated and reduced in height as it flowed along the cylinder. Rivulets formed on curved branches detached only when the branch axis after the curve approached the horizontal. Future theoretical and experimental studies can extend this work to improve understanding of more complex surfaces and branch architectures to mechanistically understand canopy interception.

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Throughfall drop sizes suggest canopy flowpaths vary by phenophase

Cited by 13 publications

References 57 publications

Introducing Pour Points: Characteristics and Hydrological Significance of a Rainfall‐Concentrating Mechanism in a Water‐Limited Woodland Ecosystem

Introducing Pour Points: Characteristics and Hydrological Significance of a Rainfall‐Concentrating Mechanism in a Water‐Limited Woodland Ecosystem

Progression toward maximum leaf surface storage during the rainfall interception process

Idealized branch sections and hydrodynamic analysis characterize rainfall partitioning

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