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During a limited period in the summer of 2021, 17-year cicada species (Magicicada cassini , M. septendecula , M. septendecim) represented a large pulse of easily accessible food unique to forest ecosystems in the eastern United States. Using trail cameras and acoustic recorders, we tested whether the activity levels of 8 mammal species in northwestern Indiana shifted in response to spatial and temporal variation in cicada densities from 18 May to 20 June 2021. Cicada densities varied temporally and spatially across all study sites. Most mammal species with sufficient data showed no response to cicada emergence, including 2 tree squirrel species, Peromyscus mice, Eastern Chipmunks (Tamias striatus), and 2 species of bats. Raccoons (Procyon lotor), likely cicada predators, showed a quadratic or more complex activity response to cicada abundance, indicating a potential saturation point at densities near 1 cicada per m2. Surprisingly, White-tailed Deer (Odocoileus virginianus) activity decreased to almost 0 at the same cicada densities when we expected no change in activity. While size or accessibility may exclude cicadas as prey for small and volant mammals, our results suggest predation and satiation by Raccoons. In contrast, deer may be avoiding areas of cicada abundance due to other stimuli, such as high noise output, which may decrease their ability to detect predators. [ABSTRACT FROM AUTHOR]

This study challenges a long-standing and often uncontested assertion in the forestry discourse that maximizing financial returns always requires ecologically simplified stands. We developed a high-resolution simulation tool for northern hardwood stands in eastern North America and integrated advanced numerical optimization methods to model the tree-level harvest decisions that maximize financial returns. We modeled each individual tree's growth and its probability of natural mortality, conditioned on the evolving neighborhood-scale competitive environment it resides in. We developed size-, species-, and grade-specific price functions to assign potential harvest revenue values to each discrete bole section of each standing tree, and we used an evolutionary search algorithm to specify the financially optimal timing of tree-by-tree removals. We modeled three different case studies, representing a broad range of northern hardwood stand conditions, including a hypothetical 50-year-old, even-aged stand and two inventoried stands in northern New York, USA, with contrasting management histories. We observed consistent results across all three cases: maximizing financial returns from northern hardwood forests requires silvicultural finesse and results in ecologically complicated stands. [ABSTRACT FROM AUTHOR]

Soil respiration is the largest single efflux in the global carbon cycle and varies in complex ways with climate, vegetation, and soils. The suppressive effect of nitrogen (N) addition on soil respiration is well documented, but the extent to which it may be moderated by stand age or the availability of soil phosphorus (P) is not well understood. We quantified the response of soil respiration to manipulation of soil N and P availability in a full-factorial N x P fertilization experiment spanning 10 years in 13 northern hardwood forests in the White Mountains of New Hampshire, USA. We analyzed data for 2011 alone, to account for potential treatment effects unique to the first year of fertilization, and for three 3-year periods; data from each 3-year period was divided into spring, summer, and fall. Nitrogen addition consistently suppressed soil respiration by up to 14% relative to controls (p ≤ 0.01 for the main effect of N in 5 of 10 analysis periods). This response was tempered when P was also added, reducing the suppressive effect of N addition from 24 to 1% in one of the ten analysis periods (summer 2012–2014, p = 0.01 for the interaction of N and P). This interaction effect is consistent with observations of reduced foliar N and available soil N following P addition. Mid-successional stands (26–41 years old at the time of the first nutrient addition) consistently had the lowest rates of soil respiration across stand age classes (1.4–6.6 µmol CO2 m−2 s−1), and young stands had the highest (2.5–8.5 µmol CO2 m−2 s−1). In addition to these important effects of treatment and stand age, we observed an unexpected increase in soil respiration, which doubled in 10 years and was not explained by soil temperature patterns, nutrient additions, or increased in fine-root biomass. [ABSTRACT FROM AUTHOR]

The construction and operation of waterworks has a significant impact on natural ecosystems. The evaluation of their negative impact and the proposal to minimize their impact, as well as the revitalization, especially of large rivers, have been given great importance in recent decades. The main goal of the study is to present impact of Gabčíkovo Waterwork on forest ecosystems after 30 years of damming. Specially evaluated are monitoring sites where changes are observed in the Slovak part of the so-called inland delta, i.e., between old and new riverbed of the Danube. The assessment of changes in terrestrial vegetation on selected monitoring sites was compared with the assessment of parallel measured soil moisture data. At the same time, data from the National Forestry Centre were also used to monitor changes in the state of forest ecosystems in the whole area of interest. When comparing the species composition from state to 2015 and from the period before GW was put into operation (in 1990) an increase was found in the area share of hardwood floodplain forest by 5.77% and the area shares of softwood floodplain forests decreased by 1.71%. Between 1990 and 2015, 68.43% of the territory remained unchanged at the level of forest type groups. A change in habitat conditions towards drier forest types was recorded on 23.61% of the territory. [ABSTRACT FROM AUTHOR]

Aim: Spatiotemporal variation in resource availability is a strong driver of animal distributions. In the northern hardwood and boreal forests of the northeastern United States, tree mast events provide resource pulses that drive the population dynamics of small mammals, including the American red squirrel (Tamiasciurus hudsonicus), a primary songbird nest predator. This study sought to determine whether mast availability ameliorates their abiotic limits, enabling red squirrel elevational distributions to temporarily expand and negatively impact high‐elevation songbirds. Location: Northeastern United States. Methods: We used two independent datasets to evaluate our hypotheses. First, we fit a dynamic occupancy model using data from camera trap surveys to evaluate red squirrel distributional responses to pulses in the tree mast. We also assessed population responses using systematic auditory surveys analysed with an open‐population binomial mixture model. Further, we used modelled red squirrel abundance in nest‐survival models to evaluate whether their abundance is correlated with the daily nest survival of three songbird species. Results: The tree mast provided a critical resource pulse that resulted in a two‐fold increase in the annual elevational distribution of red squirrels. The elevational distribution of red squirrels ranged from a minimum of ~450 m (range: 663–1145 m asl) following two consecutive years without a masting event to a maximum of over 1000 m (range: 443–1545 m asl) after a large mast event. The daily nest survival of three songbird species tended to decline with an increase in the abundance of red squirrels. Main Conclusions: Tree mast is a central biological phenomenon in many temperate and boreal forests. This study reveals how this resource pulse results in range changes in a small mammal that is both a seed and bird predator, as well as prey for many carnivores. Thus, understanding this phenomenon can inform the conservation and management of northern forests, including breeding songbirds. [ABSTRACT FROM AUTHOR]

Measurements of net primary productivity (NPP) and litter decomposition from tropical peatlands are severely lacking, limiting our ability to parameterise and validate models of tropical peatland development and thereby make robust predictions of how these systems will respond to future environmental and climatic change. Here, we present total NPP (i.e., above‐ and below‐ground) and decomposition data from two floristically and structurally distinct forested peatland sites within the Pastaza Marañón Foreland Basin, northern Peru, the largest tropical peatland area in Amazonia: (1) a palm (largely Mauritia flexuosa) dominated swamp forest and (2) a hardwood dominated swamp forest (known as 'pole forest', due to the abundance of thin‐stemmed trees). Total NPP in the palm forest and hardwood‐dominated forest (9.83 ± 1.43 and 7.34 ± 0.84 Mg C ha−1 year−1, respectively) was low compared with values reported for terra firme forest in the region (14.21–15.01 Mg C ha−1 year−1) and for tropical peatlands elsewhere (11.06 and 13.20 Mg C ha−1 year−1). Despite the similar total NPP of the two forest types, there were considerable differences in the distribution of NPP. Fine root NPP was seven times higher in the palm forest (4.56 ± 1.05 Mg C ha−1 year−1) than in the hardwood forest (0.61 ± 0.22 Mg C ha−1 year−1). Above‐ground palm NPP, a frequently overlooked component, made large contributions to total NPP in the palm‐dominated forest, accounting for 41% (14% in the hardwood‐dominated forest). Conversely, Mauritia flexuosa litter decomposition rates were the same in both plots: highest for leaf material, followed by root and then stem material (21%, 77% and 86% of mass remaining after 1 year respectively for both plots). Our results suggest potential differences in these two peatland types' responses to climate and other environmental changes and will assist in future modelling studies of these systems. [ABSTRACT FROM AUTHOR]

Global change has created less stable forest systems and given urgency to understanding limitations to the establishment of tree seedlings beyond current range boundaries. We quantified trends in 13 years of annual northern red oak (QURU) seedling survival data for 1733 marked individuals at a local species distribution boundary within the northern hardwood forest in New Hampshire, USA. Over the study period, the median distance of seedlings into the valley did not change, although there was a net gain of 89 plots (5 m2) occupied. For a subset of seedlings that were marked in their year of birth (N = 937), we examined relationships among terrain, vegetation community, and initial individual seedling traits, and evaluated their effects on time to seedling mortality using a parametric accelerated failure time model. The year of seedling germination had the largest effect on survival with increasing mortality rates for seedlings from more recent cohorts. Seedlings had longer survival times where oak seedling densities were lower, shrub cover was higher, and when the acorn remained attached. Additionally, survival time was increased in higher elevation plots, which were also located further into the valley. Interannual seedling survival (N = 1580) was strongly impacted by seedling condition in the previous year, particularly leaf number and amount of leaf damage. Most seedling deaths occurred over winter, and seedlings failed to break bud the following spring. Interannual variation in seasonal climate, particularly deep, heavy snowpack in 2019 followed by drought conditions in 2020, coincided with recent elevated mortality. Overall, the median survival time of 3–4 years and the rapid turnover of the oak seedling population currently limit ability for expansion, although the net gain of occupied plots and increase in survival at higher elevation plots with lower QURU densities present some mechanisms that could promote expansion if the current suboptimal understory conditions shift to favor QURU. [ABSTRACT FROM AUTHOR]

Vegetation communities in restored bottomland hardwood forests in northeast Indiana were studied 6–21 years after restoration to assess progress toward restoration objectives. The study focused on four sites that were restored to compensate for resource injuries after contaminant releases. The restored sites were compared with four reference‐site conditions, including crops (prerestoration condition), old field communities representing a no‐management alternative, locally sampled second‐growth mature forests, and forest community types described by the US National Vegetation Classification (USNVC), which represent ideal or defining conditions of recognized vegetation communities. Fixed‐area plots provided data on field‐sampled environmental variables, vegetation, soil, and hydrological conditions for crops, old fields, restored areas, and mature forests. The USNVC database provided quantitative data for three historically and geographically relevant reference forest community types for comparison with the sampled communities. Results of nonmetric multidimensional scaling based on species cover revealed clear gradients relating to site age and canopy development. Along those gradients, restored areas demonstrated increasing similarity to mature forest reference communities in terms of floristic composition. Specifically, the floristic quality of restored areas was significantly greater than that of crops and old fields. Furthermore, soil health measurements of physical, chemical, and hydrological conditions indicated significant improvements in restored site soils compared with prerestoration conditions represented by cropland soils. Descriptions and data from the USNVC provided ecological context for restoration target conditions and facilitated the assessment of restoration recovery along a trajectory from starting conditions to those target conditions. Descriptions by USNVC also helped identify deviations from the intended restoration objectives (e.g., invasive species recruitment) and potential adaptive management actions to return sites to their intended trajectories. Integr Environ Assess Manag 2024;20:1917–1938. Published 2024. This article is a U.S. Government work and is in the public domain in the USA. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Key Points: Bottomland forest restoration sites were sampled to document the recovery of vegetation communities, soil and hydrological conditions, carbon storage, the return of lost services, and the functional status of the forest ecosystem.Restored sites were compared with a range of reference communities representing starting conditions (cropland), no‐management old fields, local mature second‐growth forests, and historically and geographically relevant US National Vegetation Classification communities.Vegetation community composition placed the four sampled restoration sites on an age‐related gradient between crops and mature forests, driven by indicators of canopy development and shifts in ground flora to species that thrive in shaded conditions.Improved ecological function in restored site soils was reflected in lower bulk density, increased water aggregate stability, and greater infiltration capacity, indicators of increased nutrient processing and reduced runoff, which are known to reduce sediment and nutrient loads in receiving streams. [ABSTRACT FROM AUTHOR]

Amphibians such as frogs, toads, and salamanders provide important services in aquatic and terrestrial ecosystems and have been proposed as useful indicators of progress and success for ecological restoration projects. Limited guidance is available, however, on the costs and benefits of different amphibian monitoring techniques that might be applied to sites restored in compensation for contaminant injury. We used a variety of methods to document the amphibian communities present at 4 restored bottomland hardwood sites in Indiana, USA, and to compare the information return and cost of each method. For 1 method—automated recording units—we also modeled the effect of varying levels of sampling effort on the number of species detected, using sample‐based rarefaction and Bayesian nonlinear (Michaelis–Menten) mixed effects models. We detected 13 amphibian species across the restored sites, including 2 species of conservation concern in Indiana—northern leopard frogs (Lithobates pipiens) and Blanchard's cricket frogs (Acris blanchardi). Sites across a range of restoration ages demonstrated encouraging returns of amphibian communities. Although more mature sites showed greater species richness, recently restored sites still provided important habitat for amphibians, including species of conservation concern. Among the 4 methods compared, amphibian rapid assessment yielded the highest number of species detected and the greatest catch per unit effort, with the lowest per‐site cost. Our analysis of level‐of‐effort effects in the rarefied acoustic data found that number of nights sampled was a better predictor of observed species richness than the number of hours sampled within a night or minutes sampled within an hour. These data will assist restoration practitioners in selecting amphibian monitoring methods appropriate for their site characteristics and budget. Integr Environ Assess Manag 2024;20:1939–1953. Published 2019. This article is a U.S. Government work and is in the public domain in the USA. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC) Key Points: Incorporating amphibians into restoration monitoring can improve accounting of ecosystem service returns on sites restored in compensation for contaminant injury. Amphibian rapid assessments detected the greatest number of species at the lowest per‐site cost. Sample‐based rarefaction of acoustic data from automated recording units indicated that increasing the number of nights sampled was the most efficient way to increase observed species richness. [ABSTRACT FROM AUTHOR]

Resolving a robust phylogeny of an organismal group is often hindered by the limited availability of samples suitable for genomic or transcriptomic sequencing. Even for lineages of notable importance in evolutionary ecology, our phylogenetic comprehension remains largely unsatisfactory due to the challenges of acquiring samples across the clade. The long‐horned beetle genus Anoplophora Hope exemplifies such a group, globally renowned for two invasive pests—the Asian long‐horned beetle and citrus long‐horned beetle—which have inflicted significant damage to deciduous hardwood forest in North America and Europe. In contrast to the two temperate pests, the remaining 50 species in the genus inhabit subtropical forests of Southeast Asia, where most species are only infrequently encountered. Here, we present the first comprehensive phylogeny of Anoplophora using a PCR‐based target enrichment museomics approach. As a case study of employing PCR‐generated custom probes, we demonstrate the robustness and cost‐effectiveness of this in‐house method in successfully acquiring sequence data from historical specimens. Through extensive sampling of Anoplophora using museum specimens, we reveal a non‐sister relationship between the two temperate species and provide evidence for addressing taxonomic conundrums. Our biogeographical analyses indicate that the adaptation of the two temperate species occurred independently during the late Pliocene and Pleistocene after the establishment of temperate forests in East Asia in the late Miocene. Our findings highlight the importance of comprehensive phylogenetic inference in understanding the patterns and processes of these beetles' adaptation to temperate forests and lay the groundwork for investigating the genetic mechanism underlying life in the cold. [ABSTRACT FROM AUTHOR]

This study explores how data from a handheld mobile laser scanning (MLS) system and quantitative structural models (QSM) can be used to estimate tree structural attributes. Four MLS acquisition scenarios were investigated in a 1 ha temperate hardwood stand, including 15 and 35 m parallel lines, nine circular plots, and a 20 m × 20 m grid. Results were compared against terrestrial laser scanning and destructive field measurements. All acquisition scenarios yielded comparable results, except for the 35 m scenario, which showed greater variability. The 20 m × 20 m grid scenario showed the highest accuracy, with an RMSE of 0.41 m (2.07%) for tree height, 3.98 cm (14.93%) for diameter at breast height, 0.21 m³ (19.28%) for merchantable wood volume, and 0.07 m³ (10.11%) for merchantable stem volume. A bias < 5% was observed for these key attributes, except for an 11.68% bias in merchantable wood volume. Overestimation of branch volume was identified as the primary source of bias related to merchantable wood volume. This study highlights MLS's potential for accurate, non-destructive estimation of tree structural attributes, while pointing out the need to refine noise removal and to assess the most suitable acquisition scenarios for various forest types. [ABSTRACT FROM AUTHOR]

Bottomland hardwood (BLH) forest ecosystems within the Lower Mississippi Alluvial Valley exist in narrow corridors composed of frequently flooded mature forests and complemented by afforested younger forest patches due to BLH afforestation efforts. Sylvilagus aquaticus (Swamp Rabbit), a BLH forest-specialist species, require a diversity of habitat conditions, but little information exists on fine-scale Swamp Rabbit use of mature and young forest habitats and the conditions that may influence Swamp Rabbit habitat use. We addressed this literature gap by assessing use of habitat by Swamp Rabbits in afforested and mature BLH stands in southern Illinois during March 2014–March 2016. At 746 plots (area = 3.15 m2, 60 m x 60 m spacing), we used Swamp Rabbit fecal pellets to quantify Swamp Rabbit habitat use and identified 9 habitat variables known to be important to Swamp Rabbits. We then created 18 a priori generalized linear models to evaluate variation in Swamp Rabbit habitat use relative to habitat variables each study year. Individual forest stands strongly influenced Swamp Rabbit habitat use in all 3 study years in addition to macro-habitat variables (i.e., distance to water, distance to afforested–mature stand interface) and micro-habitat variables (i.e., woody stem density, herbaceous ground cover) in some years. We found that both mature and afforested stands were used by Swamp Rabbits but that edaphic conditions specific to stands likely affected flooding and water inundation in localized areas impacting habitat conditions and thus Swamp Rabbit use. While we found increased ground vegetation and woody stem density had positive impacts on habitat use by Swamp Rabbits in 2014, these variables were no longer significant predictors of Swamp Rabbit occupancy when flooding was severe in 2015 and the following year, 2016. These results point towards water inundation from flooding as the main driver of Swamp Rabbit habitat use when it limits terrestrial habitat and the availability of vegetation resources important for food and hiding cover. Because Swamp Rabbit habitat use is driven by habitat at the stand scale, habitat management can focus on managing stands with more consistently dry conditions to provide all necessary habitat elements when lower elevations are unavailable due to inundation. This research underscores the annual variability of these forest ecosystems and the importance of incorporating forest vegetation dynamics, hydrogeomorphology and flooding incidence and severity into management plans for Swamp Rabbits. [ABSTRACT FROM AUTHOR]

Animals benefit from scatterhoarding, storing food around their home range for use during a period of scarcity, by later eating the stored food. Seedlings may be used as cues of belowground food. We investigated whether scatterhoarders such as eastern gray squirrels (Sciurus carolinensis Gmelin, 1788) and eastern chipmunks (Tamias striatus (Linnaeus, 1758)) use characteristics of seedlings and their seeds as physical cues of the value of the seed. We buried 176 germinating seeds (white oak (Quercus alba L.) and northern red oak (Quercus rubra L.)) in a hardwood forest in Alabama, USA. Seeds were recovered faster with longer leaves (rate ratio (RR) = 0.68, 0.58–0.78, 95% confidence limits (C.L.)) and taller stems (RR = 0.91, 0.88–0.93, 95% C.L.) during spring 2022, and with a smaller number (RR = 1.15, 1.04–1.27, 95% C.L.) of longer leaves (RR = 0.81, 0.70–0.93, 95% C.L.) during fall 2022 (both P < 0.0001). For all seeds, we found that longer roots increased the likelihood of seeds being used (rather than ignored; odds ratio = 1.45, 1.00–2.09, 95% C.L., P = 0.05). We found new evidence suggesting that hoarders use aboveground cues from the seedling to dig it up and belowground seedling cues to assess seed value. These findings add to our understanding of assessing food availability for hoarding animals. [ABSTRACT FROM AUTHOR]

Automated radio telemetry systems have become a popular and invaluable tool in tracking the activity and movement of wild animals. However, many environmental conditions can hinder accuracy when tracking with this technology. For instance, study sites may contain multiple habitat types, each habitat uniquely affecting the signal strength received from tagged species. To investigate the influence of a structurally diverse study site on an automated radio telemetry system, we conducted this project at a restored and managed pine barren habitat that consisted of a mix of mature pitch pine, treated pitch pine, scrub oak, and hardwood forests. This site, Montague Plains Wildlife Management Area, Montague, Massachusetts, is also a known breeding ground for Eastern whip-poor-will (Antrostomus vociferus). To measure the relationship of radio signal strength with distance across each habitat, we used radio telemetry equipment manufactured by Cellular Tracking Technologies. We produced negative exponential decay functions measuring radio signal strength over distance and tested for differences among habitat types on radio signal strength (RSS). We found that decay function parameters significantly differed by habitat type, prompting us to investigate if accounting for these differences improved location estimate accuracy. To test this, we estimated known locations using trilateration methods with and without habitat calibration. Comparing these tests indicates that habitat-specific adjustments significantly improved location accuracy. Lastly, we visualized estimated RSS-based locations of 1 week of whip-poor-will data and compared them to GPS data generated from the same individual. Previous studies have accounted for types of environmental interference (like elevation) in the field but have avoided incorporating habitat-specific factors by working with node networks covering a relatively small area, but in this study, we examined the potential to scale up for larger areas and in more complex habitats. [ABSTRACT FROM AUTHOR]

Rising temperatures, increasing hydroclimate variability and intensifying disturbance regimes increase the risk of rapid ecosystem conversions. We can leverage multi‐proxy records of past ecosystem transformations to understand their causes and ecosystem vulnerability to rapid change.Prior to Euro‐American settlement, northern Indiana was a mosaic of prairie, oak‐dominated forests/woodlands and beech‐dominated hardwood forests. This heterogeneity, combined with well‐documented but poorly understood past beech population declines, make this region ideal for studying the drivers of ecosystem transformations.Here, we present a new record from Story Lake, IN, with proxies for vegetation composition (pollen), fire (charcoal) and beech intrinsic water use efficiency (δ13C of beech pollen; δ13Cbeech). Multiple proxies from the same core enable clear establishment of lead–lag relationships. Additionally, δ13Cbeech enables direct comparisons between beech population abundance and physiological responses to changing environments. We compare Story Lake to a nearby lake‐level reconstruction and to pollen records from nearby Pretty and Appleman Lakes and the distal Spicer Lake, to test hypotheses about synchrony and the spatial scale of governing processes.The 11.7 ka sediment record from Story Lake indicates multiple conversions between beech‐hardwood forest and oak forest/woodland. Beech pollen abundances rapidly increased between 7.5 and 7.1 ka, while oak declined. Oak abundances increased after 4.6 ka and remained high until 2.8 ka, indicating replacement of mesic forests by oak forest/woodland. At 2.8 ka, beech abundances rapidly increased, indicating mesic forest reestablishment. Beech and oak abundances correlate with charcoal accumulation rates but beech abundance is not correlated with δ13Cbeech.Fluctuations in beech abundances are synchronous among Story, Appleman and Pretty Lakes, but asynchronous between Story and Spicer Lakes, suggesting regulation by local‐scale vegetation‐fire‐climate feedbacks and secondarily by regional‐scale drivers.Holocene forest composition and fire dynamics appear to be closely co‐regulated and may be affected by local to regional climate variations. The importance of extrinsic drivers and positive/negative feedbacks changes over time, with higher ecoclimate sensitivity before 2.8 ka and greater resilience afterwards.Synthesis: Overall, oak‐ and beech‐dominated ecosystems were highly dynamic over the Holocene, with multiple ecosystem conversions driven by shifting interactions among vegetation, hydroclimate and fire regime. [ABSTRACT FROM AUTHOR]

Forests in northeastern North America have undergone dramatic transformations due to losses and gains of species, changes in land use and pollution. Historic stressors combined with new threats of white‐tailed deer and non‐native earthworms are threatening native plant diversity.We developed a transplant approach to gauge the importance of deer and earthworms in allowing understorey species recovery. This approach, instead of censusing existing individuals, avoids problems imposed by past land use, dispersal limitation or climate change. We selected 20 native species in different taxonomic and functional groups, with different palatability to herbivores, different life‐history strategies and a range of plant traits (%N, specific leaf area [SLA]) and our selection included species indicative of primary or secondary forests.Using a 2 × 2 full factorial design, we planted species into fenced and unfenced plots with and without existing earthworm invasions in five secondary hardwood forests. We measured survival, plant growth and reproduction over 4–6 years.Earthworm biomass was associated with increased survival of 13 and decreased survival of five species. Surviving transplants grew taller (eight of 12 species measured) and wider (seven of nine species measured) in earthworm plots but were more likely to be attacked by insects. Excluding deer benefitted most species' survival and growth.Taxonomic class, SLA or foliar N did not affect species sensitivity to deer or earthworms.Synthesis. Secondary forests in our region continue to provide suitable habitat for native species. Earthworms and deer are major structuring forces affecting survival and growth of our transplant species, but their impacts are species‐specific and change over time. We observed poorly recognized indirect negative impacts of deer on many unpalatable species. Taxonomic class and differences in plant traits offered no important insights regarding vulnerability to deer or earthworms. Transplanting native species into secondary forests can succeed in restoring understorey communities, but will require fencing or substantial deer population reductions to be successful long term. [ABSTRACT FROM AUTHOR]

Evapotranspiration (ET) is a major component of the water budget in Bottomland Hardwood Forests (BHFs) and is driven by a complex intertwined suite of meteorological variables. The understanding of these interdependencies leading to seasonal variations in ET is crucial in better informing water resource management in the region. We used structural equation modeling and AIC modeling to analyze drivers of ET using Eddy covariance water flux data collected from a BHF located in the Russel Sage Wildlife Management Area (RSWMA). It consists of mature closed-canopy deciduous hardwood trees with an average canopy height of 27 m. A factor analysis was used to characterize the shared variance among drivers, and a path analysis was used to quantify the independent contributions of individual drivers. In our results, ET and net radiation (Rn) showed similar variability patterns with Vapor Pressure Deficit (VPD) and temperature in the spring, summer, and autumn seasons, while they differed in the winter season. The path analysis showed that Rn has the strongest influence on ET variations via direct and indirect pathways. In deciduous forests like BHFs, our results suggest that ET is more energy dependent during the growing season (spring and summer) and early non-growing season (autumn) and more temperature dependent during the winter season. [ABSTRACT FROM AUTHOR]

An array of lake sediment proxies including paleobotanic, geochemical, and historical records has been used to determine former environments of Bugbee Pond, a small, mesotrophic pond in northeastern Minnesota. Much research has been produced on the history of climate and vegetation change of the region, yet we have little information on the impact of human settlement. This well-dated, high resolution, multi-proxy record is important for its length and concentration on the historic period. The lake itself became established by ~7000 years ago. Pollen evidence suggests a transition between the regional Prairie Period to the Great Lakes mixed conifer – hardwood forest was established in the region at this time. XRF data suggest dry basin accumulation early in the record after ~7000 cal yr BP, but lake levels substantially increased by ~5600 cal yr BP, during a regionwide climatic transition to more humid conditions. Birch and boreal conifers increased after about 3800 cal yr BP; further increases in boreal conifers occurred by ~2000 cal yr BP. Anthropogenic vegetation changes during the Historic period, beginning in the late 19th century, is well represented by forest clearance of white pine (Pinus strobus), followed by increases in early successional species and an increased sediment accumulation rate due to land clearance. Establishment of farming communities locally are shown by occurrence of corn (Zea mays) and oat (Avena sativa) pollen, and pasturing and grazing are documented by Rumex, Fabaceae and Poaceae pollen, as well as coprophilous fungi, such as Sordaria. The increase and subsequent decline in Pb and S concentrations in the uppermost sediments are mirrored by historically documented, nearby industrial activities. [ABSTRACT FROM AUTHOR]

The scarab genus Osmoderma (Coleoptera: Scarabaeidae) includes several large species called hermit beetles that develop within dead and decaying hardwood trees. Males of at least three Palearctic species produce the aggregation-sex pheromone (R)-(+)-γ-decalactone, including the endangered O. eremita (Scopoli). However, hermit beetles have received less attention in the western hemisphere, resulting in a large gap in our knowledge of the chemical ecology of Nearctic species. Here, we identify (R)-(+)-γ-decalactone as the primary component of the aggregation-sex pheromone of the North American species Osmoderma eremicola (Knoch). Field trials at sites in Wisconsin and Illinois revealed that both sexes were attracted to lures containing (R)-(+)-γ-decalactone or the racemate, but only males of O. eremicola produced the pheromone in laboratory bioassays, alongside an occasional trace of the chain-length analog γ-dodecalactone. Females of the congener O. scabra (Palisot de Beauvois) were also significantly attracted by γ-decalactone, suggesting further conservation of the pheromone, as were females of the click beetle Elater abruptus Say (Coleoptera: Elateridae), suggesting that this compound may have widespread kairomonal activity. Further research is needed to explore the behavioral roles of both lactones in mediating behavioral and ecological interactions among these beetle species. [ABSTRACT FROM AUTHOR]

Successional, second-growth forests dominate much of eastern North America; thus, patterns of biomass accumulation in standing trees and downed wood are of great interest for forest management and carbon accounting. The timing and magnitude of biomass accumulation in later stages of forest development are not fully understood. We applied a "chronosequence with resampling" approach to characterize live and dead biomass accumulation in 16 northern hardwood stands in the White Mountains of New Hampshire. Live aboveground biomass increased rapidly and leveled off at about 350 Mg/ha by 145 years. Downed wood biomass fluctuated between 10 and 35 Mg/ha depending on disturbances. The species composition of downed wood varied predictably with overstory succession, and total mass of downed wood increased with stand age and the concomitant production of larger material. Fine woody debris peaked at 30–50 years during the self-thinning of early successional species, notably pin cherry. Our data support a model of northern hardwood forest development wherein live tree biomass accumulates asymptotically and begins to level off at ∼140–150 years. Still, 145-year-old second-growth stands differed from old-growth forests in their live (p = 0.09) and downed tree diameter distributions (p = 0.06). These patterns of forest biomass accumulation would be difficult to detect without a time series of repeated measurements of stands of different ages. [ABSTRACT FROM AUTHOR]

Carbon sequestration in the forests of the eastern United States is an important offset to the country's CO2 emissions. Much of the eastern forestland is the product of reforestation of abandoned agricultural land or recovery following clear‐cutting over a century ago. This has led to concerns that eastern forests are even‐aged and that rates of carbon sequestration will decline as forests increase in carbon. Our objective was to examine the successional dynamics of forest carbon sequestration—using live tree carbon stocks as a proxy for successional status—for the six broadly defined forest types present in the region. We used datasets from the National Forest Inventory (NFI) for the 31 US states from Minnesota south to Louisiana and eastward and analyzed live tree net carbon increment for 2007–2021, the period for which NFI plot remeasurement data were available for all 31 states. Spruce–fir and southern pines were the only forest types for which carbon increment declined even modestly over a significant fraction of the range of live tree carbon observed in the region, and southern pine–hardwood forests were the only forests in which predicted sequestration in live tree carbon declined to zero within the range of carbon stocks observed in the region. Northern hardwood–conifer forests, oak–hickory forests, and lowland forests experienced either no decline or a slight increase in sequestration in live tree carbon across the range of successional status observed in the region. Thus, the average stocks of live tree carbon per unit area increased steadily over the study period. At some point in succession, rates of mortality are expected to increase and balance gross growth, leading to zero net sequestration in live tree carbon. Mature and old‐growth stands, however, are rare in all six forest types, and mortality as a fraction of live tree carbon for all six forest types declined across the range of successional status present in the region. Our results thus provide no support for the hypothesis that the successional dynamics of forests in this region can be expected to lead to near‐term declines in net carbon sequestration. [ABSTRACT FROM AUTHOR]

In northern hardwood forests, tree markers select the trees to be harvested during logging operations using classification systems that assign harvest priorities based on the presence of a wide range of individual defects. According to the most recent advances in our understanding of the impact of defects on both tree vigour (the risk of mortality or decline in growth) and quality (the potential for recovering valuable sawlogs), tree markers should adopt a simpler classification system that considers fewer defects than the current operational practice, and they should prioritize the removal of trees with crown dieback. Since the probability of developing defects and dying increases substantially with tree diameter, tree markers should also favour the removal of larger trees that have maintained their quality. However, these recommendations were developed based on tree-level analyses. To provide further validation at the stand scale, we compared stand improvement and value recovery under three tree marking regimes: a new, simplified regime based on the recommendations above, and two regimes used in the province of Quebec, Canada. To do so, we conducted tree marking simulations and value recovery assessments in 14 managed stands distributed across the northern hardwood range of Quebec. Our results confirmed that the simplified tree marking regime not only facilitated stand improvement by removing a greater proportion of low-vigour trees, but also recovered significantly more value (17% on average) at the stand scale. By prioritizing the removal of trees with crown dieback, the simplified regime was superior at salvaging the current value of low-vigour trees before they die or decline in quality. Based on our results, we propose simplified and empirically-validated tree marking guidelines for northern hardwood forests. [ABSTRACT FROM AUTHOR]

Copyright of Fire Ecology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil organic matter (SOM) is a major global carbon (C) pool vulnerable to ongoing warming, as microbial SOM decomposition and CO2 respiration are sensitive to temperature. We characterized the edaphic characteristics that explain variation in soil C concentration, cycling, and temperature sensitivity (Q10) across two sites of differing elevation, forest community composition, and mineral parent material at Hopkins Memorial Forest, Williamstown, Massachusetts, USA. We found that the upper site maintained significantly higher surface soil C concentration, despite similar litterfall inputs across sites. We found large differences in the fraction of total soil C that is protected from microbial decomposition, with enhanced physical protection in macroaggregate-rich, upper site soils. Upper site plots maintain a higher relative abundance of plants producing lignin-rich litter, which may fuel aggregate formation and SOM protection. Experimental addition of glucose, vanillin, and lignin substrates produced broadly conserved respiratory responses across sites, suggesting that microbial communities maintain similar decomposition capacity, although lignin addition induced slightly elevated respiration responses in upper relative to lower site plots. Seasonal Q10 of soil respiration was higher at the upper site and increased with soil potassium (K+) availability across plots, potentially reflecting K+ constraints on autotrophic and heterotrophic metabolic activity. Our findings suggest that variation in the extent of physical protection of soil C, particularly through macroaggregate formation, is an important mechanism for long-term soil C storage at the site. Despite enhanced SOM physical protection at the upper site, the higher temperature sensitivity of soil respiration may reduce soil C in the context of future warming. [ABSTRACT FROM AUTHOR]

Copyright of Forestry Chronicle is the property of Canadian Institute of Forestry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forestry Chronicle is the property of Canadian Institute of Forestry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Mississippi Alluvial Valley (MAV) is an internationally important migration and wintering region for Nearctic waterfowl. Most of the MAV is a lowland forested floodplain that contains vast stands of red oaks (Quercus spp.). These trees produce acorns and, when forests flood, diverse communities of aquatic invertebrates emerge, providing diverse nutritious foods for wintering ducks. The MAV is within the Lower Mississippi Valley Joint Venture (LMV JV) region of the North American Waterfowl Management Plan, but no combined MAV‐wide estimates of acorn and invertebrate biomass exist to determine foraging carrying capacity for conservation planning or actions by the LMV JV or other partners in regions containing southern red oaks. We sampled acorns that fell to the ground or were submersed under shallow water deemed accessible to foraging ducks and aquatic invertebrates in the MAV of Louisiana, Mississippi, Missouri, and Tennessee, USA, during fall‐winter 2009–2011. In good and poor masting years, acorn abundance was non‐linearly related to the percentage of the forest canopy made up of red oaks and peaked in late autumn or winter when most other waterfowl resources are depleted or decomposed. This finding is novel and represents a deviation from how the LMV JV has traditionally assumed food resources exist for waterfowl in hardwood bottomlands. We used a daily ration model to estimate energy use days (EUDs) from combined acorn and invertebrate biomasses relative to red oak canopy coverage. For good and poor acorn masting years at the mean MAV‐wide red oak canopy coverage of 45%, EUD = 2,273.1 days/ha and 161.2 days/ha, respectively. The LMV JV currently uses EUD = 385–502 days/ha for forests with 40–50% red oak canopy coverage. Because acorns and aquatic macro‐invertebrates are a food resource that persists through winter and reaches peak abundance later in winter, we contend conservation planners have undervalued the potential of bottomland hardwoods to provide energy for wintering ducks. [ABSTRACT FROM AUTHOR]

Background: Central place foragers must acquire resources and return to a central location after foraging bouts. During the egg laying (hereafter laying) period, females are constrained to a nest location, thus they must familiarize themselves with resources available within their incubation ranges after nest site selection. Use of prospecting behaviors by individuals to obtain knowledge and identify profitable (e.g., resource rich) locations on the landscape can impact demographic outcomes. As such, prospecting has been used to evaluate nest site quality both before and during the reproductive period for a variety of species. Methods: Using GPS data collected from female eastern wild turkeys (Meleagris gallopavo silvestris) across the southeastern United States, we evaluated if prospecting behaviors were occurring during laying and what landcover factors influenced prospecting. Specifically, we quantified areas prospected during the laying period using a cluster analysis and the return frequency (e.g., recess movements) to clustered laying patches (150-m diameter buffer around a clustered laying period location) during the incubation period. Results: The average proportion of recess movements to prospected locations was 56.9%. Nest fate was positively influenced (μ of posterior distribution with 95% credible 0.19, 0.06–0.37, probability of direction = 99.8%) by the number of patches (90-m diameter buffer around a clustered laying period location) a female visited during incubation recesses. Females selected for areas closer to the nest site, secondary roads, hardwood forest, mixed pine-hardwood forest, water, and shrub/scrub, whereas they avoided pine forest and open-treeless areas. Conclusions: Our findings suggest that having a diverse suite of clustered laying patches to support incubation recesses is impactful to nest fate. As such, local conditions within prospected locations during incubation may be key to successful reproductive output by wild turkeys. We suggest that prospecting could be important to other phenological periods. Furthermore, future research should evaluate how prospecting for brood-rearing locations may occur before or during the incubation period. [ABSTRACT FROM AUTHOR]

Functional balance theory predicts that plants will allocate less carbon belowground when the availability of nutrients is elevated. We tested this prediction in two successional northern hardwood forest stands by quantifying fine root biomass and growth after 5–7 years of treatment in a nitrogen (N) x phosphorus (P) factorial addition experiment. We quantified root responses at two different levels of treatment: the whole-plot scale fertilization and small-patch scale fertilization of ingrowth cores. Fine root biomass was higher in plots receiving P, and fine root growth was highest in plots receiving both N and P. Thus, belowground productivity did not decrease in response to long-term addition of nutrients. We did not find conclusive evidence that elevated availability of one nutrient at the plot scale induced foraging for the other nutrient at the core scale, or that foraging for nutrients at the core scale responded to addition of limiting nutrients. Our observations suggest NP co-limitation of fine root growth and indicate complex interactions of N and P affecting aboveground and belowground production in early successional northern hardwood forest ecosystems. [ABSTRACT FROM AUTHOR]

White oak is a major commercial tree species and an important timber resource in Kentucky. However, current forest inventory trends from the Central Hardwood Forest Region (CHFR) reveal a sustainability threat from declining white oak regeneration and recruitment leading to a disproportionate inventory structure. Using Forest Inventory and Analysis (FIA) data together with the Forest Vegetation Simulator (FVS), we performed a base run analysis of projected inventory levels of white oak sawlogs to better understand whether the inventory level is sustainable to support the current harvest level of white oak in the future. The projections were further examined by tree grades to provide a general outlook on the quality of white oak timber growing in Kentucky's forests in posterity. By doing so, we generated results that indicate that projected inventory levels of white oak sawlogs cannot be considered sustainable to support current harvest levels from 2058 onwards. In addition, the long-term trends in inventory levels of high-quality white oak sawlogs would be continuously declining whereas that of low-quality sawlogs would be steadily increasing. On the brink of these significant inventory shifts, our study calls for proactive forest management approaches to stabilize the white oak timber resource supply in Kentucky and beyond. [ABSTRACT FROM AUTHOR]

We used trail cameras to monitor human visits and activities at two sites in northeast Indiana being restored to bottom-land hardwood forests. These sites, managed as nature preserves, are close to cities, where trails and parking lots have been added for ease of access. In this study, trail cameras were successfully used to capture visitation rates and activity types. The two sites had median visitor use rates of 1 and 13 visitors per day. Across both sites, "parking lot use only" (62%), hikers (30.2%), and bicyclists (5%) accounted for more than 97% of site visits. Overall, most weekday visitor-time occurred during daylight hours, peaking at lunch and evening. Mean total number of daily visitors was higher during weekends; however, total daily visitor-time did not vary between days of the week. Michaelis-Menten rarefaction models of sampling efficiency across the study's four camera stations suggest sampling duration of 27 to 55 days to accurately estimate mean daily visitor counts and 3 to 40 days to detect half the maximal numbers of observed activities. Study estimates of visitation provide land managers with information for accommodating visitor use activities on the restored sites and offer inputs for cultural ecosystem services assessments and associated economic analyses. [ABSTRACT FROM AUTHOR]

Saplings (tree species whose diameter at breast height ranges from 1.1 to 9.0 cm) are important in forest growth and development. Their abundance and density can lead to specific forest successional trajectories and ecosystem characteristics. Yet, the consideration of saplings in forest management planning is a relatively new topic and is still rarely included in forest growth models. We developed sapling density models for 10 species groups with the objective of providing forest managers with additional tools to support the development of more precise prediction systems. We used dendrometric and environmental variables to model sapling density and species-wise density ratios. We evaluated Poisson and gamma regressions for the modelling of sapling density and zero-inflated logistic regressions to model species ratios. We used repeated measurements (from 1982 to 2019) from permanent sample plots located in hardwood forests in northeastern North America. Our results show that the gamma regression was superior to the Poisson regression. The cross-validated mean bias using gamma regression was 55 stems·ha−1 with a relative percentage error of 2.5% and an R2 of 0.43. The species-wise sapling density ratio model had an overall R2 of 0.93, and the species-wise mean R2 ranged between 0.90 and 0.96. Among the examined model covariates, stem density of merchantable-sized trees and latitude were significant in both models. We believe that the models we developed can be useful for forest management planning and sustainable merchantable production. [ABSTRACT FROM AUTHOR]

The drivers of interannual variability (IAV) of net ecosystem exchange (NEE) in forested wetlands are poorly understood, making it difficult to predict changes in atmospheric fluxes in response to land use and climate change. Similarly, these ecosystems demonstrate dynamic physiological and phenological responses to climate over time yet are typically modeled using static parameters that represent unchanging ecological conditions. Though static first-order ecosystem models are informative, they fundamentally lack the ability to represent dynamic annual changes in ecological processes that may drive IAV of NEE through time. We aimed to improve understanding of how forested wetlands dynamically respond to climate and which key ecological processes may contribute to IAV of NEE. Simultaneously, we aimed to develop tools to evaluate dynamically parameterized process based first-order ecosystem models. To achieve these objectives, long-term ecological data were fused with the Total Ecosystem (TECO) model in three loblolly pine plantations and a bottomland hardwood forest of contrasting stand age in wetland areas of the lower coastal plain of North Carolina. Variance decomposition was used to assess changes in large-scale ecosystem drivers. To investigate individual processes, both static and dynamic data-assimilation were conducted to simulate time–invariant and time–varying ecological response. Anomalies in dynamic ecosystem process response were correlated with NEE anomalies to attribute IAV of NEE to underlying process-based mechanisms that may drive annual changes in NEE across stand age and sites. Assessment of large-scale drivers of IAV of NEE across sites demonstrated that maximum carbon uptake (MCU) dominated IAV of NEE in the mature pine plantation. These large-scale NEE signals were further parsed into ecological processes in the TECO model, where process anomaly correlation showed that slight variations in root maintenance respiration and woody biomass turnover rates may be underlying drivers of IAV of MCU and subsequently NEE. However, in the young pine plantations and bottomland hardwood forest IAV of NEE was not dominated by MCU. In contrast, IAV of NEE in young plantations was influenced most by annual changes in maximum carbon release (MCR) and carbon uptake period (CUP), while IAV of NEE in the bottomland hardwood forest was dominated by CUP. These results demonstrate that dynamic data assimilation (DA), variance decomposition, and process anomaly correlation are investigative and diagnostic tools for process-based models, though maximum GPP was systematically underestimated by models across sites. Despite problems with peak GPP representation, anomaly correlation between ecological processes and IAV of NEE allowed investigation of the specific ecological drivers of annual variability in ecosystem-level carbon exchange. As ecosystems show dynamic physiological and phenological properties through time, it may be important to allow models to have dynamic/time–varying ecological responses, especially if the root causes of IAV of NEE are to be attributed to ecological processes in process-based models. [ABSTRACT FROM AUTHOR]

Spring ephemerals are wildflowers found in temperate deciduous forests that typically display aboveground shoots for a period of 2 months or less. Early spring, before the canopy leaves out, marks the beginning of the aboveground growth period where ephemerals acquire nutrients and resources via aboveground tissues. Several studies have shown that spring ephemeral reproduction is affected by spring temperature, but few have looked at how weather conditions of the current and previous seasons, including precipitation and temperature, influence aboveground growth. Here, we examine the response of a spring ephemeral community in a temperate hardwood forest to weather conditions during their current and previous growing seasons. For 15 years we estimated percent cover of each species within our community. We highlighted five dominant spring ephemerals within this community: wild leek (Allium tricoccum), cutleaf toothwort (Cardamine concatenata), spring beauty (Claytonia virginica), squirrel corn (Dicentra canadensis) and trout lily (Erythronium americanum). We compared changes in cover on both a community and species level from 1 year to the next with average precipitation and temperature of the year of measurement as well as the year prior. We found precipitation and temperature influence a change in cover at the community and species level, but the strength of that influence varies by species. There were few significant correlations between plant cover in the current year and temperature and precipitation in the 30 days preceding measurement. However, we found significant correlations between plant cover and precipitation and temperature during the previous spring; precipitation and cover change were positively correlated, whereas temperature and cover change were negatively correlated. Overall, cooler, wetter springs lead to an increase in aboveground cover the next year. Learning how individual species within a forest plant community respond to weather conditions is a crucial part of understanding how plant communities will respond to climate change. [ABSTRACT FROM AUTHOR]

Raccoons (Procyon lotor) are the primary reservoir for rabies virus in eastern North America. Management of rabies in raccoons is achieved primarily with the use of oral rabies vaccination (ORV) and effective ORV bait densities are determined in part by the densities of raccoons. Decisions regarding ORV bait densities, however, are limited by an incomplete understanding of raccoon densities across the spectrum of landscapes they occupy. We carried out a mark‐recapture study of raccoons on the Savannah River Site in South Carolina, USA, from 2017–2019, to develop sex‐ and landscape‐specific raccoon density estimates across 4 rural land cover types in the southeastern United States: bottomland hardwood, riparian forest, isolated wetland, and upland pine (Pinus spp.). We captured 404 unique raccoons 773 times over the 3‐year trapping period. Estimated densities were 5.44 ± 0.37 (SE) animals/km2 in bottomland hardwood forest, 2.62 ± 0.32 animals/km2 in riparian forest, 2.19 ± 0.29 animals/km2 in isolated wetlands, and 2.14 ± 0.23 animals/km2 in upland pine. Densities were significantly higher in bottomland hardwood than all other land cover types, whereas densities among the remaining cover types were similar. These patterns are likely the result of landscape fragmentation and configuration, with riparian forests typically embedded in a matrix of less suitable cover types, leading to low densities despite presumably high resource availability. There were higher densities of males than females in every cover type except upland pine, where the sex ratio was balanced. Densities on our site were low compared to other rural areas, which likely results from the lack of human influence in terms of agriculture or development. The financial cost of baiting for ORV distribution may be reduced by considering the comparatively low densities of raccoons in these rural landscapes in the southeastern United States. [ABSTRACT FROM AUTHOR]

Silvicultural regeneration methods focus on manipulating the forest canopy, but success can depend on the use of site preparation to control competing vegetation, including the density of advance regeneration, and create suitable microsite conditions for germination and seedling establishment. Tip-up mounds are known to provide favorable conditions for some tree species, but the creation of tip-up mounds as a method of site preparation has scarcely been investigated. We assessed effects of artificial tip-up mounds on tree seedling composition across a gradient of regeneration methods and residual overstory densities 2–4 years post-implementation. We found that tree seedling communities on mounds in some treatments were compositionally distinct from untreated reference plots. However, no tree species exhibited a strong affinity for mounds when analyzed independently from the regeneration method, and much of the difference in composition was associated with lower dominance of maples (Acer spp. L.) on mounds. As maples are strong competitors in forests regenerated with selection systems, reduced maple competition on artificial mounds could advantage desired under-represented species and aid in natural regeneration over time. Therefore, in stands where promoting tree species diversity is desirable, implementing artificial tip-up mounds as part of a long-term strategy may be beneficial. [ABSTRACT FROM AUTHOR]

A mechanized1 harvesting system combined with whole-tree chipping was investigated on two harvesting sites in central and eastern Ohio, USA. Production and machine rate data of the operations were collected through time-motion studies, with chipping sub-tasks (elements) defined as: feeding, chipping, and loading. Chipping cycles averaged 21.5 min to produce 13.3 dry (21.3 green) tonnes per truckload, providing an hourly rate of 37.3 dry tonnes per productive machine hour (PMH), excluding delays. Total cycle time including truck delivery averaged 183 min, resulting in an hourly production rate of 4.4 dry tonnes/PMH delivered. The complete harvesting system included one feller-buncher, two grapple skidders, and a chipper. Harvesting cost ranged from (USD) $22.2 to $27.8/dry tonne, at the landing. Trucking cost was $0.48/dry tonne/km for the average hauling distance of 78 km. The total delivered cost amounted to $59.9–$65.5 per dry tonne. Chips were sampled from the operations and characterized to evaluate their quality as a bioenergy fuel, according to ANSI Standard AD17225–4:2014 Solid Biofuels. Results of chip properties indicated 37.5% green moisture (i.e. water mass fraction), 0.212 g/cm3 bulk density, 10.5% bark content, 0.49% ash, and 18.59 MJ/Kg calorific heating value. Size distribution of wood chips was categorized into small (3–<16 mm) 46%, medium (16–<45 mm) 45%, and large (45–63 mm) 3%, respectively. Fines (<3 mm) composed less than 1% while 4.5% were oversize (>63 mm). These whole-tree chips were found to meet the requirements of the highest grade (A1) of the U.S. wood chip fuel quality standard for bioenergy applications. [ABSTRACT FROM AUTHOR]

Abstract: Fog interception is a significant component of the water balance of Southern Appalachian spruce-fir forests in the Southeast USA. Here, fog interception rates are quantified for spruce-fir and northern hardwood trees in Great Smoky Mountains National Park (GSMNP), Tennessee and North Carolina, as a precursor to examining how interspecific differences in fog interception could affect catchment water balances if there is widespread vegetation change from spruce-fir to hardwoods. A water-balance approach was implemented, based on paired open-site (rainfall) and beneath-canopy (throughfall) electronically recording tipping-bucket rain gauges that were in place in the spruce-fir zone of GSMNP from May to November 2021. Comparing identified fog interception events to actual conditions captured by a webcam, 90% of verifiable events had conditions that were either clearly or potentially favorable for fog interception. Estimated fog interception gain ranged from averages of 0.24 to 0.69 mm day−1, representing 3 to 8% of rainfall. Results are consistent with the expectation of higher fog interception gain for spruce and fir than for birch, the representative hardwood species. Quantification of fog interception rates provides valuable information about ecohydrological processes in ecologically significant Southern Appalachian spruce-fir forests. [ABSTRACT FROM AUTHOR]

South Korean forests need hardwood tree species that can produce timber, as global warming progresses and the habitats of conifers dwindle. For the past 30 years, exotic yellow poplar (Liriodendron tulipifera) has been planted to replace some of the pine-dominated forests, as there is a lack of native hardwood tree species that produce large and good quality timber. However, yellow poplar growth has varied among planting sites across the country. We studied how environmental factors affect the growth of 49 stands of yellow poplar trees, with 945 dominant trees across 129 plots. To identify the optimal conditions for yellow poplar growth, we assessed 28 environmental variables, including geographic, climatic, topographic, and soil properties, for their correlation with volume growth. We estimated the optimal conditions for yellow poplar growth by averaging the values of the variables for the top five performing stands. To calculate the relative distance of any stand from the optimal conditions, we divided the difference between the stand's values for the environmental variables and the optimal conditions by the standard deviation of those variables. We then calculated Spearman rank correlation coefficients between these distances and volume growth rankings. Wind exposure (WE), growing season temperature (GT), Latitude (LN), soil phosphorus pentoxide (P2O5) content, low extreme temperature during January and February (LT), and spring humidity (SH) were the most important environmental factors governing growing sites for yellow poplar in Korea, with WE being the most critical. Some variables showed synergistic effects and correlated slightly more strongly with volume growth when combined with the WE variable. Our study provides crucial insights for optimizing plantation management and site selection in non-native ranges, enhancing overall success in establishing yellow poplar plantations in South Korea. [ABSTRACT FROM AUTHOR]

Invasive exotic plants are one of the most challenging problems facing forest land managers. Many invasive species are shade intolerant and typically do not invade forest sites with dense tree canopies. In contrast, Asiatic bittersweet (Celastrus orbiculatus Thunb.), a shade-tolerant exotic liana, is capable of colonizing and successfully growing in forest sites and has proven to be an aggressive competitor of native vegetation in the eastern USA. We investigated changes in the presence and cover of bittersweet after a hurricane-created major canopy disturbance in a southeastern USA upland hardwood forest over 20 yr. Bittersweet was present frequently in mesic but rarely in xeric forest sites. Bittersweet increased rapidly for the first 9 yr after a hurricane within disturbed sites; its presence then increased slowly to year 20. Bittersweet was more frequently found within versus outside wind-felled tree gaps; its presence was greater west and south of gap centers within gaps but was greater east and north of centers outside gaps in the unaffected forest. We attributed these location-based differences in presence to differences in available soil moisture. Bittersweet was present in extremely low light environments. As with presence, the rate of increase in bittersweet cover slowed 9 yr after a hurricane. Results of this long-term study will provide forest managers with information to evaluate the potential response of bittersweet to forest management treatments such as timber harvest. [ABSTRACT FROM AUTHOR]

Landslides are a common geodynamic phenomenon that cause substantial life and property damage worldwide. In the present study, we developed models to evaluate landslide susceptibility in forest-covered areas in Lin'an, southeastern China using logistic regression (LR), decision tree (DT), and random forest (RF) techniques. In addition to conventional landslide-related natural and human disturbance factors, factors describing forest cover, including forest type (two plantations (hickory and bamboo) and four natural forests (conifer, hardwood, shrub, and moso bamboo) and understory vegetation conditions, were included as predictors. Model performance was evaluated based on true-positive rate, Kappa value, and area under the ROC curve using a 10-fold cross-validation method. All models exhibited good performance with measures of ≥0.70, although the LR model was relatively inferior. The key predictors were forest type, understory vegetation height (UVH), normalized differential vegetation index (NDVI) in summer, distance to road (DTRD), and maximum daily rainfall (MDR). Hickory plantations yielded the highest landslide probability, while conifer and hardwood forests had the lowest values. Bamboo plantations had probability results comparable to those of natural forests. Using the RF model, areas with a shorter UVH (<1.2 m), a lower NDVI (<0.70), a heavier MDR (>115 mm), or a shorter DTRD (<500 m) were predicted to be landslide-prone. Information on forest cover is essential for predicting landslides in areas with rich forest cover, and conversion from natural forests to plantations could increase landslide risk. Across the study areas, the northwestern part was the most landslide-prone. In terms of landslide prevention, the RF model-based map produced the most accurate predictions for the "very high" category of landslide. These results will help us better understand landslide occurrences in forest-covered areas and provide valuable information for governments in designing disaster mitigation. [ABSTRACT FROM AUTHOR]

Reforestation practices have intensified in the Mississippi Alluvial Valley (MAV) of the United States of America with the aid of Farm Bill programs during the past three decades. Increases in reforested land also enhance possibilities to restore once-abundant but currently sparse species, such as eastern wild turkeys (Meleagris gallopavo silvestris) in the MAV. However, it is unknown whether <20-year-old hardwood regeneration provides a suitable habitat for re-establishing wild turkey populations in the MAV. We translocated wild turkeys to two study sites in reforested areas of the MAV. We monitored 74 wild turkeys' habitat use and resource selection using radio telemetry from February 2009 to June 2010. We developed land use and land cover maps for the resource selection analysis of translocated wild turkeys. We found that turkey habitat use varied by site, sex, season, land cover type, and distance to mature hardwoods. Habitat use by wild turkeys decreased as distance to mature hardwood forest increased. Female wild turkeys used more hardwood regeneration during nesting and post-nesting seasons than during pre-nesting seasons. Although wild turkeys did not use regenerating and mature hardwood forests to the same extent, management of these forests appears critical to restoring wild turkeys in the MAV. [ABSTRACT FROM AUTHOR]

Detailed information on amphibian assemblages associated with high-elevation (>1000 m above sea level) bogs in southwest Virginia's Balsam Mountains is lacking in the literature, with few historic surveys focused on these habitats. We compared amphibian diversity at two such bogs in Grayson Highlands State Park during 2021 and 2022, finding 11 total amphibian species and 172 total individuals. Amphibians at both sites were restricted to salamanders typically associated with headwater stream and seep communities and adjacent forests, with no anurans or poolbreeding salamanders observed. Assemblages also varied between sites, which were similar in wetland character but located within differing upland contexts. Desmognathine salamanders dominated encounters at a bog nested within heavily-disturbed, cleared bald habitat, with a more diverse assemblage containing several species adapted to high-elevation forests found at a nearby site nested within northern hardwood and spruce-fir forests. We additionally uncovered several Weller's Salamanders (P. welleri) at the latter site, confirming the species' presence in Grayson Highlands State Park and expanding its habitat associations to sphagnum substrate within highelevation bogs. Our dataset provides a preliminary inventory of amphibians from this understudied habitat type and a foundation for more detailed investigation into habitat associations of individual species of concern. [ABSTRACT FROM AUTHOR]