White Oak Research Articles

Seasonal variations of leaf ecophysiological traits and strategies of co-occurring evergreen and deciduous trees in white oak forest in the central Himalaya.

The present study investigates the seasonal variations in leaf ecophysiological traits and strategies employed by co-occurring evergreen and deciduous tree species within a white oak forest (Quercus leucotrichophora A. Camus) ecosystem in the central Himalaya. Seasonal variations in physiological, morphological, and chemical traits were observed from leaf initiation until senescence in co-occurring deciduous and evergreen tree species. We compared various parameters, including net photosynthetic capacity (Aarea and Amass), leaf stomatal conductance (gswarea and gswmass), transpiration rate (Earea and Emass), specific leaf area (SLA), mid-day water potential (Ψmd), leaf nitrogen (N) and phosphorus (P) concentration, leaf total chlorophyll concentration, photosynthetic nitrogen- and phosphorus-use efficiency (PNUE and PPUE), and water use efficiency (WUE) across four evergreen and four deciduous tree species. Our findings reveal that evergreen and deciduous trees exhibit divergent strategies in coping with seasonal changes, which are crucial for their survival and growth. Deciduous trees consistently exhibited significantly higher photosynthetic rates, transpiration rates, mass-based N and P concentrations (Nmass and Pmass), mass-based chlorophyll concentration (Chlmass), SLA, and leaf Ψmd, while maintaining lower leaf structural investments throughout the year compared to evergreen trees. These findings indicate that deciduous trees achieve greater assimilation rates per unit mass and higher nutrient-use efficiency. Physiological, morphological, and leaf N and P concentrations were higher in the summer (fully expanded leaf) than in the fall (senesced leaf). These insights provide valuable contributions to our understanding of tree species coexistence and their ecological roles in temperate forest ecosystems, with implications for forest management and conservation in the Himalayan region.

Дендроэкологическое исследование роста осины в условиях Московской области

According to V.A. Dragavtsev's concept, the reaction of the annual ring to the provocative environmental background of different years creates a “portrait” of adaptive polygenic genotype systems. By comparing the reactions of the main forest-forming species from an ecologically homogeneous habitat, it is possible to assess the level of similarity of their ecological properties. Cluster analysis of tree-ring chronologies of aspen and species growing together with it, correlation analysis of chronologies and indexed chronologies, as well as time series of meteorological factors and Fourier spectral analysis have been used for a dendroecological research into aspen growth features in the conditions of the Molokchinskiy Botanical and Entomological Reserve of the Sergiev Posad District of the Moscow Region. To compare with the chronologies of aspen from two stands, the chronologies of European white birch, English oak, grey alder and Norway spruce have been used. It has been established that the cluster analysis of indexed chronologies based on calculating the squared Euclidean distance and combining the chronologies into groups according to the rule of complete linkage distinguishes aspen chronologies into a separate cluster, very distant from the other species under consideration. According to the correlation analysis of indexed chronologies, the dynamics of radial increment of aspen is most closely related to the dynamics of radial increment of European white birch and gray alder. Moreover, the maximum correlation coefficient (0.71) is observed for the chronologies of aspen from two different stands. Among the climatic factors, the main limiting influence on aspen increment is exerted by July precipitation in the year of the annual ring formation and August precipitation in the year preceding the year of the annual ring formation. The response to precipitation in August last year is specific to aspen stands and has several options for ecophysiological interpretation. According to Fourier spectral analysis, aspen chronologies have the most pronounced cyclic component with a period of 10.4 years, which completely coincides with the cyclic component of the time series of Wolf numbers in the time interval under consideration. This distinguishes aspen from the rest of the studied forest-forming species. A conclusion has been made about the specificity of the dynamics of the radial growth of aspen in comparison with other forest-forming species under study.

Whole-genome screening for near-diagnostic genetic markers for four western European white oak species identification

Key messageMining genome-wide DNA sequences enabled the discovery of near-diagnostic markers for species assignment in four European white oaks (Quercus petraea (Matt.) Liebl., Quercus pubescens Willd., Quercus pyrenaica Willd., and Quercus robur L.) despite their low interspecific differentiation. Near-diagnostic markers are almost fully fixed in one species and absent in the three others. As a result, only a handful of markers are needed for species identification, making this genetic assay a very promising operational taxonomic assignment procedure in research and forestry.ContextIdentifying species in the European white oak complex has been a long-standing concern in taxonomy, evolution, forest research, and management. Quercus petraea (Matt.) Liebl., Q. robur L., Q. pubescens Willd., and Q. pyrenaica Willd. are part of this species complex in western temperate Europe and hybridize in mixed stands, challenging species identification.AimsOur aim was to identify near-diagnostic single-nucleotide polymorphisms (SNPs) for each of the four species that are suitable for routine use and rapid diagnosis in research and applied forestry.MethodsWe first scanned existing whole-genome and target-capture data sets in a reduced number of samples (training set) to identify candidate diagnostic SNPs, i.e., genomic positions being characterized by a reference allele in one species and by the alternative allele in all other species. Allele frequencies of the candidates SNPs were then explored in a larger, range-wide sample of populations in each species (validation step).ResultsWe found a subset of 38 SNPs (10 for Q. petraea, 7 for Q. pubescens, 9 for Q. pyrenaica, and 12 for Q. robur) that showed near-diagnostic features across their species distribution ranges with Q. pyrenaica and Q. pubescens exhibiting the highest (0.876) and lowest (0.747) diagnosticity, respectively.ConclusionsWe provide a new, efficient, and reliable molecular tool for the identification of the species Q. petraea, Q. robur, Q. pubescens, and Q. pyrenaica, which can be used as a routine tool in forest research and management. This study highlights the resolution offered by whole-genome sequencing data to design near-diagnostic marker sets for taxonomic assignment, even for species complexes with relatively low differentiation.

Chloroplast Haplotype Diversity in the White Oak Populations of the Italian Peninsula, Sicily, and Sardinia

A phylogeographic study on the chloroplast DNA of natural white oak forests (Quercus subgen. Quercus, sect. Quercus) was carried out to identify possible haplotype-structured distribution within the Italian Peninsula, Sicily, and Sardinia. Sixty white oak populations belonging to Q. frainetto, Q. robur and the collective groups Q. petraea and Q. pubescens were considered and analyzed by combining five Chloroplast Simple Sequence Repeat (cpSSR) markers. A total of 28 haplotypes were detected. Central and southern Italy displayed the highest variability (14 and 10 haplotypes, respectively), followed by northern Italy (7), Sardinia (7), and Sicily (5). A complex geographical structure of the haplotype distribution emerged, highlighting (i) a high number of low-frequency haplotypes; (ii) the marked isolation of Sardinia; (iii) the occurrence of haplotypes widely distributed throughout the Italian Peninsula; (iv) the idiosyncrasy of Sicily, which exhibits exclusive haplotypes, and haplotypes shared with Sardinia and the rest of the Italian Peninsula. The haplotype distribution was also found to be partially related to the taxonomic identity of the specimens, with the following features emerging: a geographic separation between the central Italy and southern Italy Q. frainetto populations, an unexpected discontinuity between the Calabrian and Sicilian Q. petraea subsp. austrotyrrhenica populations, and the absence of the most common haplotype among the Q. pubescens populations of central and southern Italy.

Use of lower tolerance limits for designing chair frames with round-end mortise and tenon joints

ABSTRACT In this study, the reliability of the mortise-tenon (MT) joints was examined experimentally and numerically. The joint strength has been determined empirically and numerically, but the reliability of the joint does not rely on a single asset – mean and standard deviation. The prediction of its strength also refers to a single value in the future population, but tolerance limits are related to a portion of the future population. Therefore, ensuring joint reliability comes into prominence not only for empirical data but also for theoretical and numerical analysis. For this purpose, the moment capacity of the T-shaped MT joints constructed of white oak was determined, and the lower tolerance limits (LTLs) approach was used to construct confidence/proportion (γ/β) levels for reliability. According to the results, the moment capacity of the MT joints was 341 Nm. The LTL values at 0.95/0.95, 0.99/0.95, 0.95/0.99, and 0.99/0.99 γ/β levels were 231, 226, 187 and 181 Nm, respectively. The normal stresses at each γ/β level were calculated based on the moment capacity and tenon sizes and were compared with the finite element method (FEM). Experimental and numerical results varied from 0.3% to 13.4%. Furthermore, a side frame was imposed to a vertical load of 1000 N on the front leg, and the moment of the joint on the side rail to the back post was measured (196 Nm). The side frame was modeled on ABAQUS – FEM software – and subjected to a moment of 196 Nm on the side rail. The theoretical and numerical results of stresses on joints differed from – 4.3% to 5.8%. The study showed that the reliability value is known, and; the joints could be designed by using FEM.

Association of serum total IgE and allergen-specific IgE with insulin resistance in adolescents: an analysis of the NHANES database

BackgroundRecent studies have found that total immunoglobulin E (IgE) and allergen-specific IgE were associated with some metabolic diseases. However, the role of IgE in metabolism among adolescents is still unclear. Herein, this study aims to investigate the associations of serum total IgE and allergen-specific IgE with insulin resistance (IR) in adolescents, in order to provide some reference for the prevention and treatment of metabolic diseases in a young age.MethodsData of 870 adolescents were extracted from the National Health and Nutrition Examination Survey (NHANES) database in 2005–2006 in this cross-sectional study. Weighted univariate and multivariate logistic regression analyses were utilized to screen covariates and explore the relationships of serum total IgE and allergen-specific IgE with IR. The evaluation indexes were odds ratios (ORs) and 95% confidence intervals (CIs). In addition, these relationships were also assessed in subgroups of allergy history, asthma history, and number of allergens.ResultsAmong eligible adolescents, 168 had IR. No significant association between serum total IgE level and IR was found. However, adolescents with higher level of allergen-specific IgE to rye grass [OR = 0.47, 95%CI: (0.25–0.91)], white oak [OR = 0.57, 95%CI: (0.37–0.88)], or peanut [OR = 0.38, 95%CI: (0.15–0.97)] seemed to have lower odds of IR, whereas those had higher level of shrimp-specific IgE [OR = 2.65, 95%CI: (1.21–5.84)] have increased odds of IR. In addition, these associations between allergen-specific IgE and IR were also discovered in adolescents who had allergy history or asthma history, or had different numbers of allergens.ConclusionPaying attention to different allergens in adolescents may be important in the early identification of IR among this high-risk population. The study results relatively provided some reference for further exploration on IR prevention.

CentralBark Image Dataset and Tree Species Classification Using Deep Learning

The task of tree species classification through deep learning has been challenging for the forestry community, and the lack of standardized datasets has hindered further progress. Our work presents a solution in the form of a large bark image dataset called CentralBark, which enhances the deep learning-based tree species classification. Additionally, we have laid out an efficient and repeatable data collection protocol to assist future works in an organized manner. The dataset contains images of 25 central hardwood and Appalachian region tree species, with over 19,000 images of varying diameters, light, and moisture conditions. We tested 25 species: elm, oak, American basswood, American beech, American elm, American sycamore, bitternut hickory, black cherry, black locust, black oak, black walnut, eastern cottonwood, hackberry, honey locust, northern red oak, Ohio buckeye, Osage-orange, pignut hickory, sassafras, shagbark hickory silver maple, slippery elm, sugar maple, sweetgum, white ash, white oak, and yellow poplar. Our experiment involved testing three different models to assess the feasibility of species classification using unaltered and uncropped images during the species-classification training process. We achieved an overall accuracy of 83.21% using the EfficientNet-b3 model, which was the best of the three models (EfficientNet-b3, ResNet-50, and MobileNet-V3-small), and an average accuracy of 80.23%.

Urbanization exacerbates climate sensitivity of eastern United States broadleaf trees.

Tree growth is a key mechanism driving carbon sequestration in forest ecosystems. Environmental conditions are important regulators of tree growth that can vary considerably between nearby urban and rural forests. For example, trees growing in cities often experience hotter and drier conditions than their rural counterparts while also being exposed to higher levels of light, pollution, and nutrient inputs. However, the extent to which these intrinsic differences in the growing conditions of trees in urban versus rural forests influence tree growth response to climate is not well known. In this study, we tested for differences in the climate sensitivity of tree growth between urban and rural forests along a latitudinal transect in the eastern United States that included Boston, Massachusetts, New York City, New York, and Baltimore, Maryland. Using dendrochronology analyses of tree cores from 55 white oak trees (Quercus alba), 55 red maple trees (Acer rubrum), and 41 red oak trees (Quercus rubra) we investigated the impacts of heat stress and water stress on the radial growth of individual trees. Across our three-city study, we found that tree growth was more closely correlated with climate stress in the cooler climate cities of Boston and New York than in Baltimore. Furthermore, heat stress was a significant hindrance to tree growth in higher latitudes while the impacts of water stress appeared to be more evenly distributed across latitudes. We also found that the growth of oak trees, but not red maple trees, in the urban sites of Boston and New York City was more adversely impacted by heat stress than their rural counterparts, but we did not see these urban-rural differences in Maryland. Trees provide a wide range of important ecosystem services and increasing tree canopy cover was typically an important component of urban sustainability strategies. In light of our findings that urbanization can influence how tree growth responds to a warming climate, we suggest that municipalities consider these interactions when developing their tree-planting palettes and when estimating the capacity of urban forests to contribute to broader sustainability goals in the future.

Finding the last missing white oak hybrid from the Iberian Peninsula (Fagaceae, Quercus, sect. Quercus)

The genus Quercus is widely known for its ability to hybridize among sympatric species, especially inside the same Section. The Iberian Peninsula is a major phylogeographic hotspot for oak diversity, with almost all possible combinations of hybrids already described inside sect. Quercus. In this work we present the remaining hybrid not yet described among the Iberian white oaks; we found it in one of the few areas (in the Southern Iberian Peninsula) where both parents (the Algerian oak, Q. canariensis, and the Lusitanian dwarf oak, Q. lusitanica) grow sympatrically. We provide a description of this nothotaxon (which we named Quercus ×gaonae) based on morphological characters related to leaf shape and trichome analysis. This work emphasizes the practice of natural history and encourages botanists to keep up their work on describing plant diversity in a major hotspot like the Mediterranean Basin.

Climate Adaptation in White Oak (Quercus alba, L.): A Forty-Year Study of Growth and Phenology

Climate change poses a significant threat to the resilience and sustainability of forest ecosystems. This study examines the performance of white oak (Quercus alba, L.) across a range of provenances in a common garden planting, focusing on the species’ response to climatic variables and the potential role of assisted migration in forest management. We evaluated the survival and growth rates of white oak provenances originating from various points along a latitudinal gradient over a period of 40 years. These provenances were planted in a common garden situated near the midpoint of this latitudinal gradient, where we also monitored their phenological traits, such as budburst and leaf senescence. The results revealed substantial variation in phenological responses and growth patterns among the provenances, with southern provenances demonstrating faster growth and later senescence relative to local sources, with limited impact on survival. In contrast, the northern provenances demonstrated slower growth, resulting in later-aged competition-induced mortality. The findings highlight the necessity of incorporating genetic diversity into white oak reforestation and conservation strategies, as the local provenance may no longer be the most suitable option for current and future conditions. We advocate for a nuanced approach to forest management that leverages genetic insights to optimize seed source selection for reforestation, fostering resilient forest landscapes in the face of ongoing climate shifts.

Continued response of Oregon oak to release treatments 20 years after initiation in western Washington, United States

Fire suppression has increased competitive tree encroachment of Oregon white oak (Quercus garryanna Douglas ex Hook) ecosystems, threatening maintenance of this important species. Restoration of oak ecosystems is ideal to address this threat but not always possible, giving rise to a need for novel treatments that will allow oak to persist on an altered landscape. We tested the effect of three release treatments centered around individual Oregon oak trees within four forested sites that had developed following encroachment and overtopping by Douglas‐fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii). The release treatments entailed removal of competitive tree species (>10 cm dimaeter at breast heigh [DBH]) within zero (as control), half, or full distance of the associated Oregon oak trees' height. There was no effect of release treatment on height, but diameter was significantly increased in the full release treatment relative to both the control and half release treatments. The effect on diameter increased up to year 10 and then decreased to year 20. Growth response to canopy damage from an ice storm in year 12 of the study varied significantly with treatment; growth was negatively related to the percent crown damage in both release treatments but not the control treatment. Full release treatments around individual Oregon oak trees can have long‐term positive effects on growth, providing managers with an option to maintain oak within altered ecosystems.

Divergence and reticulation in the Mexican white oaks: ecological and phylogenomic evidence on species limits and phylogenetic networks in the Quercus laeta complex (Fagaceae).

Introgressive hybridization poses a challenge to taxonomic and phylogenetic understanding of taxa, particularly when there are high numbers of co-occurring, intercrossable species. The genus Quercus exemplifies this situation. Oaks are highly diverse in sympatry and cross freely, creating syngameons of interfertile species. Although a well-resolved, dated phylogeny is available for the American oak clade, evolutionary relationships within many of the more recently derived clades remain to be defined, particularly for the young and exceptionally diverse Mexican white oak clade. Here, we adopted an approach bridging micro- and macroevolutionary scales to resolve evolutionary relationships in a rapidly diversifying clade endemic to Mexico. Ecological data and sequences of 155 low-copy nuclear genes were used to identify distinct lineages within the Quercus laeta complex. Concatenated and coalescent approaches were used to assess the phylogenetic placement of these lineages relative to the Mexican white oak clade. Phylogenetic network methods were applied to evaluate the timing and genomic significance of recent or historical introgression among lineages. The Q. laeta complex comprises six well-supported lineages, each restricted geographically and with mostly divergent climatic niches. Species trees corroborated that the different lineages are more closely related to other species of Mexican white oaks than to each other, suggesting that this complex is polyphyletic. Phylogenetic networks estimated events of ancient introgression that involved the ancestors of three present-day Q. laeta lineages. The Q. laeta complex is a morphologically and ecologically related group of species rather than a clade. Currently, oak phylogenetics is at a turning point, at which it is necessary to integrate phylogenetics and ecology in broad regional samples to figure out species boundaries. Our study illuminates one of the more complicated of the Mexican white oak groups and lays groundwork for further taxonomic study.

First report of Diplodia quercivora causing branch cankers on declining chestnut oak (Quercus montana) in Virginia.

Since the beginning of the twentieth century oak decline has been documented in central and eastern hardwood forests of the United States as a stress-mediated disease (Oak et al. 2016). Opportunistic canker pathogens, including Diplodia corticola, D. quercivora, D. sapinea, and Botryosphaeria dothidea have been associated with crown dieback of declining oak trees in several mid-Atlantic states (Ferreira et al. 2021). On 02 August 2022, a survey was conducted at two natural hardwood sites in Fredrick and Shenandoah Counties, Virginia that exhibited symptoms of decline (Fig. 1A). At both sites, mature Quercus montana trees were observed with bole and branch cankers, bleeding and sooty lesions, and discolored sapwood. Pycnidia were present on the margin of seven branch cankers from three trees that were felled, with hyaline, elliptical to oblong conidia 19.0 - 26.8 × 8.5 - 11.2 µm (n = 40) in size (Fig. 1C and D). Six cultures were derived from single spores that were placed on PDA medium and incubated for 10 days in the dark at 22 ± 2°C. Additionally, a 4-mm piece of necrotic tissue was selected from the margin of each of the seven cankers, disinfected with 2.5% NaOCl, again with 70% ethanol, and air-dried before being placed on half-strength acidified PDA medium (pH 4.8) and incubated in the dark at 22 ± 2°C. After 5 days, seven colonies from each canker assayed were transferred to full-strength PDA plates and incubated for 10 days in the dark at 22 ± 2°C. Colonies derived from spores and the necrotic wood were morphologically identical, with white, aerial, floccose mycelium that turned dark gray to olivaceous after five days (Fig. 1B). DNA was individually extracted from four, 10-day-old cultures (two from spores and two from wood). Mycelia was harvested with a sterile pin and extracted using a Qiagen DNeasy Plant Pro Kit (Germantown, MD) according to the manufacturer's instructions. A segment of the internal transcribed spacer (ITS), large subunit rRNA (LSU), and translation elongation factor 1-α (tef1) loci were amplified using ITS4/ITS5 (White et al. 1990), LR5/LROR (Vilgalys and Hester 1990), and EF1-728F/EF1-986R (Carbone and Kohn 1999) primer sets, respectively. The PCR amplicons were purified with ExoSap-IT (Affymetrix, Santa Clara, CA) and sequenced at Eurofins (Louisville, KY). The nucleotide sequences were analyzed using Geneious 11.1.5 software (Biomatters, Auckland, NZ). The resulting ITS sequences from the four isolates were identical. A 544-bp, 1131-bp, and 273-bp segment of the ITS, LSU, and tef1 loci from isolate GS22-DSB-17 was deposited into the GenBank database (accessions OQ597712, OQ597714, and OR754429, respectively). A Genbank BLAST analysis revealed that the ITS and tef1 fragments shared 510/516 (99%) and 271/273 (99%) nucleotides with the D. quercivora ex-type BL8 (JX894205/JX894229). Koch's postulates were fulfilled by inoculating five healthy, containerized Q. montana trees (average stem caliper 6.5 cm) with D. qercivora isolate GS22-DSB-17, while five plants were used as controls. After disinfecting the bark with 70% ethanol, a 0.5 mm section of the bark was removed 13 cm above the soil line with a sterile scalpel, and a 0.5 mm agar plug taken from the edge of a 10-day-old PDA culture was placed in the wound with the mycelium facing the cambial tissue, sealed with Parafilm, and maintained at 22 ± 6°C. The same procedure was performed on the control plants using sterile PDA plugs. After six weeks the bark was carefully removed, and all five stems treated with D. quercivora had necrotic lesions with a mean canker linear growth ([length+width]/2) of 15.6 mm from the edge of the wound, which was significantly larger (P = 0.001) than the controls (2.3 mm; Fig. 1E-M). Necrotic stem tissue was sampled as previously described, and the isolate recovered was confirmed as D. quercivora based on morphology and 100% ITS sequence homology to isolate GS22-DSB-17. D. quercivora was not recovered from the control plants. In the United States, D. quercivora has been isolated from declining white oak trees in Maryland, Massachusetts, West Virginia, and Florida (Dreaden et al. 2014; Ferreira et al. 2021; Haines et al. 2019). More surveys are needed to understand the host range and distribution of D. quercivora in the United States, as well as the environmental and site factors that impact oak health and predispose trees to infection from opportunistic cankering pathogens.

Intraspecific genetic divergence of the subalpine shrubby variety Quercus crispula var. horikawae from the mountain tree variety Q. crispula var. crispula in Japan

AbstractEcotypic divergence in tree taxa often occurs in subalpine habitats, where environmental conditions are more stressful than those in lower elevations. In the white oak species in Japan Quercus crispula, the subalpine shrubby variety Q. crispula var. horikawae (Qch) has been recognized in central and northern Honshu. Although Qch has different phenotypes from Q. crispula var. crispula (Qcc), genetic divergence between Qcc and Qch has not been examined yet. Pairs of Qcc and Qch populations in eight locations and additional Qcc and Qch populations around these locations were investigated. Leaf size of Qch was smaller than that of Qcc. Chloroplast DNA haplotypes were shared between the Qcc and Qch populations. In genotypes at 29 nuclear microsatellite loci, genetic diversity did not differ between the Qcc and Qch populations. Principal component analysis and a neighbor‐joining tree of populations based on the genotypes demonstrated that 13 Qcc populations and eight Qch populations were grouped separately, except for three Qch populations that were grouped to Qcc. Climatic conditions in the eight Qch populations were characterized by lower temperature and heavier snowfall than those in the 16 populations of the genetic group of Qcc. These results suggest genetic divergence between Qcc and Qch associated with subalpine climatic conditions, irrespective of leaf size. The origin of the subalpine Qch lineage and the history of ecotypic divergence should be investigated in future genomic studies.

Characterizing spring phenology in a temperate deciduous urban woodland fragment: trees and shrubs.

Phenological research in temperate-deciduous forests typically focuses on upper canopy trees, due to their overwhelming influence on ecosystem productivity and function. However, considering that shrubs leaf out earlier and remain green longer than trees, they play a pivotal role in ecosystem productivity, particularly at growing season extremes. Furthermore, an extended growing season of non-native shrubs provides a competitive advantage over natives. Here, we report spring phenology, budburst, leaf-out, and full-leaf unfolded (2017-2021) of a range of co-occurring species of tree (ash, American basswood, red oak, white oak, and boxelder) and shrub (native species: chokecherry, pagoda dogwood, nannyberry, American wild currant and Eastern wahoo, and non-native species: buckthorn, honeysuckle, European privet, and European highbush cranberry) in an urban woodland fragment in Wisconsin, USA, to determine how phenology differed between plant groups. Our findings show that all three spring phenophases of shrubs were 3weeks earlier (p < 0.05) than trees. However, differences between shrubs groups were only significant for the later phenophase; full-leaf unfolded, which was 6days earlier (p < 0.05) for native shrubs. The duration of the spring phenological season was 2weeks longer (p < 0.05) for shrubs than trees. These preliminary findings demonstrate that native shrubs, at this site, start full-leaf development earlier than non-native species suggesting that species composition must be considered when generalizing whether phenologies differ between vegetation groups. A longer time series would be necessary to determine future implications on ecosystem phenology and productivity and how this might impact forests in the future, in terms of species composition, carbon sequestration, and overall ecosystem dynamics.

Will “Tall Oaks from Little Acorns Grow”? White Oak (Quercus alba) Biology in the Anthropocene

Quercus alba L., also known as white oak, eastern white oak, or American white oak, is a quintessential North American species within the white oak section (Quercus) of the genus Quercus, subgenus Quercus. This species plays a vital role as a keystone species in eastern North American forests and plays a significant role in local and regional economies. As a long-lived woody perennial covering an extensive natural range, Q. alba’s biology is shaped by a myriad of adaptations accumulated throughout its natural history. Populations of Q. alba are crucial repositories of genetic, genomic, and evolutionary insights, capturing the essence of successful historical adaptations and ongoing responses to contemporary environmental challenges in the Anthropocene. This intersection offers an exceptional opportunity to integrate genomic knowledge with the discovery of climate-relevant traits, advancing tree improvement, forest ecology, and forest management strategies. This review provides a comprehensive examination of the current understanding of Q. alba’s biology, considering past, present, and future research perspectives. It encompasses aspects such as distribution, phylogeny, population structure, key adaptive traits to cyclical environmental conditions (including water use, reproduction, propagation, and growth), as well as the species’ resilience to biotic and abiotic stressors. Additionally, this review highlights the state-of-the-art research resources available for the Quercus genus, including Q. alba, showcasing developments in genetics, genomics, biotechnology, and phenomics tools. This overview lays the groundwork for exploring and elucidating the principles of longevity in plants, positioning Q. alba as an emerging model tree species, ideally suited for investigating the biology of climate-relevant traits.

Japanese white oak seedlings killed by Phytophthora castaneae: a potential source of chestnut trunk rot

Japanese white oak seedlings killed by Phytophthora castaneae: a potential source of chestnut trunk rot

Structural performance of connectors in a hardwood stairway handrail guard system

Wood is a preferred material for constructing staircases due to its appealing aesthetic features. The use of wood, especially hardwoods such as red oak (Quercus rubra), white oak (Quercus alba), yellow poplar (Liriodendron tulipifera), and hard maple (Acer saccharum), has been the main construction material for staircases over the years. Staircase designs have evolved because of the flexibility of wood and working with specialized manufacturing machinery. A stair guard system connection must be designed to resist rotational and translational movements whenever a force is applied to the handrail. The demand for structural design values in wooden stair guards has been steadily increasing, driven by the needs of engineers, designers, builders, and end-users alike. This paper presents experimental data for four stair guard connections (post-to-rail, infill-to-footing, infill-to-rail, and rail-to-rail) encountered in a hardwood stairway handrail guard system. The data generated from this research could be useful for modeling the structural behavior of the connections.

Economic Impacts of Projected White Oak (Quercus alba L.) Timber Supply in Kentucky: A CGE Model Analysis

Demand for high-quality white oak sawlogs in Kentucky has been increasing for decades. Concurrently, Kentucky is witnessing ecological shifts in the historically white oak-dominated forests, mirroring the structural changes in oak forests in the eastern US. This demand–supply dissonance presents a growing concern among stakeholders on the sustainability of white oak and its associated economic implications. In this context, the objective of this study was to assess the potential economic impacts of the projected white oak timber supply following an overall increased supply of white oak sawlogs but reduced supply of high-quality white oak sawlogs in Kentucky. Results generated from a dynamic computable general equilibrium (CGE) model indicate a cumulative present-value GDP reduction of USD 3.66 billion, a USD 0.71 billion decline in consumer welfare, and other sectoral contractions over 40 years (2018–2058). These results can be used to advocate for more proactive forest management practices to stabilize a sustained supply of high-quality white oak timber in Kentucky and beyond.

Early silvicultural intervention affects species dominance in efforts to restore pine-hardwood mixedwoods following stand-replacing disturbance

Interest in replacing monocultures with species diverse stands has steadily grown. Mixedwoods (stands containing a balance of conifer and hardwood species) represent an alternative to monocultures and occur naturally through forest succession on most sites in eastern North America. In the central and southeastern United States, mixedwoods were generally dominated by pine and upland oak species. However, a combination of anthropogenic land use legacies has allowed fire-sensitive species to establish creating an opportunity for different mixedwood types to develop (e.g., pine-oak, pine-poplar, pine-gum). While any mixedwoods combination would increase tree species diversity relative to a monoculture, interest exists in whether silvicultural intervention can improve the performance of individual species to promote the development of different mixture types based on specific management objectives (e.g., wildlife habitat, timber quality, drought resistance). To address this question, we established an experiment examining the response of juvenile volunteer loblolly pine and six planted hardwood species (northern red oak, white oak, sweetgum, blackgum, yellow-poplar, and mockernut hickory to four silvicultural treatments (controlled release hardwood fertilization, coppicing, coppicing + broadcast fertilization, and planted control) in northern Mississippi, USA.Four-years post-planting, our results demonstrate that all treatments produced loblolly pine-hardwood co-dominance; however, hardwood dominance varied among treatments. In the planted control, loblolly pine and sweetgum were the co-dominant species, and statistically outgrew all species except yellow-poplar. Mockernut hickory (+ 40%), yellow-poplar (+ 23%), and blackgum (+ 15%) seedling height increased in controlled release fertilization compared to the planted control; however, apart from northern red oak, seedling survival of all hardwood species was less than 50%. The controlled release hardwood fertilization treatment was co-dominated by loblolly pine, yellow-poplar, and sweetgum. Sprouting in the coppiced treatment (89%) statistically exceeded that in the coppiced + broadcast fertilization treatment (73%), but did not vary among species. In general, coppicing reduced sprout height and survival relative to seedlings in the planted control, and promoted loblolly pine, yellow poplar, and sweetgum co-dominance. Coppicing + broadcast fertilization consistently reduced sprout survival compared to the planted control. However, trends in seedling height were mixed, with northern red oak (+ 14%) showing the largest improvement, and volunteer loblolly pine the largest decline (- 34%). Moreover, coppicing + broadcast fertilization produced the most species diverse outcome featuring yellow-poplar, loblolly pine, sweetgum, and northern red oak in co-dominant growing positions. Collectively, these results indicate that sweetgum and loblolly pine are likely to be prominent species in contemporary mixedwoods regardless of treatment. However, more species-diverse mixtures may be promoted by coppicing and broadcast fertilizing early in stand development.