Differentiation, adaptation, and perseverance: Maturing conceptualizations of education-focused science faculty in the United States.

Science education reform has been underway for almost a century with the general aim to engage students and train scientists needed to find solutions to global challenges, and also ensure a general public well disposed towards science. In an effort to aid science reform, more recently, colleges and universities have been augmenting their academic workforce by embedding education-focused science faculty into science departments. However, little research has investigated how this approach, and the identity of these faculty, may be changing over time. Here we investigate how conceptualizations of professional identities of these faculty across the United States have changed over the last two decades. We found three professional identities amongst these faculty: Science Faculty with Education Specialties (SFES), Discipline-Based Education Researchers (DBER), and faculty who identify as both SFES and DBER. Evidence indicates this is a maturing field within higher-education science departments, with more direct hiring and training pathways, but with potentially diminishing agency. Finally, data reveal resilience and perseverance despite negative biases from peers and college administrators, especially at PhD-granting institutions.

Disciplinary Bias, Money Matters, and Persistence: Deans' Perspectives on Science Faculty with Education Specialties (SFES).

The phenomenon of embedding Science Faculty with Education Specialties (SFES) in science departments is well documented. However, the perspectives of academic leaders have not been systematically studied. To investigate these perspectives, we conducted an interview study of college of science deans in the California State University system, which offers a defined higher education context in which to sample across a range of institution types and cultures. While deans were aware of and positive about SFES as potential change agents, most deans also evidenced casual bias against science education efforts and experts. Deans mentioned that education reform efforts by SFES were primarily driven by external policy and funding mandates, causing concern that support for such positions and scholarly work could evaporate if external pressures recede. The majority of deans stated that the SFES phenomenon had persisted over the last decade and continued to grow. Findings reported here document tacit assumptions that science education efforts may not count as science and reveal a lack of cultural integration of science education efforts into the sciences in higher education. Such findings should give biology educators, reformers, and researchers pause, as well as fresh incentive to engage more fully and regularly with administrators about their work.

Pods as sails but not as boats: dispersal ecology of a habitat-restricted desert milkvetch.

PREMISE: Adaptive seed dispersal mechanisms are fundamental to plant fitness, but dispersal advantage is scale-dependent. We tested the hypothesis that informed dispersal in response to an environmental cue enables dispersal by wind on a local scale for Astragalus holmgreniorum, a desert species restricted to swales and wash skirts with overland flow, but prevents longer-distance dispersal by water into unfavorable wash habitats. METHODS: Pod biomechanics in A. holmgreniorum lead to major shape modifications with changes in moisture content. We performed laboratory experiments to examine the interaction of pod shape with wind and water, and conducted field experiments in A. holmgreniorum habitat evaluating the roles of wind, water, and seed predators on dispersal. RESULTS: Dry pods exhibit a flattened crescent shape with partial dehiscence that facilitated wind dispersal by ground tumbling and seed scattering in laboratory experiments. Rain simulation experiments showed that even small precipitation events returned wetted pods to their cylindrical shape and opened the dorsal suture, exposing the seeds. In the field experiments, dry pods were moved locally by wind, whereas rain caused pod opening and washing out of seeds in place. Seed predators had minimal effect on pod movement. CONCLUSIONS: Astragalus holmgreniorum exhibits pod structural remodeling in response to environmental change in a striking and novel demonstration of informed dispersal. Wind-driven movement of dry pods facilitates local seed dispersal, but rain causes pods to open and release seeds, ensuring that they are not transported out of suitable habitats and into active washes where they would be lost from the seed bank.

Evolving roles of scientists as change agents in science education over a decade: SFES roles beyond discipline-based education research.

To what extent have positions for science education specialists as change agents within science departments persisted and evolved over the past decade? We addressed this question by studying a population of Science Faculty with Education Specialties (SFES) first described in 2008. SFES are university science faculty who engage in undergraduate science education, K-12 science education, and/or research in science education. Compared to a decade ago, SFES are now more prevalent and more likely to be formally trained in science education. Many identify as discipline-based education researchers (DBER) but assert that their SFES and DBER roles are nonequivalent. SFES have garnered university administrator support through varied science education activities, and these insights into the evolving role of scientists in science education have implications for many stakeholders.

A Community-Building Framework for Collaborative Research Coordination across the Education and Biology Research Disciplines.

Since 2009, the U.S. National Science Foundation Directorate for Biological Sciences has funded Research Coordination Networks (RCN) aimed at collaborative efforts to improve participation, learning, and assessment in undergraduate biology education (UBE). RCN-UBE projects focus on coordination and communication among scientists and educators who are fostering improved and innovative approaches to biology education. When faculty members collaborate with the overarching goal of advancing undergraduate biology education, there is a need to optimize collaboration between participants in order to deeply integrate the knowledge across disciplinary boundaries. In this essay we propose a novel guiding framework for bringing colleagues together to advance knowledge and its integration across disciplines, the "Five 'C's' of Collaboration: Commitment, Collegiality, Communication, Consensus, and Continuity." This guiding framework for professional network practice is informed by both relevant literature and empirical evidence from community-building experience within the RCN-UBE Advancing Competencies in Experimentation-Biology (ACE-Bio) Network. The framework is presented with practical examples to illustrate how it might be used to enhance collaboration between new and existing participants in the ACE-Bio Network as well as within other interdisciplinary networks.

Biogeography of Alaska paper birch (Betula neoalaskana): latitudinal patterns in chemical defense and plant architecture.

The latitudinal herbivory-defense hypothesis (LHDH) predicts that plants near the equator will be more heavily defended against herbivores than are plants at higher latitudes. Although this idea is widely found in the literature, recent studies have called this biogeographic pattern into question. We sought to evaluate the LHDH in a high-latitude terrestrial ecosystem where fire and mammalian herbivores may contribute to selection for higher levels of defensive chemistry. To address this objective, we collected seeds of Alaska paper birch (Betula neoalaskana) from nine locations along two north-south transects between 55 degrees N and 62 degrees N latitudes in western, interior Canada. The birch seeds were planted in pots in a common garden in Madison, Wisconsin, USA. From the resulting seedlings, we determined levels of chemical defense by assessing the density of resin glands, which have been shown to be negatively correlated with browsing. To assess plant architectural traits such as height, mean individual leaf area, and root-to-shoot ratio, we harvested a subset of the birch seedlings. Further, we used these traits to examine growth-defense trade-offs. Contrary to the LHDH, we found a positive correlation between chemical defense and latitude. Investigating relationships with fire, we found a strong positive correlation between resin gland density and percentage of area annually burned (PAAB) around each collection location and also between PAAB and latitude. Additionally, birch seedlings originating from higher latitudes were shorter, smaller-leaved, and rootier than their lower-latitude counterparts. Growth-defense trade-offs were observed in negative correlations between resin gland density and height and leaf size. Seedlings with higher resin gland densities also allocated less biomass to shoots and more to roots. These results further call into question the LHDH and provide specific information about latitudinal trends in plant defense at high, northern latitudes where fire is a major ecosystem driver and mammals are the main herbivores of deciduous trees such as birches. We propose that these interconnected relationships are the key drivers of the positive correlation between defense and latitude in B. neoalaskana. Understanding patterns of boreal plant defense and growth is especially important because high latitude ecosystems are particularly susceptible to climate change. Key words: Alaska paper birch; Betula neoalaskana; biogeography; chemical defense; grotvth-defense trade-offs; inherent growth rate; latitude; latitudinal herbivory-defense hypothesis; papyr'feric acid; plant ar- chitecture; resin glands; root-to-shoot ratio.

Fostering Change from Within: Influencing Teaching Practices of Departmental Colleagues by Science Faculty with Education Specialties.

Globally, calls for the improvement of science education are frequent and fervent. In parallel, the phenomenon of having Science Faculty with Education Specialties (SFES) within science departments appears to have grown in recent decades. In the context of an interview study of a randomized, stratified sample of SFES from across the United States, we discovered that most SFES interviewed (82%) perceived having professional impacts in the realm of improving undergraduate science education, more so than in research in science education or K-12 science education. While SFES reported a rich variety of efforts towards improving undergraduate science education, the most prevalent reported impact by far was influencing the teaching practices of their departmental colleagues. Since college and university science faculty continue to be hired with little to no training in effective science teaching, the seeding of science departments with science education specialists holds promise for fostering change in science education from within biology, chemistry, geoscience, and physics departments.

Heterozygosity, gender, and the growth-defense trade-off in quaking aspen.

Although plant growth is generally recognized to be influenced by allocation to defense, genetic background (e.g., inbreeding), and gender, rarely have those factors been addressed collectively. In quaking aspen (Populus tremuloides Michx.), phenolic glycosides (PGs) and condensed tannins (CTs) constitute up to 30 % of leaf dry weight. To quantify the allocation cost of this chemical defense, we measured growth, defense chemistry, and individual heterozygosity (H obs at 16 microsatellite loci) for male and female trees in both controlled and natural environments. The controlled environment consisted of 12 juvenile genets grown for 3 years in a common garden, with replication. The natural environment consisted of 51 mature genets in wild populations, from which we sampled multiple ramets (trees) per genet. Concentrations of PGs and CTs were negatively correlated. PGs were uncorrelated with growth, but CT production represented a major cost. Across the range of CT levels found in wild-grown trees, growth rates varied by 2.6-fold, such that a 10 % increase in CT concentration occurred with a 38.5 % decrease in growth. H obs had a marked effect on aspen growth: for wild trees, a 10 % increase in H obs corresponded to a 12.5 % increase in growth. In wild trees, this CT effect was significant only in females, in which reproduction seems to exacerbate the cost of defense, while the H obs effect was significant only in males. Despite the lower growth rate of low-H obs trees, their higher CT levels may improve survival, which could account for the deficit of heterozygotes repeatedly found in natural aspen populations.

Long-term use of a 4% sodium cromoglicate cutaneous emulsion in the treatment of moderate to severe atopic dermatitis in children.

INTRODUCTION: Sodium cromoglicate (SCG), a chromone with anti-inflammatory, anti-itch and anti-allergic properties. We report a long-term study of a 4% aqueous solution of SCG in children with moderate to severe atopic dermatitis (AD). MATERIALS AND METHODS: Children aged 1 to 12 years with AD were entered into a 12-week randomised clinical trial (RCT), followed by 12 months open treatment with known 4% SCG emulsion (Altocrom®). Primary endpoint was change in SCORAD score. Secondary endpoints included symptom severity, Quality of Life, concomitant treatment usage, global assessments. RESULTS: One hundred and seventy-seven subjects entered, 118 treated with 4% SCG emulsion and 59 with vehicle: 128 completed 12 months in open study. SCORAD score reduced during RCT by -15.3 (-33%) on 4% SCG emulsion and -18.0 (-39%) on vehicle: p = 0.2331. After 12 months reduction was 56%. No secondary endpoint showed differences between treatments during RCT. Thirty-two subjects reported treatment related events during RCT and open trial. Eleven (7%) reported application site discomfort. Most were reported as mild and most resolved without intervention and the study drug was stopped in one case only. CONCLUSIONS: SCG 4% cutaneous emulsion was well tolerated in children treated for 15 months.

A randomised, controlled trial of a 4% cutaneous emulsion of sodium cromoglicate in treatment of atopic dermatitis in children.

INTRODUCTION: Atopic dermatitis (AD) is a chronic inflammatory skin disease. Sodium cromoglicate (SCG) is a chromone with anti-inflammatory, anti-itch and anti-allergic activity. This trial is a 12-week comparison (RCT) of a 4% SCG cutaneous emulsion with its vehicle in AD. MATERIALS AND METHODS: 208 children aged 2-12 years participated, 104 in each group. The primary endpoint was change in SCORAD score. Secondary endpoints included SASSAD score, topical steroid usage and global assessments. RESULTS: SCORAD was reduced by 28% (SCG group) and by 19% (vehicle): difference was statistically significant (p = 0.03) after 8 weeks and nearly significant (p = 0.09) after 12. A similar result occurred in SASSAD (p = 0.001 at 8 weeks). In subjects without major protocol deviations (SCG-64, vehicle-63), difference in SCORAD remained significant at 12 weeks (p = 0.04). Weight of topical steroids reduced in both groups: -0.60 ± 1.3 g/day (35%), SCG and -0.05 ± 1.1 g/day vehicle (p = 0.04). Treatment success, defined as investigator global opinion graded very or moderately effective, was significantly more frequent in SCG group (p = 0.025). Application site discomfort reported by 12.5% of subjects in SCG group and 16.5% in vehicle group. CONCLUSIONS: SCG 4% cutaneous emulsion provides an effective, well-tolerated, steroid-sparing treatment for AD in children.

The effect of 4% sodium cromoglicate cutaneous emulsion compared to vehicle in atopic dermatitis in children--A meta-analysis of total SCORAD scores.

An emulsion containing 4% sodium cromoglicate (4% SCG emulsion) has been developed for the treatment of atopic dermatitis in children. We have conducted a meta-analysis of the primary outcome measure (the change in SCORAD score) used in randomized clinical trials (RCTs) with this product. We conducted a search of standard using the keywords, sodium cromoglicate, cromolyn sodium, topical, atopic dermatitis, clinical trial. We identified 19 clinical studies of which 3 used this 4% SCG emulsion formulation, one was a RCT using the change in SCORAD score. We were given access to two further unpublished RCTs, with this measure. The RCTs included 490 subjects (mean age 5.3 years). Each RCT was multicentre of 12 weeks duration, comparing 4% SCG emulsion with the vehicle in which the SCG was dissolved. Using study as the unit and the fixed effect model, the mean difference (95% CI) in the change in SCORAD score was -2.82 (-5.36; -0.29), p = 0.03. Using centre as the unit, and the fixed effect model, the mean difference (95% CI) in the change in SCORAD score was -2.82 (-5.82; -0.46), p = 0.02. These results support the efficacy of this new topical treatment in children with atopic dermatitis.

Root chemistry in Populus tremuloides: effects of soil nutrients, defoliation, and genotype.

Although genetic, environmental, and G x E effects on aboveground phytochemistry have been well documented in trembling aspen (Populus tremuloides), little work has focused on the same factors affecting tissues underground. Belowground plant defenses are likely important mediators of root-feeding herbivores that can strongly influence plant fitness. We used a common garden of potted aspen trees to explore the individual and interactive effects of soil nutrient availability, foliar damage, genotype, and their interactions, on concentrations of phytochemicals in aspen roots. Our common garden experiment employed 12 aspen genotypes that were planted into either low- or high-nutrient soil environments. Half of the trees were subjected to defoliation for two successive years, while the others were protected from damage. At the end of the growing season after the second defoliation, we harvested the trees to obtain root samples for which we assessed levels of phenolic glycosides, condensed tannins, nitrogen, and starch. Phenolic glycosides were most affected by genotype, while the other root phytochemicals were most responsive to soil nutrient conditions. The effects of defoliation were observed in interaction with soil nutrient environment and/or genotype. Interestingly, the effect of defoliation on phenolic glycosides was mediated by soil nutrients, whereas the effect of defoliation on condensed tannins was observed in concert with effects of both soil nutrients and genotype. Comparison of data from this study with an earlier, related study revealed that concentrations of phenolic glycosides and condensed tannins are lower in roots than leaves, and less responsive to defoliation. That soil nutrient environment affects root phytochemical concentrations is not unexpected given the intimate association of roots and soil, but the complex interactions between soil nutrients, aboveground damage, and genotype, and their effects on root phytochemistry, are intriguing. Variation in root chemistry could have wide-reaching effects on soil microbial communities, nutrient cycling, and herbivores. Additionally, the response of phytochemicals to damage across organs can link different, spatially separated herbivores as they use different parts of the same plant resource.

Widespread distribution and unexpected variation among science faculty with education specialties (SFES) across the United States.

College and university science departments are increasingly taking an active role in improving science education. Perhaps as a result, a new type of specialized science faculty position within science departments is emerging--referred to here as science faculty with education specialties (SFES)--where individual scientists focus their professional efforts on strengthening undergraduate science education, improving kindergarten-through-12th grade science education, and conducting discipline-based education research. Numerous assertions, assumptions, and questions about SFES exist, yet no national studies have been published. Here, we present findings from a large-scale study of US SFES, who are widespread and increasing in numbers. Contrary to many assumptions, SFES were indeed found across the nation, across science disciplines, and, most notably, across primarily undergraduate, master of science-granting, and PhD-granting institutions. Data also reveal unexpected variations among SFES by institution type. Among respondents, SFES at master of science-granting institutions were almost twice as likely to have formal training in science education compared with other SFES. In addition, SFES at PhD-granting institutions were much more likely to have obtained science education funding. Surprisingly, formal training in science education provided no advantage in obtaining science education funding. Our findings show that the SFES phenomenon is likely more complex and diverse than anticipated, with differences being more evident across institution types than across science disciplines. These findings raise questions about the origins of differences among SFES and are useful to science departments interested in hiring SFES, scientific trainees preparing for SFES careers, and agencies awarding science education funding.

Genotypic differences and prior defoliation affect re-growth and phytochemistry after coppicing in Populus tremuloides.

Although considerable research has explored how tree growth and defense can be influenced by genotype, the biotic environment, and their interaction, little is known about how genotypic differences, prior defoliation, and their interactive effects persist in trees that re-grow after damage that severs their primary stem. To address these issues, we established a common garden consisting of twelve genotypes of potted aspen (Populus tremuloides) trees, and subjected half of the trees to defoliation in two successive years. At the beginning of the third year, all trees were severed at the soil surface (coppiced) and allowed to regenerate for five months. Afterwards, we counted the number of root and stump sprouts produced and measured the basal diameter (d) and height (h) of the tallest ramet in each pot. We collected leaves one and two years after the second defoliation and assessed levels of phenolic glycosides, condensed tannins, and nitrogen. In terms of re-growth, we found that the total number of sprouts produced varied by 3.6-fold among genotypes, and that prior defoliation decreased total sprout production by 24%. The size (d(2)h) of ramets, however, did not differ significantly among genotypes or defoliation classes. In terms of phytochemistry, we observed genotypic differences in concentrations of all phytochemicals assessed both one and two years after the second defoliation. Two years after defoliation, we observed effects of prior defoliation in a genotype-by-defoliation interaction for condensed tannins. Results from this study demonstrate that genotypic differences and impacts of prior defoliation persist to influence growth and defense traits in trees even after complete removal of above-ground stems, and thus likely influence productivity and plant-herbivore interactions in forests affected by natural disturbances or actively managed through coppicing.

The effects of topical sodium cromoglicate on itch and flare in human skin induced by intradermal histamine: a randomised double-blind vehicle controlled intra-subject design trial.

BACKGROUND: Itch is a prominent feature of many skin diseases, particularly atopic dermatitis and cutaneous mastocytosis. Sodium cromoglicate (SCG), a chromone developed for the treatment of allergic disease has been shown to reduce the severity of itch when applied topically to subjects with atopic dermatitis. The aim of this study was to investigate whether topical sodium cromoglicate can reduce the severity of itch induced by intradermal histamine. METHODS: SCG was introduced into the skin of healthy volunteers both by iontophoresis and by topical application using a new 4% cutaneous emulsion (Altoderm™). The skin was then challenged with intradermal histamine. Measurements were made of severity of itch, size of wheal and flare and change in blood flux RESULTS: SCG significantly reduced the severity of itch (P = 0.0045) and flare (P = 0.0143) when delivered by iontophoresis. SCG 4% cutaneous emulsion significantly reduced severity of itch (P = 0.024) and flare (P = 0.015) in atopic subjects. Trend analysis showed increasing effect on itch with increased concentrations of SCG, which was significant (P = 0.046). There were no effects on wheal or blood flux. CONCLUSIONS: Topically applied SCG, administered in a new cutaneous emulsion base, significantly reduced the itch and flare caused by intradermal histamine. The effect was greatest in atopic subjects and increased with the concentration of SCG in the emulsion. TRIAL REGISTRATION: ISRCTN35671014.

Investigation of science faculty with education specialties within the largest university system in the United States.

Efforts to improve science education include university science departments hiring Science Faculty with Education Specialties (SFES), scientists who take on specialized roles in science education within their discipline. Although these positions have existed for decades and may be growing more common, few reports have investigated the SFES approach to improving science education. We present comprehensive data on the SFES in the California State University (CSU) system, the largest university system in the United States. We found that CSU SFES were engaged in three key arenas including K-12 science education, undergraduate science education, and discipline-based science education research. As such, CSU SFES appeared to be well-positioned to have an impact on science education from within science departments. However, there appeared to be a lack of clarity and agreement about the purpose of these SFES positions. In addition, formal training in science education among CSU SFES was limited. Although over 75% of CSU SFES were fulfilled by their teaching, scholarship, and service, our results revealed that almost 40% of CSU SFES were seriously considering leaving their positions. Our data suggest that science departments would likely benefit from explicit discussions about the role of SFES and strategies for supporting their professional activities.

Fire drives transcontinental variation in tree birch defense against browsing by snowshoe hares.

Fire has been the dominant disturbance in boreal America since the Pleistocene, resulting in a spatial mosaic in which the most fire occurs in the continental northwest. Spatial variation in snowshoe hare (Lepus americanus) density reflects the fire mosaic. Because fire initiates secondary forest succession, a fire mosaic creates variation in the abundance of early successional plants that snowshoe hares eat in winter, leading to geographic variation in hare density. We hypothesize that fire is the template for a geographic mosaic of natural selection: where fire is greatest and hares are most abundant, hare browsing has most strongly selected juvenile-phase woody plants for defense. We tested the hypothesis at multiple spatial scales using Alaska birch (Betula neoalaskana) and white birch (Betula papyrifera). We also examined five alternative hypotheses for geographic variation in antibrowsing defense. The fire-hare-defense hypothesis was supported at transcontinental, regional, and local scales; alternative hypotheses were rejected. Our results link transcontinental variation in species interactions to an abiotic environmental driver, fire. Intakes of defense toxins by Alaskan hares exceed those by Wisconsin hares, suggesting that the proposed selection mosaic may coincide with a geographic mosaic of coevolution.

Extrafloral nectaries in aspen (Populus tremuloides): heritable genetic variation and herbivore-induced expression.

BACKGROUND AND AIMS: A wide variety of plants produce extrafloral nectaries (EFNs) that are visited by predatory arthropods. But very few studies have investigated the relationship between plant genetic variation and EFNs. The presence of foliar EFNs is highly variable among different aspen (Populus tremuloides) genotypes and the EFNs are visited by parasitic wasps and predatory flies. The aim here was to determine the heritability of EFNs among aspen genotypes and age classes, possible trade-offs between direct and indirect defences, EFN induction following herbivory, and the relationship between EFNs and predatory insects. METHODS: EFN density was quantified among aspen genotypes in Wisconsin on trees of different ages and broad-sense heritability from common garden trees was calculated. EFNs were also quantified in natural aspen stands in Utah. From the common garden trees foliar defensive chemical levels were quantified to evaluate their relationship with EFN density. A defoliation experiment was performed to determine if EFNs can be induced in response to herbivory. Finally, predatory arthropod abundance among aspen trees was quantified to determine the relationship between arthropod abundance and EFNs. KEY RESULTS: Broad-sense heritability for expression (0.74-0.82) and induction (0.85) of EFNs was high. One-year-old trees had 20% greater EFN density than 4-year-old trees and more than 50% greater EFN density than > or =10-year-old trees. No trade-offs were found between foliar chemical concentrations and EFN density. Predatory fly abundance varied among aspen genotypes, but predatory arthropod abundance and average EFN density were not related. CONCLUSIONS: Aspen extrafloral nectaries are strongly genetically determined and have the potential to respond rapidly to evolutionary forces. The pattern of EFN expression among different age classes of trees appears to follow predictions of optimal defence theory. The relationship between EFNs and predators likely varies in relation to multiple temporal and environmental factors.

Browse quality in quaking Aspen (Populus tremuloides): effects of genotype, nutrients, defoliation, and coppicing.

The consequences of interactions among genetic, ontogenetic, and environmental factors for the quality of winter-dormant tissues as food for browsing herbivores is poorly understood. We conducted two sequential common garden studies to assess the impacts of intraspecific genetic variation, nutrient availability, prior defoliation, and ontogenetic stage on the chemical quality of winter-dormant tissue in quaking aspen (Populus tremuloides Michx.). In the first study, saplings of 12 aspen genotypes were grown under low and high soil nutrient conditions, with or without two successive seasons of defoliation. Quantity and quality of current year's twig growth were assessed. Twig production varied among genotypes and declined under low nutrient availability, but showed little response to prior defoliation. Chemical quality of sapling twigs varied substantially among genotypes, and in response to nutrient availability and prior defoliation. Overall, browse quality improved (nitrogen levels increased while phenolic glycoside and condensed tannin levels decreased) after defoliation. Growth and chemical variables exhibited low to moderate clonal repeatability (broad sense heritability) values. Our second study employed the same 12 genotypes, grown under high-nutrient conditions and with or without two seasons of defoliation. The trees were coppiced to produce root sprouts, which were chemically assessed 1 yr later. Rejuvenation via coppicing led to increased levels of nitrogen, phenolic glycosides (salicortin), and tannins in root sprouts, and the magnitude of change varied among aspen genotypes. Signatures of defoliation nearly 2 yr earlier persisted in terms of elevated levels of phenolic glycosides in root sprouts of previously defoliated trees. Aspen forests likely present browsing herbivores with chemically heterogeneous environments because of the interactions of genetic, ontogenetic, and environmental factors that vary over space and time.