Red Maple Research Articles

Bark and crown morphology drive differences in rainwater distribution in an upland oak forest

Throughout the central and eastern US, the composition and structure of upland oak (Quercus) forests are changing. These changes are in part due to fire exclusion, whereby shade-tolerant, often fire-sensitive tree species are gaining a competitive edge over relatively shade-intolerant, fire-adapted oaks. This shift has been hypothesized to occur via a positive feedback termed mesophication, whereby encroaching tree species (‘mesophytes’) create dense, shaded understory conditions that limit oak regeneration and create cooler and wetter microclimates that decrease forest flammability. The change in canopy composition and structure may also impact hydrologic inputs by redistributing rainfall via throughfall and stemflow. To assess the extent of this redistribution by mesophytes compared to oaks and the net impact to forest floor moisture availability, we monitored throughfall, stemflow, and surface soil moisture at depths of 7.6 cm, 12.0 cm, and 20.0 cm near the bole, mid-crown, and crown edge monthly over a 14-month period. Measurements were made across seasons in both the midstory and overstory canopy strata, including oak (Q. alba, Q. falcata) and non-oak species that are increasing in relative abundance in midstory canopy strata in northern Mississippi (Carya tomentosa, Acer rubrum, Ulmus alata). Non-oak species in the midstory (A. rubrum, U. alata) had smoother bark that led to more than three-times larger stemflow generation and more than two-times larger throughfall generation per basal area compared to oak species. However, there was mixed response to soil moisture, with both non-oak (A. rubrum) and oak (Q. falcata) species having wetter than average volumetric water content compared to all other midstory species. Overstory C. tomentosa generated 2.7-times larger stemflow volume than Q. alba while Q. alba generated the largest throughfall volume. Although overstory A. rubrum generated intermediate volumes of throughfall and stemflow, the cumulative effect led to wetter than average soils compared to all other overstory species. These findings suggest that the hydrologic partitioning by mesophyte crowns may serve as an additional mechanism by which encroaching non-oak species act to reduce forest flammability and promote conditions favorable for their own regeneration. This differential rainwater redistribution mechanism may ultimately compromise long-term oak regeneration and our ability to restore fire to fire-dependent forest ecosystems.

Ecosystem services and economic values provided by urban park trees in the air polluted city of Mashhad

Estimates of air pollutant removal by urban park trees in heavily polluted city of Mashhad, Iran, the associated economic value and the impact on air quality improvement are the main contributors of this study. The economic value of Mellat Park is substantial with a benefit-cost ratio at 0.6; however, the design of Mellat Park has not been adopted in accordance with air quality condition. While carbon emissions is not substantial, a significant part of Mellat Park's value (53.5 %) arises from carbon sequestration. Regarding PM2.5, the most harmful air pollutant, there was a decline in air quality. The economic analysis of the park's three most frequent and three most valuable species highlights the inconsistency between the tree species and the environmental demands. If Acer rubrum (the most valuable species) or Paulownia (the second most valuable species) had been planted rather than Platanus orientalis (the most common species), the park's tree value would have seen 2.7 times increase and a 41.8 % boost. Local scale design considering the link between air pollution and vegetation configuration -including landscape for vegetation and superior plant species - can maximize value of the park's trees on removal rates and air quality improvement.

Assessing the influence of simulated ice storm-induced crown damage on nonstructural carbohydrates, wound closure, and radial growth of maple trees

We evaluated shoot nonstructural carbohydrate (NSC) concentrations, stem wound closure, and radial growth of sugar maple ( Acer saccharum Marsh.) and red maple ( Acer rubrum L.) trees in a novel ice storm experiment in which five storm treatments (0, 6.4, 12.7, and 19.1 mm of radial ice accretion in 1 year and 12.7 mm of ice in two consecutive years) were applied within a mature northern hardwood forest. We tested for changes in physiology at two levels: (1) associated with plot-level ice treatments and (2) with crown damage classes of individual trees. Few differences in NSC or wound closure associated with treatment were found. Growth decreased for red maple in the medium and high treatments and sugar maple in the high treatment but no other treatments. Changes in physiology were more evident when assessed using crown damage classes. Two NSC components were elevated in sugar and red maples with high (≥50%) crown damage. Wound closure was less for red maples with high damage, and separation among damage classes was even greater for sugar maple. Red maples with moderate (<50%) and high crown damage showed gradually declining growth, whereas sugar maples with high damage showed ∼80% reduction in growth the first year after injury.

Immunotoxicological, histopathological, and ultrastructural effects of waterborne pyrogallol exposure on African catfish (Clariasgariepinus)

Pyrogallol is a naturally occurring polyphenol derived from natural plants, such as Acer rubrum and Eucalyptus sp. The current study was designed to evaluated pyrogallol-mediated toxicity at sublethal levels (1, 5, and 10 mg/L), derived from 96 h-LC50 values previously determined for African catfish (Clarias gariepinus). Immunotoxicological indices, histological, histochemical, and ultrastructural alterations in C. gariepinus were evaluated following a 15-day pyrogallol exposure. Pyrogallol decreased immune parameters [lysozyme activity (LYZ), immunoglobulin M (IgM), and phagocytic activity] and increased pro-inflammatory cytokines, interleukin-1 beta (IL-1β), interleukin-6 (IL-6) in the serum of C. gariepinus. In addition, histopathology analysis demonstrated that exposure to pyrogallol induced injury in the liver and spleen of fish. Cellular changes in the liver include hepatocyte hydropic degeneration, melanomacrophage, vacuolated hepatocytes, congested blood, severe structural deformation, and hemorrhage. In the spleen, ellipsoid structures, melanomacrophage centers, and infiltration of inflammatory cells were evident. Together, a high frequency of histopathological lesions was scored in both the liver and spleen of C. gariepinus, which showed a dose-dependent relationship between pyrogallol exposure and histopathological indices. Our data suggest that dysfunction in the immune system may be mediated by pyrogallol-induced changes in cytokines.

Lire le passé forestier dans un bourbier : histoire écologique et dynamique contemporaine d’une population marginale nordique d’érable rouge (Acer rubrum)

ABSTRACT Populations at the edge of a species range are vulnerable to climate change. Studying their ecological history helps understanding resilience processes acting at the limit of the species’ tolerance envelope. In the mixedwood forest ecotone, several thermophilic species, such as white pine and red maple, reach the northern limit of their geographical range. Here we rely on macrofossil analysis of charcoal particles and plant macroremains of a forest hollow to reconstruct the local history of thermophilic species in a marginal red maple stand isolated within the mixedwood forest ecotone. Taxonomic identification and radiocarbon dating of charred particles and wood remains extracted along the peat accumulation profile indicated dominance of white pine during the Holocene Climate Optimum (6200 to 4300 cal yr BP). The fossil assemblage suggests the transition of a black spruce - feathermoss (>9500 to 6200 cal yr BP) to a balsam fir forest that developed after the decline of white pine (since 4300 cal yr BP). Red maple is not detected in the fossil assemblage suggesting a late arrival and/or expansion on the site, likely favored by anthropogenic activities and the climate warming ongoing since the end of the Little Ice Age.

Physical and physiological pathways of off-target triclopyr movement and associated non-target injury following basal bark application

AbstractBasal bark treatment with triclopyr butoxyethyl ester is used to control woody invasive plants, including Brazilian peppertree (Schinus terebinthifolia Raddi). However, the ester formulation cannot be applied where standing water is present, which includes wetlands where S. terebinthifolia is found. In 2009, a low-volatile acid formulation of triclopyr was labeled for use in aquatic sites, which allows for basal bark applications when standing water is present. This formulation may have utility for controlling woody plants in standing water. However, anecdotal observations of injury to non-target plants following applications during periods of inundation have been reported. To address this, mesocosm studies were conducted to assess non-target injury through triclopyr root exudation or release from the surface of treated stems via flooding. Mesocosms contained S. terebinthifolia as the treated target, while sugarberry (Celtis laevigata Willd.), buttonbush (Cephalanthus occidentalis L.), and red maple (Acer rubrum L.) were included as non-targets. In the first study, the pathway of root exudation for non-target injury following triclopyr (34 g L−1) basal bark application was isolated with activated charcoal placed at the soil surface. In the second study, mesocosms were flooded to assess triclopyr release from the surface of treated stems and subsequent non-target injury. Defoliation of non-target species posttreatment was ≤8%, and triclopyr was detected at ≤5 µg L−1 in mesocosm wells when activated charcoal was present. Posttreatment non-target defoliation up to 92%, coupled with triclopyr concentrations in surface waters and wells as high as 4,637 µg L−1, indicated triclopyr movement as a result of flooding. Additionally, triclopyr non-target injury from soil activity independent of flooding was observed. These findings provide limited evidence of triclopyr root exudation but considerable evidence of triclopyr release during flooding following basal bark treatment and support a cautionary approach to basal bark application when standing water is present.

Scientific opinion on the renewal of the authorisation of Scansmoke SEF7525 (SF-004) as a smoke flavouring Primary Product.

The EFSA Panel on Food Additives and Flavourings (FAF) was requested to evaluate the safety of the smoke flavouring Primary Product Scansmoke SEF7525 (SF-004), for which a renewal application was submitted in accordance with Article 12(1) of Regulation (EC) No 2065/2003. This opinion refers to the assessment of data submitted on chemical characterisation, dietary exposure and genotoxicity of the Primary Product. Scansmoke SEF7525 is obtained from a tar produced from a mixture of red oak, white oak, maple, beech and hickory. Based on the compositional data, the Panel noted that the identified and quantified proportion of the solvent-free fraction amounts to 32.6 weight (wt)%, thus the applied method does not meet the legal quality criterion that at least 50% of the solvent-free fraction shall be identified and quantified. At the maximum proposed use levels, dietary exposure estimates calculated with Food Additive Intake Model (FAIM) ranged from 0.6 to 3.8 mg/kg body weight (bw) per day at the mean and from 1.1 to 10.1 mg/kg bw per day at the 95th percentile. Based on the available information on genotoxicity on 44 identified components, the Panel concluded that two substances in the Primary Product, styrene and benzofuran, raise a potential concern for genotoxicity. In addition, a potential concern for genotoxicity was identified for the unidentified part of the mixture. Considering that the exposure estimates for styrene and benzofuran are above the threshold of toxicological concern (TTC) value of 0.0025 kg/kg bw per day for DNA-reactive mutagens and/or carcinogens and since further data are needed to clarify their potential genotoxicity, the Panel concluded that the potential safety concern for genotoxicity of the Primary Product cannot be ruled out.

Forecasting the partial cutting cycle for Québec yellow birch-conifer mixedwood stands

Since the mid 1990s, partial cuts have been widely used in yellow birch–conifer stands (BJR, bétulaies jaunes résineuses) in the temperate forests of Québec. We studied the impact of residual basal area on stand composition and on the time required to reconstitute enough merchantable basal area to allow for a second partial cut, according to the usual standards of forest management in Québec. To do so, we used a dataset from 9 experiments as well as simulations of the Artémis-2014 growth model and those of a new model, BJR, which we calibrated using the study data. Our results show that residual basal area influences stand periodic annual increment, which peaks 10 to 15 years after the cut. Residual basal area also influences the length of the cutting cycle and future stand composition. We estimated a mean cutting cycle of 24 years for a mean residual basal area of 18 m2·ha-1, and of 40 years for a mean residual basal area of 14 m2·ha-1. For the latter, our results also show that some opportunistic species of lesser commercial value, such as red maple, could become more abundant.

Spatial variability of urban forest topsoil properties: towards representative and robust sampling design.

Background: Soil spatial variability is a major concern when deciding how to collect a representative topsoil sample for laboratory analysis. Sampling design to capture site-specific variability is documented in the agricultural literature, but poorly understood for urban forest soils where soils may be characterized by strong horizontal and vertical variability and large temporal anthropogenic disturbances. Methods: This paper evaluates the spatial variability of selected topsoil properties under urban trees to define a statistically robust sampling design that optimizes the number of samples to reliably characterize basal soil respiration (BSR), a property associated with soil health. To provide a reference on variability, two additional soil properties were measured, unrelated to BSR: electrical conductivity (EC) and bulk density (BD). Thirteen sampling sites comprising both park and street trees ( Acer rubrum) were selected in Cambridge, MA, USA. Results: Results indicate street tree topsoil had approximately twice as much variation, requiring more intensive sampling, as did park tree topsoil, even though street trees had smaller soil sampling zones, constricted by tree pits. The variability of BSR was nearly identical to that of EC, and BD results varied least. A large number of samples would be required for acceptable levels of statistical reliability (90% CI - 10% ER) of 44.4, 41.7, and 6.4 for BSR, EC, and BD, respectively, whereas by accepting a lower level of certainty (80% CI - 20% ER) the number of required soil samples was calculated as 6.8, 6.4, and 0.4 for BSR, EC, and BD, respectively. Conclusions: The use of EC testing as a baseline measure to determine spatial variation in the topsoil is proposed, to alleviate the financial implications of more expensive BSR testing. Factors of topsoil disturbance and soil access restrictions at sites with severe root-sidewalk conflicts and the overall generalizability of the results are also discussed.

Fine root decomposition and macronutrient release in temperate forests: Examining the litter bag and intact soil core approaches and their relationship with fungal community composition

Accurate measurement of decomposition of fine roots in forests is important for understanding nutrient cycling, carbon dynamics and biotic responses; however, various sources of error or bias interfere with commonly used approaches. Most studies of fine root decomposition have used the buried root litter bag method, but this method may underestimate decay rates based on comparisons with the less disruptive, intact soil core approach. We compared these two methods for one year for seven temperate forest trees growing in twelve monospecific plantations in central New York. The experimental design included four species that form arbuscular mycorrhizae (sugar maple, red maple, cherry, tulip poplar) and three with ectomycorrhizae (pine, spruce, oak). We also examined macronutrients (N, P) release and fungal community composition of decaying fine roots using Illumina sequencing. Across the seven species and 12 plots, fine root decay rate was significantly higher for intact cores than litter bags, with the difference being approximately 12 %, a smaller disparity than that observed in previous comparisons. However, one species (Norway spruce) showed the opposite trend. Similarly, N and P release from decaying roots was significantly greater for the intact core method, but again with an exception (red oak). No consistent effects of mycorrhizal type on the method effect or decay rate and nutrient release were detected. Fungal communities in decaying roots differed between the two methods; nevertheless, Mycena spp. dominated most plots for both methods. These results further emphasize the notion that decay rates and nutrient mobilization of fine roots in forests are usually underestimated by the litter bag approach.

First report of Epicoccum latusicollum causing leaf spot disease on red maple (Acer rubrum L.) in China: Insights from a sentinel planting garden

Red maple (Acer rubrum L.), a tree species native to North America, has been introduced and widely cultivated for timber and ornamental purpose in China. In May 2021, black-brown leaf spots were observed on 3-year-old red maple saplings in a sentinel planting garden located in Lishui district, Jiangsu Province, China. This disease reduces not only the growth but also the ornamental value of affected trees. From symptomatic red maple leaves, three fungal isolates were recovered and subjected to pathogenicity tests by inoculating healthy leaves with mycelium plugs. The isolate EL.1 induced leaf disease successfully with symptoms like those observed in the field, and it was subsequently re-isolated from infected leaves. On PDA media, isolate EL.1 produced spherical brown pycnidia, and its colony displayed a transition from white to grayish with reddish-brown diffusible pigments. Ellipsoidal hyaline conidia were observed. The morphological characteristics of this fungus matched those of Epicoccum spp. For accurate identification, partial sequences of the internal transcribed spacer region (ITS), TUB2 and RPB2 genes were amplified and sequenced. Phylogenetic analysis verified the species as Epicoccum latusicollum. This marks the first record of E. latusicollum on red maple and emphasizes the vital role of sentinel gardens in elucidating novel pathogen-plant host relationships.

Tree species richness around urban red maples reduces pest density but does not enhance biological control

Urban trees often host greater insect pest abundance than trees in rural forests. This may be due, in part, to differences in tree diversity and canopy cover between these settings. Urban trees are often planted in isolation or monoculture, which favors pest accumulation. Gloomy scale, Melanaspis tenebricosa Comstock, is a pest of urban red maples (Acer rubrum L.) that is abundant where impervious surfaces dominate the local landscape. Increasing tree diversity and canopy cover around urban red maples may reduce gloomy scale abundance by supporting natural enemy communities. We investigated the effect that surrounding tree species richness and tree canopy cover had on gloomy scale abundance, natural enemy abundance, and biological control in red maple trees in Raleigh, NC, USA. We collected scales and natural enemies from red maples that spanned a gradient of tree species richness, canopy cover, and impervious surface values. We also measured gloomy scale parasitism and predation of sentinel prey in red maple canopies. Greater tree species richness and canopy cover were associated with lower gloomy scale density. Red maples in diverse settings also hosted fewer scales per natural enemy. Parasitoids were less common in maples in diverse settings, but generalist predator abundance was unaffected by tree diversity. Finally, tree species richness and canopy cover did not increase biological control of scales or sentinel prey. Our findings suggest that higher tree diversity and greater canopy cover may reduce gloomy scale density, but this is not entirely explained by the effects of natural enemies and biological control.

Documenting Two Centuries of Change in Longleaf Pine (Pinus palustris) Forests of the Coastal Plain Province, Southeastern USA

While many tree species occur across the Coastal Plain of the southeastern United States, longleaf pine (Pinus palustris C. Lawson) savannas and woodlands once dominated this region. To quantify longleaf pine’s past primacy and trends in the Coastal Plain, we combined seven studies consisting of 255,000 trees from land surveys, conducted between 1810 and 1860 with other descriptions of historical forests, including change to the present day. Our synthesis found support that Pinus palustris predominantly constituted 77% of historical Coastal Plain trees and upland oaks (Quercus) contributed another 8%. While Pinus still dominates these forests today (58% of all trees), most are now either planted loblolly (Pinus taeda L.) or slash (Pinus elliottii Engelm.) pines. Water oak (Quercus nigra L.), live oak (Quercus virginiana Mill.), sweetgum (Liquidambar styraciflua L.), and red maple (Acer rubrum L.) have increased their proportions compared to historical surveys; both longleaf pine and upland oaks have declined to ≤5% of all trees. Our work also supports previous estimates that longleaf pine originally dominated over 25–30 million ha of Coastal Plain forests. As late as the early 1900s, longleaf pine may still have covered 20 million ha, but declined to 7.1 million ha by 1935 and dropped to 4.9 million ha by 1955. Longleaf pine’s regression continued into the mid-1990s, reaching a low of about 1.3 million ha; since then, restoration efforts have produced a modest recovery to 2.3 million ha. Two centuries of overcutting, land clearing, turpentining for chemicals, fire exclusion followed by forest densification by fire-sensitive species, and other silvicultural influences, including widespread loblolly and slash pine plantations, have greatly diminished the Coastal Plain’s once extensive open longleaf pine forests.

Seasonal activity of spotted lanternfly (Hemiptera: Fulgoridae), in Southeast Pennsylvania.

The spotted lanternfly, Lycorma delicatula (White, 1845), is an invasive species in the United States. This pest causes damage to vineyards and has the potential to negatively affect other crops and industries. Information describing the seasonal timing of life stages can improve its management. In 2019 and 2020, spotted lanternfly seasonal activity was followed weekly from spring egg hatch to the first hard freeze. Weighted mean timing of activity for each nymphal instar, early adults, late adults, total adults, and egg mass deposition are presented for 2019 and 2020 on Acer rubrum and 2020 on Ailanthus altissima. Logistic equations describing the percentage completion of each activity period on these hosts were fitted using a start date of 1 January to calculate accumulated degree days (ADD). For the adult and egg mass deposition periods, we additionally used a biofix of the date adults were first observed to calculate ADD. ADD from 1 January adequately estimated the timing of nymphal instars but ADD from observation of the first adult better estimated the timing of adult activity and egg mass deposition. Late adult activity and egg mass deposition periods appeared to be influenced by another environmental cue, such as day length. Maps of season-long ADD show that spotted lanternflies are unlikely to reach adulthood in colder regions of the northeast United States, and therefore may not establish there. We also report a strong seasonal trend in sex ratio on A. rubrum, where the population shifted from over 80% male to over 80% female in October.

Dendrochronology reveals different effects among host tree species from feeding by Lycorma delicatula (White).

The spotted lanternfly, Lycorma delicatula (White) (Hemiptera: Fulgoridae), was first detected in the United States in Berks County, Pennsylvania, in 2014. Native to China, this phloem-feeding planthopper threatens agricultural, ornamental, nursery, and timber industries in its invaded range through quarantine restrictions on shipments, as well as impacts on plants themselves. The long-term impacts of L. delicatula feeding on tree species have not been well studied in North America. Using standard dendrochronological methods on cores taken from trees with differing levels of L. delicatula infestation and systemic insecticidal control, we quantified the impact of L. delicatula feeding on the annual growth of four tree species in Pennsylvania: Ailanthus altissima, Juglans nigra, Liriodendron tulipifera, and Acer rubrum. The results suggest that L. delicatula feeding is associated with the diminished growth of A. altissima, but no change was observed in any other tree species tested. The results also suggest that systemic insecticides mitigate the impact of L. delicatula feeding on A. altissima growth.

Fire exclusion vs. a fire-free interval following repeated prescribed fire: Consequences for forest stand structure and species composition in an upland oak forest

In the Central Appalachian forest region, oaks (Quercus L.) and other disturbance-dependent tree species are experiencing widespread regeneration failure after decades of fire suppression. Managers use prescribed fire to decrease basal area with the aim of facilitating oak regeneration and shifting species composition toward pyrophytic species that dominate the overstory. Although fire may set the stage for improved oak regeneration, a fire-free period is necessary for oak seedlings to develop into fire-resistant stems. The effects of prescribed fire have been amply investigated across the region, but few studies have examined changes to stand structure and oak regeneration after cessation of burning. We followed the effects of three treatments, fire-excluded, 3x-burned, and 4x-burned, for 20 years. After a fire-free interval of approximately ten years, burned treatments had significantly lower total basal area and greater relative density of oaks in the subcanopy (10–20 cm DBH) than the fire-excluded treatment. The 4x-burned, which had the greatest reduction in basal area, also had greater relative density of midstory oaks (2–10 cm DBH), and higher stem density of oak regeneration (<2 cm DBH) than the fire-excluded. Despite these trends towards increased regeneration of oaks and other pyrophytes, red maple (Acer rubrum L.) stem density also increased in the midstory of burned treatments, suggesting a legacy effect of decades of fire suppression and the concomitant mesophication that has occurred. We also examined the effects of continued fire exclusion on the fire-excluded reference treatment. Additional evidence of mesophication on this treatment was demonstrated by increased overstory (≥20 cm DBH) and subcanopy red maple stem density as well as midstory (2–10 cm DBH) eastern white pine (Pinus strobus L.) stem density, a prominent mesophyte on these sites. This study supports the idea that repeated prescribed burning followed by a 10-year fire-free interval can alter stand structure and lead to improved oak regeneration by increasing canopy openness. However, the results were variable across burned treatments (3x vs. 4x) and the ingrowth of red maple and other mesophytes after only 10 years of fire exclusion will require additional control measures. Successful maintenance of oak-dominated forests on upland sites in the Central Appalachian hardwoods region may be contingent on a subsequent canopy disturbance that further increases light availability followed by a fire-free interval. Importantly, in the absence of burning or other disturbance, red maple and other mesophytic species will continue to increase in relative stem density.

The Acadian Forest of New Brunswick in the 21st century: what shifting heat and water balance imply for future stand dynamics and management

Climate change is altering the dynamics of New Brunswick’s forests. To mitigate the effects of climate change, it is crucial to account for future uncertainties in climate projections and natural disturbance trajectories when designing forestry practices. This paper presents the projected changes in key climatic drivers for New Brunswick’s forests, examines the impacts of climate change on forest stand dynamics, and reviews adaptive silviculture tools for climate change adaptation. By 2071–2100, a projected 4–6 °C increase in mean annual temperature will lead to a 39%–77% rise in growing degree-days and a reduction in summer atmospheric water balance by 48–79 mm across New Brunswick. Foresters should anticipate a doubling of annual area burned, the northward migration of spruce budworm ( Choristoneura fumiferana (Clemens)), and the introduction of novel insects and diseases. Forest simulation models project a severe decline in boreal tree species abundance, including a 50% decline in balsam fir ( Abies balsamea (L.) Mill) and black spruce ( Picea mariana (Mill.) Britton et al.), offset by an increase in temperate species, notably red maple ( Acer rubrum L.; +200%) and American beech ( Fagus grandifolia Ehrh; +135%). Forests in the highlands and lowlands ecoregions, with 40%–50% and 15%–30% spruce and balsam fir composition, respectively, are particularly vulnerable. To limit climate change effects on forest values, foresters must prioritize climate resiliency in their management plans. Strategies should ensure the steady provision of forest goods and services under changing climatic conditions. Forest thinning enhances stand productivity and resilience, while shelterwood and two-age harvest balances timber production with diversity. Clearcutting, despite drawbacks, establishes younger, more vigorous forests with higher carbon sequestration potential. Assisted migration offers promise in helping threatened tree species adapt. Climate change will have a significant impact on New Brunswick’s forests, leading to changes in key climatic drivers, increased risks of disturbances, and a shift toward more temperate tree species. However, there are existing adaptation strategies available. It is crucial to consider future uncertainties when designing and evaluating forestry practices, as this is essential for mitigating the effects of climate change on forest values and ensuring the continued provision of forest goods and services over time.

First Report of Root Rot of Redbud Caused by Phytopythium vexans in Tennessee and the United States.

The eastern redbud (Cercis canadensis L.) is an esthetically and economically important landscape tree with vibrant blossoms and attractive heart-shaped leaves. One-year-old eastern redbud seedlings grown in field condition in two commercial nurseries in Warren Co., Tennessee exhibited severe root rot in October 2021. Dark brown to black lesions and rot were observed in the affected roots (Fig. 1a). Disease severity was 50-75% of root area and disease incidence was approximately 30-40% of 10,000 plants. Surface sterilized (10% NaOCl; 1 min) symptomatic tissues were plated on V8-PARPH and incubated at 25°C. Whitish cottony mycelia with radiate and chrysanthemum flower-like growth patterns were observed within 4 days of incubation. Subglobose papillate sporangia (10.24 to 20.98 µm, n=50), filamentous to globose smooth oogonia, bell-shaped antheridia and spherical zoospores that are characteristic of Phytopythium vexans (de Cock et al. 2015) were observed in older cultures that were subjected to specific growth conditions as previously described by Ghimire & Baysal-Gurel (2023). Pathogen identification was confirmed by extracting total DNA using the DNeasy PowerLyzer Microbial Kit from 7-day-old cultures of isolates FBG0874, FBG1998, FBG2009 grown on V8-PARPH. P. vexans specific LAMP assay was conducted for the rapid molecular screening and confirmation of the isolates (Ghimire et al. 2023). Primer pairs ITS1/ITS4 (White et al. 1990), NL1/NL4 (Baten et al. 2014), Levup and Fm85mod (Robideau et al. 2011) were used to amplify and sequence the internal transcribed spacer (ITS), 28S large subunit (LSU) of ribosomal RNA and the cytochrome c oxidase subunit I (CoxI) of mitochondrial DNA genetic markers, respectively. The sequences (GenBank accession nos. OR204701, OR205212, OR205213: ITS; OR205214, OR205215, OR205216: LSU; OR220805, OR220806, OR220807: CoxI) were 100% similar to ITS, LSU, and CoxI genetic markers of P. vexans isolates in the NCBI database (MK011121: ITS, KX092469: LSU and KT692908: CoxI). Pathogenicity tests were performed on one-year-old eastern redbud seedlings grown in 1 gal containers to fulfill Koch's postulate. Eastern redbud seedlings were drench inoculated (150 ml/plant) with pathogen slurry (two plates of 7-day-old culture/liter) (Panth et al. 2021) of isolates FBG0874, FBG1998, and FBG2009 (five plants/isolate). Control plants were drenched with agar slurry without pathogen. The study was conducted in a greenhouse maintained at 21 to 23°C, 70%RH, with 16-h photoperiod and irrigated twice a day for 2 min using an overhead irrigation system. Fourteen days after inoculation dark brown to black lesions developed in the root of all inoculated plants that were identical to the symptoms observed in the original samples (Fig. 1b), while the roots of non-inoculated plants remained asymptomatic (Fig. 1c). Isolates resembling P. vexans morphological characteristics were recovered from inoculated plants, and their identity was confirmed as P. vexans using LAMP assay. P. vexans has been previously reported to cause root and crown rot in flowering cherry, ginkgo, and red maple in Tennessee (Baysal-Gurel et al. 2021, Panth et al. 2021). To our knowledge, this is the first report of P. vexans causing root rot of eastern redbud in Tennessee and the United States. Identification of this pathogen as the causal agent is important in designing and implementing effective management practices to mitigate this threat to redbud production.

Current management in national and state forests has important but limited impacts on sustaining oaks in temperate forests of the eastern U.S

Active management for promoting oaks (Quercus spp.) and restraining maples (Acer spp.) is mostly conducted in public forests (e.g., national forests [NF] and state forests [SF]) because of oaks' ecological and economic importance. Studies have shown that current management efforts have limited success, meanwhile, oak-dominant forests continue to shift in composition and structure to shade-tolerant, fire-sensitive mesophytic species (e.g., red maple A. rubrum). It remains to be evaluated whether current management can achieve its objectives in public forests and at regional scales. In this study, we investigated the long-term outcomes of business-as-usual (BAU) and alternative management (AltMgt) scenarios in a large, temperate hardwood forest landscape in southern Ohio, US. The BAU approach simulates contemporary management, informed by harvest records across public lands and a geospatial disturbance database (i.e., LANDFIRE) to infer private land management. Whereas the AltMgt scenario increases the pace and scale of forest management on public lands through two-stage oak shelterwood harvests, treated every ten years across 10% of the land area with private land remaining as BAU. We used a spatially explicit and dynamic forest landscape model to project species compositional and structural changes under these two scenarios. Our results demonstrate that BAU management in public forests may not successfully sustain oak but instead favors the colonization of maples. Further, management objectives to promote oaks could be achieved on public forests under the AltMgt scenario, but such alternative management had limited impacts at the regional scale when including private lands. The management of NF and SF has a crucial role in driving regional changes in oak and maple abundance, particularly when private lands continued their BAU management. Starting conditions by landownership are also important considerations for oak-maple dynamics through time, implying the need to have a range of priorities and objectives, under different time frames, when developing long-term conservation plans for oak forests at regional-scales.

Seed coatings containing capsaicin reduce seed removal in temperate woody species

Coating seeds in taste-averting chemical defenses (e.g., capsaicin from Capsicum spp.) can reduce rodent seed predation, and thus might promote plant establishment and forest regeneration. However, the efficacy of such seed coatings remains unknown for many woody plant species, and seed coatings have not been evaluated across different habitats where forest managers might seek to promote forest regeneration. We used two complementary seed-removal experiments in closed-canopy forests (Michigan) and an old field undergoing reforestation (New York) to examine whether coating seeds of four native tree species ( Acer rubrum, Fagus grandifolia, Pinus banksiana, and Pinus resinosa) with chili powder reduces seed removal by rodents. In all species and habitats, control seeds were removed more than seeds treated with capsaicin (94% more in the closed-canopy forest, 17% more in the old field). Seed coatings containing capsaicin may provide a generally effective tool to support native tree recruitment and promote restoration success.