David M Eissenstat

• PhD
• Professor Emeritus at Pennsylvania State University

Aims Global change threatens ecosystem functions, including those driven by soil fauna. In temperate forests, soil nutrients, litter quality, and microarthropods are essential players during litter decomposition. However, the impact of nutrient enrichment on the functional role of soil fauna remains poorly understood. Methods We used a full factor...

Leaf decomposition varies widely across temperate forests, shaped by factors like litter quality, climate, soil properties, and decomposers, but forest heterogeneity may mask local tree influences on decomposition and litter‐associated microbiomes. We used a 24‐yr‐old common garden forest to quantify local soil conditioning impacts on decomposition...

In grapevine, metabolic activity of absorptive roots changes rapidly as roots age but it is unclear whether nearby microbial assemblages shift as well. Here, we investigated whether first-order root age affects bacterial and fungal variation adjacent to the root surface, and whether root age should be integrated into future studies on root function...

Among the contributors to soil CO 2 efflux, there remains uncertainty about the contribution of root activity to the overall soil efflux. Soil water and temperature frequently have been used to predict a large portion of the variation in soil CO 2 efflux. We hypothesized that fine‐root dynamics explain most of the remaining variability in soil CO 2...

Traditionally, fine roots were grouped using arbitrary size categories, rarely capturing the heterogeneity in physiology, morphology and functionality among different fine root orders. Fine roots with different functional roles are rarely separated in microbiome‐focused studies and may result in confounding microbial signals and host‐filtering acro...

While the invasive spotted lanternfly, Lycorma delicatula (White) [Hemiptera: Fulgoridae], continues to expand its range in the United States, there remains a knowledge gap regarding the economic threat that this pest presents to forest ecosystems and production nurseries. L. delicatula uses several common hardwood trees as hosts and a previous stu...

Plant species identity influences soil microbial communities directly by host specificity and root exudates, and indirectly by changing soil properties. As a native pioneer species common in early successional communities, Masson pine (Pinus massoniana) forests are widely distributed in subtropical China, and play a key role in improving ecosystem...

In vineyards, cover crops typically grow concurrently with grapevines and can impart a multitude of agroecosystem services; yet concerns over potential disservices might limit adoption. Reductions in yield and vegetative growth are key disservices of concern, but at sites with high soil resources, reducing excessive vegetative growth is often consi...

INTRODUCTORY PARAGRAPH Root-associated microbial communities are increasingly recognized as key contributors to plant function, but we still understand little about the factors driving interactions between microbes and individual roots. To have thorough understanding of this system, we must consider the immense functional and spatial heterogeneity...

Spotted lanternfly (SLF; Lycorma delicatula White; Hemiptera: Fulgoridae) invaded the US from Asia and was first detected in 2014; currently, populations have established in 14 states primarily in the Northeast and Mid-Atlantic. It feeds voraciously on phloem sap from a broad range of host plants, with a preference for tree of heaven (Ailanthus alt...

The rhizosphere is a nexus for plant–microbe interactions and, as a host-structured environment, a location of high activity for distinct microbes and plant species. Although our insights into this habitat have exploded in recent years, we are still limited in our ability to answer key questions about the specificity of these root-microbial relatio...

Spatiotemporal heterogeneity in soil CO2 efflux (FS) underlies one of our greatest gaps in understanding global carbon (C) cycles. Though scientists recognize this heterogeneity, FS sampling schemes often average across spatial heterogeneity or fail to capture fine temporal heterogeneity, and many ecosystem models assume flat terrain. Here, we test...

Aims Root traits associated with resource foraging, including fine-root branching intensity, root hair, and mycorrhiza, may change in soils that vary in rock fragment content (RFC), while how these traits covary at the level of individual root branching order is largely unknown. Methods We subjected two xerophytic species, Artemisia vestita (subsh...

Aims Complex topography, a common feature of forested areas, generates unique environmental gradients that may shape root dynamics in unexpected ways. Nevertheless, belowground studies rarely capture the environmental gradients imposed by complex topography, such as those found along hillslopes. This begs the question: how much information is lost...

Woodlands are pivotal to carbon stocks, but the process of cycling C is slow and may be most effective in the biodiverse root zone. How the root zone impacts plants has been widely examined over the past few decades, but the role of the root zone in decomposition is understudied. Here, we examined how mycorrhizal association and macroinvertebrate a...

Vertical root segregation can be a key underpinning of species co-existence through below-ground niche partitioning but has rarely been tested in diverse forest communities. We randomly sampled > 4000 root samples from 625 0-30 cm soil profiles in a subtropical forest in China to determine the degree of vertical root segregation among 109 woody spe...

Aims Root traits associated with resource foraging, including fine-root branching intensity, root hair and mycorrhiza, may change in soils with various physical structure indicated by rock fragment content (RFC), while how these traits covariate at the level of individual root branching order is largely unknown. Methods We subjected two xerophytic...

Belowground biodiversity loss from anthropogenic causes is far less addressed and quantified than aboveground biodiversity loss. Soil fauna supports soil productivity and biogeochemical cycles, and their decline needs further research. We tested the effects of a woodland harvest gradient (0, 30, 50, and 70% biomass removal) on litterfall, mesofauna...

Root lifespan, often is estimated in landscape- and ecosystem-level carbon models using linear approximations. In water manipulation experiments, fine root lifespan can vary with soil water content. Soil water content is generally structured by complex topography, which is largely unaccounted for in landscape- and ecosystem-scale carbon models. Top...

Vertical root segregation and the resulting niche partitioning can be a key underpinning of species coexistence. This could result from substantial interspecific variations in root profiles and rooting plasticity in response to soil heterogeneity and neighbours, but they remain largely untested in forest communities. In a diverse forest in subtropi...

Soil carbon may be enhanced in agroecosystems by increasing root density throughout the soil profile. In vineyards and orchards, groundcovers that grow concurrently with the grapevines directly increase shallow root biomass and may induce deeper rooting of the fruit crop. We examined root distributions and soil properties associated with soil carbo...

Fine roots vary dramatically in their functions, which range from resource absorption to within-plant resource transport. These differences should alter resource availability to root-associated microorganisms, yet most root microbiome studies involve fine root homogenization. We hypothesized that microbial filtering would be greatest in the most di...

AimsKey functional root traits, including mycorrhizal association and root diameter, can help project ecosystem processes like root turnover and soil carbon sequestration. It is less clear, however, how such traits relate to variations in soil biology and chemistry. Here, we examined the impact of tree species with varied root traits on soil proper...

Fine roots play a significant role in plant and ecosystem respiration (RS); therefore, understanding factors controlling that process is important both to advancing understanding and potentially in modelling carbon (C) budgets. However, very little is known about the extent to which ectomycorrhizal (ECM) identity may influence RS or the underlying...

1. Tissue nitrogen (N) concentration has been correlated with respiration (RS) across plants of different life-forms, functional and phylogenetic groups, plant organs and ectomycorrhizae of different fungal species. Nothing is known, however, if a similar relationship exists in other organisms like fungi. 2. Here, we explored the N-RS relationship...

AimsRoot dynamics plays a fundamental role in determining carbon allocation and other main ecological processes in grasslands. Understanding the responses of root activities to ongoing warming in grazed alpine meadows enable us to predict the potential changes in the carbon budget and ecosystem functions in alpine regions.Methods We conducted a con...

Long-term minirhizotron observations of absorptive fine roots provide insights into seasonal patterns of belowground root production and carbon dynamics. Our objective was to compare root dynamics over time across mature individuals of 11 temperate trees species: five evergreen and six deciduous. We analyzed the timing and growth on 1st-and 2nd-ord...

In a forested watershed, identity of tree species and topographical position could be important driving factors shaping mycorrhizal fungal communities. Here we aimed to disentangle the contributions of these two factors to mycorrhizal fungal community structure. We collected tree roots colonized by either arbuscular mycorrhizal (AM) or ectomycorrhi...

Environmental filtering and limiting similarity mechanisms can simultaneously structure community assemblages. However, how they shape the functional and phylogenetic structure of root neighborhoods remains unclear, hindering the understanding of belowground community assembly processes and diversity maintenance. In a 50‐ha plot in a subtropical fo...

Bark decomposition in white oak soil outperforms eastern hemlock soil, while bark type leads to consistent changes in soil microbial composition

Premise: While root-order approaches to fine-root classification have shown wide utility among wild plants, they have seen limited use for perennial crop plants. Moreover, inadequate characterization of fine roots across species of domesticated perennial crops has led to a knowledge gap in the understanding of evolutionary and functional patterns...

Soils derived from different lithologies and their controls on preferential flow remain underexplored in forested landscapes. In the same lithology, the propensity for preferential flow occurrence at different hillslope positions also remains largely elusive. By utilizing a soil moisture response time method, we compared preferential flow occurrenc...

Key Message Nitrogen addition leads to large increases in shoot growth but limited increases in root growth and reductions in mycorrhizal colonization of Sorbus pohuashanensis and Acanthopanax sessiliflorus. Abstract Soil in the cultivated fields of Changbai Mountain region of China is rich in phosphorus (P) and deficient in nitrogen (N) for most...

The terrestrial carbon (C) cycle remains the least constrained component in the global C cycle, partly due to the difficulty of quantifying C sources and sinks in complex terrain. In this paper, we used observations at the Shale Hills Critical Zone Observatory and a biogeochemistry model, Biome‐BGC, to study the spatial distribution of C stocks and...

Aims Vegetative groundcover and rootstock selection are popular growth control practices for fruit and nut crops. Theoretically, plant potential growth rate should influence competitive effectiveness; however, it is unclear if rootstock vigor alters crop productivity when groundcover is present. Methods In a humid-climate vineyard we grew young gr...

We thank reader Joseph Craine for pointing out three inadvertent errors in this Letter. First, 4 of the 71 divergence dates extracted from ref. ¹ of this Amendment and used in Fig. 1b of the original Letter were overestimated. The correct values are 45 million years ago (Ma) for Apocynaceae, 51 Ma for Anacardiaceae, 40 Ma for Primulaceae, and 53 Ma...

Nitrogen (N) enrichment often increases aboveground net primary productivity (ANPP) of the ecosystem, but it is unclear if belowground net primary productivity (BNPP) track responses of ANPP. Moreover, the frequency of N inputs may affect primary productivity but is rarely studied. To assess the response patterns of above‐ and belowground productiv...

In perennial plants, root metabolic activity decreases as absorptive roots age and eventually senesce. How this change in activity influences fungi inhabiting those roots is not well known. Particularly for arbuscular mycorrhizal (AM) fungi that rely exclusively on plant-derived carbon, these changes may exert significant pressure on fungi, leading...

The original version of this article unfortunately contained an error in Fig. 1. The y-axis labels for Fig. 1b and d are switched. The correct figures are shown here.

Rising atmospheric CO2 concentrations have increased interest in the potential for forest ecosystems and soils to act as carbon (C) sinks. While soil organic C contents often vary with tree species identity, little is known about if, and how, tree species influence the stability of C in soil. Using a 40 year old common garden experiment with replic...

Core Ideas Studying the critical zone requires targeted research on water, energy, gas, solutes, and sediments. The SSHCZO targets a 165‐km ² watershed on sedimentary rocks in the northeastern United States. One SSHCZO subcatchment, Shale Hills, provides extraordinary data describing a shale CZ. The Susquehanna Shale Hills Critical Zone Observator...

Background and aims Root and mycorrhizal fungal foraging in nutrient-rich patches is an energy-intensive process, and shifts in carbon (C) availability may affect foraging strategies. We hypothesize that when trees are C limited, they will prioritize root and mycorrhizal hyphal growth in nutrient-rich soil patches. Methods Apple (Malus domestica B...

Limiting irrigation to increase fruit quality as well as conserve limited water resources is of increasing importance. We examined the links of aboveground growth and physiology to root growth and distribution under cultural practices associated with restricted irrigation and mulching in an apple (‘Gala/M.9’; Malus x domestica Borkh.) orchard in a...

Core Ideas Two new subcatchments are used to test the importance of lithology and land use. Differences in lithology and land use result in differences in soils and waters. Despite differences, all catchments have a shallow and a deep water table. The relative importance of flow paths controls distinct chemistry response to discharge. Cross‐site co...

Terrestrial carbon processes are affected by soil moisture, soil temperature, nitrogen availability and solar radiation, among other factors. Most of the current ecosystem biogeochemistry models represent one point in space, and have limited characterization of hydrologic processes. Therefore, these models can neither resolve the topographically dr...

Temperature is commonly assumed to act as the primary constraint on the timing of plant growth, and strong advances in plant phenology have been seen with recent atmospheric warming. The influence of temperature on the timing of root growth, however, is less clear, and controls on root phenology are not well understood. The influence of temperature...

Background and aims: Understanding root traits and their trade-off with other plant processes is important for understanding plant functioning in natural ecosystems as well as agricultural systems. The aim of the present study was to determine the relationship between root morphology and the hydraulic characteristics of several orders of fine root...

This corrects the article DOI: 10.1038/nature25783.

Locally coexisting tree species of temperate forests often vary widely in the diameter of their absorptive roots, resulting in contrasting strategies of root foraging within soil nutrient hot spots. We hypothesized that root diameter would also influence the extramatrical hyphal exploration distance of the mycorrhizal fungal community due to coevol...

Plant roots have greatly diversified in form and function since the emergence of the first land plants1,2, but the global organization of functional traits in roots remains poorly understood3,4. Here we analyse a global dataset of 10 functionally important root traits in metabolically active first-order roots, collected from 369 species distributed...

Plant roots and the associated mycorrhizal fungal hyphae often selectively proliferate into patchily distributed soil nutrient hotspots, but interactions between these two components of a mycorrhizal root system are usually ignored or experimentally isolated in nutrient foraging studies. From studies in which both roots and mycorrhizal hyphae had a...

Trees, the most successful biological power plants on earth, build and plumb the critical zone (CZ) in ways that we do not yet understand. To encourage exploration of the character and implications of interactions between trees and soil in the CZ, we propose nine hypotheses that can be tested at diverse settings. The hypotheses are roughly divided...

Many areas in the world are characterized by shallow soils underlain by weathered bedrock, but root-rock interactions and their implications for regolith weathering are poorly understood. To test the role of tree roots in weathering bedrock, we excavated four pits along a catena in a shale-dominated catchment at the Susquehanna Shale Hills Critical...

Plants compete for nutrients using a range of strategies. We investigated nutrient foraging within nutrient hot‐spots simultaneously available to plant species with diverse root traits. We hypothesized that there would be more root proliferation by thin‐root species than by thick‐root species, and that root proliferation by thin‐root species would...

Trees, the most successful biological power plants on earth, build and plumb the critical zone (CZ) in ways that we do not yet understand. To encourage exploration of the character and implications of interactions between trees and soil in the CZ, we propose nine hypotheses that can be tested at diverse settings. Depending upon one's disciplinary b...

Trait-based approaches provide a useful framework to investigate plant strategies for resource acquisition, growth, and competition, as well as plant impacts on ecosystem processes. Despite significant progress capturing trait variation within and among stems and leaves, identification of trait syndromes within fine-root systems and between fine ro...

Background Shifts in phenology have been widely reported in response to global warming and have strong effects on ecosystem processes and greenhouse gas emissions. It is well documented that warming generally advances many phenophases of aboveground plant phenology, but its influence on root phenology is unclear. Most terrestrial biosphere models a...

Premise of the study: Plant phenology influences resource utilization, carbon fluxes, and interspecific interactions. Although controls on aboveground phenology have been studied to some degree, controls on root phenology are exceptionally poorly understood. Methods: We used minirhizotrons to examine the timing of grape root production over 5 yr...

In forested ecosystems, topography and tree species contribute to spatial variability in carbon (C) dynamics through differential rates of C uptake and storage; therefore, estimates of species-specific and spatial variability in C can strengthen ecosystem budgets. To produce such estimates, we deconstructed watershed-scale C and component pools (e....

Here, in the letter published in this issue of New Phytologist (pp. 310-312), 'Fine roots - functional definition expanded to crop species?' Dr. Zobel emphasizes the importance of heterogeneity within crop-root systems.

Photosynthesis by leaves and acquisition of water and minerals by roots are required for plant growth, which is a key component of many ecosystem functions. Although the role of leaf functional traits in photosynthesis is generally well understood, the relationship of root functional traits to nutrient uptake is not. In particular, predictions of n...

The roots of the majority of tree species are associated with either arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) fungi. The absorptive roots of tree species also vary widely in their diameter. The linkages between root thickness, mycorrhiza type and nutrient foraging are poorly understood. We conducted a large root ingrowth experiment in th...

Trees are responsible for the majority of precipitation recycling over land and can affect soil water storage, stream flow, and ground water recharge. Historically, water has not often been limiting in eastern U.S. forests. As a result, little work has been done to understand the timing of water use by vegetation in these systems. We used deuterium...

The application of multiple isotope proxies on the same location within a Critical Zone (CZ), which we term “CZ-tope”, elucidates the interactions of geochemical, geomorphological, hydrological and biological processes together with anthropogenic influences in the CZ across widely disparate timescales. We exemplify the CZ-tope approach by summarizi...

Tissue nitrogen (N) concentration has been correlated with respiration ( RS ) across plants of different life‐forms, functional and phylogenetic groups, plant organs and ectomycorrhizae of different fungal species. Nothing is known, however, if a similar relationship exists in other organisms like fungi. Here, we explored the N‐ RS relationship acr...

Root respiration is a major contributor to terrestrial carbon flux. Many studies have shown root respiration to increase with an increase in root tissue nitrogen (N) concentration across species and study sites. Studies have also shown that both root respiration and root N concentration typically decrease with root age. The effects of added N may d...

Many scientists have begun to refer to the earth surface environment from the upper canopy to the depths of bedrock as the critical zone (CZ). Identification of the CZ as an integral object worthy of study implicitly posits that the study of the whole earth surface will provide benefits that do not arise when studying the individual parts. To study...

Background and Aims Cover crops limit canopy growth in fruit crops to varying magnitudes but mechanisms are poorly understood. Root responses of mature grapevines to understory grass were evaluated in a temperate, humid region of USA. We hypothesized that mature grapevines competing with understory grass would show deeper root distribution with dee...

Plant phenology is one of the strongest indicators of ecological responses to climate change, and altered phenology can have pronounced effects on net primary production, species composition in local communities, greenhouse gas fluxes, and ecosystem processes. Although many studies have shown that aboveground plant phenology advances with warmer te...

Arctic ecosystems contain vast stores of soil carbon (C), yet our understanding of the factors controlling CO2 efflux from tundra soils remains poor. Partitioning soil respiration (R S) into heterotrophic (R H) and autotrophic (R A) sources can help elucidate the relative contributions from microbial breakdown of soil organic matter (SOM) and root...

We investigated depth of water uptake of trees on shale-derived soils in order to assess the importance of roots over a meter deep as a driver of water use in a central Pennsylvania catchment. This information is not only needed to improve basic understanding of water use in these forests but also to improve descriptions of root function at depth i...

Many scientists have begun to refer to the earth surface environment from the upper canopy to the depths of bedrock as the critical zone (CZ). Identification of the CZ as a worthy object of study implicitly posits that the study of the whole earth surface will provide benefits that do not arise when studying the individual parts. To study the CZ, h...

Aims In addition to multiple above- and belowground abiotic factors, root herbivory can be an important determinant of root lifespan. In this study, we investigated the relationship between fine-root soluble phenolic content, a putative measure of chemical defense against herbivory, and explicit factors that have previously been related to fine-roo...

• The identification of plant functional traits that can be linked to ecosystem processes is of wide interest, especially for predicting vegetational responses to climate change. Root diameter of the finest absorptive roots may be one plant trait that has wide significance. Do species with relatively thick absorptive roots forage in nutrient-rich p...

In most cases, both roots and mycorrhizal fungi are needed for plant nutrient foraging. Frequently, the colonization of roots by arbuscular mycorrhizal (AM) fungi seems to be greater in species with thick and sparsely branched roots than in species with thin and densely branched roots. Yet, whether a complementarity exists between roots and mycorrh...

Fine roots acquire essential soil resources and mediate biogeochemical cycling in terrestrial ecosystems. Estimates of carbon and nutrient allocation to build and maintain these structures remain uncertain due to challenges in consistent measurement and interpretation of fine-root systems. Traditionally, fine roots have been defined as all roots le...

Many surface soils are enriched in metals due to anthropogenic atmospheric inputs. To predict the persistence of these contaminants in soils, factors that impact rates of metal removal from soils into streams must be understood. Experiments at containerized seedling (“mesocosm”), pedon, and catchment scales were used to investigate the influence of...

Aims Leaf and root phenology play important roles controlling plant productivity and ecosystem function, yet, few studies link patterns of leaf and root phenology across woody species. Trees with diffuse-porous wood anatomy tend to leaf-out before ring-porous species and we expected that increases in transpiration with spring leaf-out would be coup...

Large uncertainties surrounding root-specific parameters limit model descriptions of belowground processes and ultimately hinder understanding of belowground carbon (C) dynamics and terrestrial biogeochemistry. Despite this recognized shortcoming, it is unclear which processes warrant attention in model development, given the computational cost of...

Background/Question/Methods Mycorrhizal fungi can strongly influence nutrient acquisition by plants. The extent that mycorrhizas benefit nutrient acquisition among tree species is likely related to their root morphology.Compared to tree species with fine roots, species with coarse absorptive roots are predicted to generate more mycorrhizal hyphae...

The timing of fine root production and turnover strongly influences both the seasonal potential for soil resource acquisition among competing root systems and the plant fluxes of root carbon into soil pools. However, basic patterns and variability in the rates and timing or fine root production and turnover are generally unknown among perennial pla...

Although understanding the timing of the deposition of recent photosynthate into fine roots is critical for determining root lifespan and turnover using isotopic techniques, few studies have directly examined the deposition and subsequent age of root carbon. To gain a better understanding of the timing of the deposition of root carbon, we labeled f...

Resource exploitation of patches is influenced not simply by the rate of root production in the patches but also by the lifespan of the roots inhabiting the patches. We examined the effect of sustained localized nitrogen (N) fertilization on root lifespan in four tree species that varied widely in root morphology and presumed foraging strategy. The...

Background/Question/Methods The vertical distribution and function of tree roots in the soil affect ecosystem water balance and may also drive species distributions and competition. However, it is not well understood what factors drive the depth of water uptake. To this end, we studied the role of tree species, slope position, and soil characteri...