John Toland Van Stan- Ph.D.
- Associate Professor at Cleveland State University
John Toland Van Stan
- Ph.D.
- Associate Professor at Cleveland State University
About
176
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Introduction
My research seeks to enhance our understanding of the interface between hydrological processes and vegetated ecosystem functioning, as this is critical to the advancement of natural resource & watershed management.
You can find news and updates on my lab's twitter account: @Prof_Van_Stan.
Current institution
Additional affiliations
July 2017 - July 2021
August 2006 - May 2012
August 2012 - July 2017
Publications
Publications (176)
In this comic, a plant-loving tardigrade gives us a tour of their tree canopy neighborhood in the southeastern US. This tour focuses on the epiphytes (plants that live on the canopy) and tells stories about water-related challenges that plants-on-plants face when living "life on the limb." It also discusses the ecoservices of epiphytes and how clim...
As watersheds are complex systems that are difficult to directly study, the streams that drain them are often sampled to search for watershed “signals.” These signals include the presence and/or abundance of isotopes, types of sediment, organisms (including pathogens), chemical compounds associated with ephemeral biogeochemical processes or anthrop...
Nonvascular photoautotrophs (NVP), including bryophytes, lichens, terrestrial algae, and cyanobacteria, are increasingly recognized as being essential to ecosystem functioning in many regions of the world. Current research suggests that climate change may pose a substantial threat to NVP, but the extent to which this will affect the associated ecos...
Mistletoes have a global distribution and are the largest group of parasitic plants living within the canopies of woody plants. In European forests, Viscum album L. ssp. album (common mistletoe) is a common sight and, despite being considered a pest, can play beneficial roles in the ecosystem. However, mistletoe infections are becoming more severe...
In press at Forest Ecology & Management.
Rainfall-forest interactions significantly impacts hydrological, ecological, and societal systems by altering rain-water supply to the surface. Canopy surfaces' retention, evaporation, and redistribution of rain affect all storm-related hydrological processes. Arboreal epiphytes, plants that live on forest canopies, can store and evaporate substant...
Precipitation channelled down tree stems (stemflow) or into drip points of ‘throughfall’ beneath trees results in spatially concentrated inputs of water and chemicals to the ground. Currently, these flows are poorly characterised due to uncertainties about which branches redirect rainfall to stemflow or throughfall drip points.
We introduce a graph...
Please check out this EGU presentation of our perspective article. It includes links to past and current work tackling these challenges. We also share an audiobook version of the article, read by Prof Van Stan: https://youtu.be/JiM2gkfFUVE?si=BmowsT1uoBk317_j
Before the invention of the alphabetic language, humans “read” water directly, deciphering its currents, murmurs, appearances, and the related activities of aquatic and terrestrial life. Water was not merely a physical entity but a dynamic, life-sustaining element that was experienced viscerally. However, with the advent of written language, we now...
Water has been studied by many trades throughout history, from engineering to medicine. In fact, one of the most famous stories in medicine centers around a water pump. Nearly 200 years ago, a cholera outbreak in a London suburb was caused by wastewater contaminating the groundwater that supplied this pump. At this time, physicians were generally i...
“Authenticity” is a concept that ignites powerful debate in our contemporary epoch, often serving as a benchmark for critique. Despite its significance, we have yet to ponder it in this book: Is there an “authentic hydrology,” and what might that be? Even comprehensive hydrology textbooks offer no conclusive description. Some may argue that the aut...
As we grapple with the challenge of harmonizing our understanding and control over water, we are prompted to ask: Can humanity govern water? This question, given the amount of water under our control and within us, mirrors an age-old query: Can we govern ourselves?
Water appears in our lives in various ways. Few appearances are simple and, when human interests are involved, they become highly complex. Complexity poses multiple difficulties, e.g.: complex water phenomena are hard to predict, and they are difficult to communicate effectively and efficiently. Thus, we use reductionism to simplify the complex phe...
Hydrologists, like scientists in other fields, walk a thin line between two realms: the tangible world of physical phenomena and the abstract world of concepts and ideas (often called the “ideal” or “metaphysical” realm). In using models to estimate or predict water-related phenomena, water scientists, decision-makers, stakeholders, etc., wade into...
Understanding the water phenomena that we encounter requires interpretation. Scientists must interpret some view of water and the circumstances framing that view. A “view of water” can come in many forms: empirical measurements, model outputs, an intuition or thought, or a personal observation. We piece together each of these views of water, what H...
Water can “get hard” (as ice, of course). It can also “get soft” by melting or, when already liquid, water is called “soft” if low in certain dissolved salts. These phrases (and how we assume our readers involuntarily interpreted them) illustrate how our perceptions of water are often steeped in gendered language. This anthropomorphic lens dates to...
Western philosophy and science trace their roots to the earliest Greek thinkers documented in history. These thinkers precede much of the surviving written record from the time, a time marked by Plato’s writings about Socrates. Thus, as a group, they are often called the “pre-Socratics.” Among the pre-Socratics, modern hydrologists have developed a...
The weighty problems of the world demand no less than our profound love. Friedrich Nietzsche observed that a thinker’s relationship to their problems greatly influences the outcome of their thoughts. If we engage them impersonally, with the cold touch of detached reasoning, they yield no fruit. Yet when we dare to become personally invested, making...
Does it not seem strange that we pay (much) less for water, a life essential, than for diamonds (for now at least)? This was noticed by Plato, articulated as the “water–diamond paradox” by Adam Smith, and partially explored by Karl Marx at the start of his critique of political economy. Humanity, the self-proclaimed “calculating animal,” has been s...
It is impossible to escape the impression that, since the close of the nineteenth century, science has been increasingly motivated by questionable standards. Instead of designing experiments for the sheer pursuit of knowledge, scientists are compelled to maximize their likelihood of securing money and attention, to fit the demands of society as des...
Nietzsche claims to have recorded a candid conversation between philosophers in the mid-nineteenth century (On the Future of Our Educational Institutions, Friedrich Nietzsche. Macmillan, 1910). They were discussing the future of education in Germany and a subject that arose was “the division of labor in science.” On this topic, one could replace “e...
Water’s presence, forms, and interactions have long held a significant place in the realm of dreams. In the psychoanalytic theories of thinkers like Sigmund Freud, Carl Jung, and Jacques Lacan, water is often interpreted as a powerful symbol representing the unconscious mind or the birthplace of thoughts, ideas, desires, and fears. As a fluid, muta...
By this point, it should be evident that this book serves as a systemic critique of “capital H” Hydrology. This version of Hydrology is a science intrinsically woven into the tapestry of historical, industrial, capitalistic, and technological institutions of its era. Hydrology, in this form, has a problem—or, given the devastating impact water-rela...
Plant canopies divert a portion of precipitation to the base of their stems through "stemflow", a phenomenon that influences the canopy water balance, soil microbial ecology, and intrasystem nutrient cycling. However, a comprehensive integration of stemflow into theoretical and numerical models in natural science remains limited. This perspective e...
The potential for sudden tree dieback exists when there is significant variation in perturbation frequency and intensity, which can alter canopy-atmosphere interactions, like canopy rainfall partitioning. In the context of close-to-nature silviculture practices, dieback trees can endure for several decades in specific environments. Therefore, it is...
Knowledge of the processes and impacts associated with the canopy’s partitioning of rainfall into stemflow (water that drains to the base of tree stems) and throughfall (water that drips through gaps and from canopy surfaces) has expanded in recent years. However, the effect of canopy interactions on the fundamental physical properties of rainwater...
Precipitation that is channeled down tree stems (stemflow) or into drip points of ‘throughfall’ beneath trees results in spatially concentrated inputs of water and chemicals to the ground. Presently, these flows are poorly characterized because of uncertainty about which branches redirect rainfall to one (stemflow) or the other (throughfall drip po...
Intense rain events have become more frequent in some regions due to climate change, and this trend is particularly concerning in dryland regions where the ecological and geomorphological impacts of rainfall are intimately tied to its intensity. The interception of rainfall by vegetation is a critical process in the water balance of drylands; thus,...
Rainwater is a vital resource and dynamic driver of terrestrial ecosystems. Yet, processes controlling precipitation inputs and interactions during storms are often poorly seen, and poorly sensed when direct observations are substituted with technological ones. We discuss how human observations complement technological ones, and the benefits of sci...
Arboreal epiphytes, plants that grow on trees, can significantly increase rainwater storage and evaporation (i.e., "interception") within canopies. Drought conditions may affect this hydrological role, as epiphytes' physiological responses change leaf properties that affect water retention. Drought-induced changes in epiphyte water storage capacity...
The wide variability in functional traits that enable the cosmopolitan distribution of lichens often includes the water storage capacity, S, of their thallus. Lichen S in forest canopies can be large enough to intercept and evaporate significant amounts of rainwater, contributing to the runoff-reduction ecosystem services provided by urban forests;...
For precipitation to reach the surface of vegetated ecosystems, it must first pass through the canopy. A portion of precipitation, stemflow, drains down branches to the stem. This stemflow may wash canopy-dwelling animals (metazoans) to the litter and soils below; however, stemflow metazoans transport has typically been ignored in past research. In...
Plant canopies play critical intermediary roles in the movements of water in both directions along the soil-plant-atmosphere continuum. From the atmosphere to the soil, plant canopies intercept and redirect precipitation and condensation into heterogeneous spatiotemporal patterns of water, nutrient and organismal fluxes at the surface. From the soi...
Biddick and Van Stan II introduce how certain plant species harvest rain.
Water flows through forests in many ways, so it is difficult to understand and predict where and when it will flow. Understanding how water flows through forests is important, as it affects many of the services that forests offer to people, like lumber for houses and cleaner air. Water scientists (called hydrologists) have a way to reduce the compl...
The stemflow may wash canopy-dwelling metazoans to the litter and soils below; however, metazoans transported by stemflow have been typically ignored in past research. In fact, the visual presence of metazoans in stemflow collection bins was reported as “contamination.” Thus, we know little about these organisms’ transfer from plant canopies to the...
Tea is a mix of natural plant chemicals dissolved in water. You should not drink it, but a weak tea drips through a tree’s branches and runs down its trunk when it is raining. The main ingredients in both tea and tree tea are organic molecules. Some, like tannins, are colorful and give tea and tree tea their brownish colors. Others, including sugar...
The forest floor is the forest’s graveyard. There, broken branches and fallen trunks are laid to rest. However, this deadwood still has an important role to play. New deadwood is still covered in bark—a tissue that protects a living tree’s insides from the outside world. The bark makes it difficult for water to enter the dead tree. It repels the ra...
If you look up during a storm or when it is foggy, you may see little rivers flowing down the tree branches above your head. These are called branchflows, and they play an important part in moving water along trees and through forests. For scientists who study water, branchflows are really weird! They do not flow on top of something, like rivers th...
Snowpack accumulation in forested watersheds depends on the amount of snow intercepted in the canopy and its partitioning into sublimation, unloading, and melt. A lack of canopy snow measurements limits our ability to evaluate models that simulate canopy processes and predict snowpack. We tested whether monitoring changes in wind‐induced tree sway...
Stemflow is the spatially‐concentrated input of rain water at the base of a tree, resulting from precipitation draining down tree branches to the stem. Depending on tree shape, stemflow can represent a significant fraction of total rainfall that contacts the tree’s canopy area, and can become chemically enriched along its drainage path. As a result...
Over geologic timescales, forests have intercepted precipitation and thereby modified the intensity, duration, and spatial patterns of water fluxes to forest soils. Across a range of environmental conditions, persistent focused water flows can dissolve carbonate substrates, and form conical dissolution features—termed “dissolution cones.” These con...
Rainfall partitioning by plant canopies can play key roles in dryland ecohydrology by altering the amount, timing and patterns of water receipt to soils. Here, we synthesized interception, throughfall and stemflow observations from 2,297 rainfall events across 40 dryland sites, including 48 plant species. Then, we developed general empirical models...
Compared to leaves, bark is under-studied with regards to its role in the water cycle. This is an important knowledge gap as, unlike leaves, bark is ever-present in forest ecosystems and can represent a significant interface for water interaction. Bark is also porous, hygroscopic, present in litter layers from shedding, as well as on fallen woody d...
You may not pay much attention to fungi growing on the bark of trees in your neighborhood, but there are many fungal species that scientists know have joined the “bark side.” The fungi living on bark do many interesting and surprising things. For example, bark fungi may prowl the bark in search of resources or new habitats. Fungi create tiny versio...
Come join the Bark Side of the Water Cycle! Here's our video abstract for an AGU presentation based on our Perspective article in Frontiers in Forests & Global Change.
https://youtu.be/CGzFNU70yUg
Bark-water interactions are understudied processes in wooded ecosystems. This collection of research highlights evidence of the important roles that bark can play in controlling the amount of water that is returned to the atmosphere during storms, or makes it to the soil, groundwater, and streams, as well as the chemical makeup of that water. As ba...
Contour-felled log debris (CFD) and log erosion barriers (LEB) are two restoration
practices used worldwide on hillslopes to avoid soil erosion after wildfires. Although
significant work has evaluated the effectiveness of these practices on soil loss
prevention, their effects on soil properties have been little researched to date. Here, the
effects...
As the outermost layer of stems and branches, bark is exposed to the influence of atmospheric conditions, i.e., to changes in the air’s relative humidity and wetting during storms. The bark is involved in water interception by tree canopies and stemflow generation, but bark–water relations are often overlooked in ecohydrological research and insuff...
Rainwater is altered hydrologically and chemically as it passes through tree canopies to reach the soil surface, but this aspect of urban forest ecosystems has received less attention than that of natural ecosystems. Hydrological partitioning and changes in solute composition of rainfall were examined in an urban forest within Guangzhou city, in so...
Natural forest regeneration can be a slow and difficult-to-predict process because it is
the result of complex interactions between seedling establishment success and site
factors. Here, we applied a novel “lifetime” modelling approach to account for seed
emergence and seedling survival across site conditions (i.e., seed protection and
canopy cover...
The Cerrado savanna of Brazil is considered the most biodiverse savanna in the world and its vegetation acts as an interface between rainfall and recharge processes for the largest aquifer system (Guarani) in South America. Understanding how major Cerrado tree species affect the amount and patterns of rainfall at the surface, therefore merits scien...
All animals need water to live, but not all of them need to drink it from their surroundings. Drinking free water from rivers or puddles is just one of many ways that animals get the water they need. Until recently, koalas were thought to get most of their water from the leaves that they eat. But, after years of koala watchers getting caught in the...
For one‐third of Earth’s land surface, precipitation passes through tree canopies (as throughfall or stemflow) before entering watersheds. Over a century of research has described fluxes of water and solutes along these “hydrologic highways”, yet little is known about their “traffic” – that is, the organisms and nonliving particulates frequently di...
Pollen shedding can produce rapid, abundant exchanges of nutrient-rich biomass from plant canopies to the surface. When pollen deposits onto understory plants, it can be washed off during storms via throughfall (a drip flux) and stemflow (a flux down plant stems). Pollen deposition may also alter the organismal community on plant surfaces, changing...
There are scientific gray areas where it is unclear whether process representations and assumptions in models have adequate empirical basis. Nonetheless, useful insights can come from interpreting data with the aid of models that use hypothetical parameterizations or process representations, even if they are uncertain and speculative. Indeed, virtu...
The study of stemflow fungi began over 50 years ago. Past work has been performed in different climatic regions of the world, with different sampling methods, by mycologists focusing on different taxonomical groups. Therefore, we aim to synthesize this work to delineate major conclusions and emerging hypothesis. Here, we present: (1) a systematic c...
To date, the perspective of forest ecohydrologists has heavily focused on leaf-water interactions—leaving the ecohydrological roles of bark under-studied, oversimplified, or omitted from the forest water cycle. Of course, the lack of study, oversimplification, or omission of processes is not inherently problematic to advancing ecohydrological theor...
The authors regret that the abstract and key words for this article were not included in the final publication—despite these having been included in the manuscript submission throughout the peer review process. The abstract and key words are obviously important components of a publication, especially in the digital age where they are (1) the only p...
This study evaluates soil hydraulic conductivity (SHC) and water repellency (SWR) in three mixed forest stands in relation to site plant and soil characteristics. The studied forest stands were: i) Pinus nigra Arn. ssp salzmannii and Quercus ilex; ii) Pinus nigra Arn. ssp salzmannii and Juniperus Thurifera; iii) Pinus nigra Arn. ssp salzmannii, Que...
These are the introductory videos for an #AGU2020 virtual conference session "Precipitation Partitioning by Vegetation." The first interaction between precipitation and land surface is often with a plant canopy, which partitions precipitation into throughfall, stemflow or interception. Studying these processes answers important questions for many f...
Post-fire environmental conditions can heavily influence the natural regeneration of pine species in Mediterranean forests. Therefore, enhancing post-fire recovery of pine species is fundamental for effective ecological restoration of Mediterranean forests. In this study, the effects of a post-fire restoration treatment on the seedling emergence an...
The role of crop canopies in the global water cycle is a topic of increasing international interest. How much rain and sprinkler-irrigation water are returned to the atmosphere or reach the soils beneath crop canopies, and the pathways of those water inputs at the soil, are linked to agricultural productivity and sustainability. This concise-format...
In vegetated landscapes, rain must pass through plant canopies and litter to enter soils. As a result, some rainwater is returned to the atmosphere (i.e., interception, I) and the remainder is partitioned into a canopy (and gap) drip flux (i.e., throughfall) or drained down the stem (i.e., stemflow). Current theoretical and numerical modeling frame...
When it rains over vegetation, plants have an opportunity to get a limited supply of freshwater. A portion of rain drains directly to the soil down a plant stem, in a hydrologic flux called “stemflow.” For short vegetation with shallow roots, which provide ground cover for most vegetated ecosystems around the globe (including forest understories),...
Here, we visit a community of trees living along the Georgia coast, just above the high tide line, on a little lump of sand called a "hammock." This hammock plant community is battered by a hurricane. The plants that survive soon realize that they have fallen prey to a hydrological torture wrack - one composed of the salty corpses of their neighbor...
Hurricanes can cause immediate catastrophic destruction of marsh vegetation and erosion of soils; however, they also have long-lasting ecological impacts. Those impacts include the deposition of
tremendous amounts of saltmarsh litter (‘wrack’) onto upland ecosystems, the hydrologic effects of which have not previously been investigated. When Hurric...
The science comic 'Roots of the Past nourish present research' leads two students on a wild time travel to the first observations and observatories of plants and precipitation – the story of ecohydrology. Using past knowledge and new technologies they develop ideas for their own research.
Der Wissenschaftscomic 'Wurzeln der Vergangenheit ernähren Forschung der Gegenwart' führt zwei Studierende auf ein wilde Zeitreise zu den ersten Beobachtungen und Observatorien von Pflanzen und Niederschlag – der Geschichte der Ökohydrologie. Dabei entwickeln sie Ideen für Ihre eigene Forschung.
A portion of precipitation drains to the surface down plant stems, as “stemflow.” Although per observations to date, stemflow rarely represents >2% of gross precipitation in forests, it can result in larger water fluxes to near-stem soils that are hypothetically more important to roots. The ecohydrological importance of stemflow is often predicated...
This is a fun, short (2-page) outreach contribution to the national Society of Municipal Arborists' Roundtable discussion, "Where Urban Forests, Stormwater, and Watersheds Meet." Here, I briefly discuss why/how precipitation partitioning by urban forests is relevant to urban watershed management. In an effort to highlight the many tricks trees have...
There are multiple distinct habitats for microbiota inhabiting the plant microbiome (phyllosphere, endosphere, litter, rhizosphere) and habitats that act as additional sources (and sinks) of microbes and nutrients for the plant microbiome (atmosphere, pedosphere, bedrock, and fauna). These habitats harbor distinctive microbial communities that diff...
The amount and patterning of precipitation beneath vegetation is determined by throughfall and stemflow. Throughfall is the portion of precipitation that falls through, or drips from, the canopy; whereas, stemflow is the portion that drains down the stem. This chapter briefly synthesises throughfall and stemflow methods, data and major drivers of v...
Dissolved organic matter (DOM) is a master variable that modulates the form and function of many ecosystems. Approximately, half of the mass of DOM is carbon. Fluxes of DOM transfer carbon and other vital elements between ecosystems and between organisms (e.g., trees to bacteria) and components (e.g., vegetation to soil) within ecosystems. The DOM...
This chapter presents a history of the interdisciplinary field focused on improving our understanding of the first step in the terrestrial hydrologic cycle: precipitation partitioning by vegetation. We describe the origins of interest, rooted in observations from “The Father of Botany,” Theophrastus (350 BCE) and synthesize the early formal hydrolo...
Redistribution of precipitation water by plant canopies increases the spatial variation of net precipitation at the surface, affecting soil moisture patterns, localized preferential flow, and soil biogeochemical processes. This chapter reviews methods for assessing and the current state of knowledge on spatial patterns of the two net precipitation...
Trees impact surface stormwater runoff, soil moisture, streamflow, water quality, and air temperatures by intercepting precipitation (rain and snow), enhancing soil water infiltration, shading surfaces, and evapotranspiring water. These impacts affect human health and well-being. Many of these tree impacts remain to be more accurately quantified an...
The interception of precipitation by vegetation has important consequences for climate and water resources. Although canopy interception has been studied for centuries, many fundamental unknowns remain. We present persistent questions that reflect challenges in measuring, representing, and understanding how terrestrial ecosystems intercept, partiti...
Water storage on tree crowns, trunks, the understory, and litter is, in many respects, one of the simplest water balance components of vegetated ecosystems, but one that is rarely parameterized in detail. Interception processes are often analogized and parameterized as the dynamic (filling and emptying) of static reservoirs, but canopy storage rese...
For close to a century, scientists have recognized the important role of throughfall and stemflow (precipitation water that falls through plant canopies and runs down plant stems, respectively) in the cycling of materials. These “hydrologic highways” carry atmospherically deposited and canopy-derived materials from the top of the plant canopy to th...
This book presents research on precipitation partitioning processes in vegetated ecosystems, putting them into a global context. It describes the processes by which meteoric water comes into contact with the vegetation's canopy, typically the first surface contact of precipitation on land. It also discusses how precipitation partitioning by vegetat...
Study region: Maize farmland in Varamin, located southwest of Tehran (Iran).
Study focus: The aims of this study were to: (1) monitor throughfall and stemflow during rainstorms beneath maize canopies over two growing seasons (2015, 2016); (2) evaluate the effect of maize canopy structure (leaf area index, plant height) on throughfall, stemflow, an...
In 2020, let's make stemflow unit-ed again: https://youtu.be/4vPk9m45V0c ...
From inside the stemflow research community, the past decade’s progress might look great: 1) the number of papers published on stemflow per year has doubled; 2) citations of stemflow publications have more than doubled; and 3) the number of research sites monitoring stemf...
The interception of rainfall by trees enriches rainwater with tree-derived dissolved organic matter (tree-DOM), which represents the first terrigenous source of DOM during storm events. The tree-DOM is then exported from the canopy via rainfall that drips from leaves and branches (throughfall) or is funneled down the tree trunk (stemflow) to the fo...
In vegetated landscapes, rain must pass through plant canopies and litter to enter soils. As a result, some rainwater is returned to the atmosphere (i.e., interception, I) and the remainder is partitioned into a canopy (and gap) drip flux (i.e., throughfall) or drained down the stem (i.e., stemflow). Current theoretical and numerical modelling fram...
The first contact between precipitation and the land surface is often a plant canopy. The resulting precipitation partitioning by vegetation returns water back to the atmosphere (evaporation of intercepted precipitation) and redistributes water to the subcanopy surface as a "drip" flux (throughfall) and water that drains down plant stems (stemflow)...
Arboreal epiphytes (plants residing in forest canopies) are present across all major climate zones and play important roles in forest biogeochemistry. The substantial water storage capacity per unit area of the epiphyte "bucket" is a key attribute underlying their capability to influence forest hydrological processes and their related mass and ener...
Aim of study: To understand throughfall (TF) sensitivity to variability in rainfall amount (Pg) for typical forest sites across the main climate types of Iran.
Area of study: Nine forest stands of several common native and introduced tree species situated in all common Iranian climate types, but located primarily in northern Iran.
Material and me...
This is the story of Precipita, the waterwitch of Leipzig Germany, and the critical roles that urban forests play in protecting the city from her hydrological whims!
As we made this comic with the City of Leipzig in Germany we also translated it into German.
The science comic is based on a book chapter "Urban Forestry: An Underutilized Tool in Wa...
Forest canopy surfaces (phyllosphere) host a dynamic, diverse, and populous bacterial community that is washed thoroughly by storms. Interactions with the phyllosphere dramatically alter the composition of rainfall reaching the surface. Here, we report how rainfall bacterial community composition is altered as it drains from canopy surfaces/through...
Scientists are trained to tell stories, scientific stories. Training is also needed to comprehend and contextualize these highly nuanced and technical stories because they are designed to explicitly convey scientific results, delineate their limitations, and describe a reproducible “plot” so that any thorough reenactment can achieve a similar concl...
Non-vascular vegetation has been shown to capture considerable quantities of rainfall, which may affect the hydrological cycle and climate at continental scales. However, direct measurements of rainfall interception by non-vascular vegetation are confined to the local scale, which makes extrapolation to the global effects difficult. Here we use a p...
Questions
Questions (3)
The argument is often made in stemflow research that “reporting stemflow as a percentage of rainfall disconnects it from its input area" - thus, we should use the funneling or enrichment ratio. However, is this true? Does expressing stemflow as a fraction of rainfall create a "disconnect" between stemflow and its input area? I believe it does not, i.e., estimating relative stemflow across the canopy says nothing about stemflow's input area. Perhaps this is, unwittingly, a rhetorical statement, used to persuade others to report stemflow in a way that makes it look important "despite being a small fraction of rainfall"?
Of course, stemflow CAN be important hydrologically, ecologically, and biogeochemically. However, I am not sure these funneling metrics can tell us when/how stemflow is important. I'm also not sure how these metrics fit into theoretical and numerical models. So far, these thoughts have been shared through static presentations and publications. But, that really limits the conversation. So, I figured I'd ask the RG community: why do we, in the stemflow community, still report stemflow in these unitless (funneling and enrichment) ratios? In what ways do these ratios actually improve our understanding of stemflow, stemflow-environment interactions, or integrate stemflow into theory/models?
