Fraser Fir Research Articles

Survey of Phytophthora Diversity Reveals P. abietivora as a Potential Phytophthora Root Rot Pathogen in Québec Christmas Tree Plantations.

Christmas trees are an economically and culturally important ornamental plant in North America. Many microorganisms are pathogens of firs cultivated as Christmas trees. Among those, Phytophthora causes millions of dollars in damage to plantations annually. In Canada, it is unknown which species are responsible for Phytophthora root rot (PRR) of cultivated Abies species. Between 2019 and 2021, soil and root samples were collected from 40 Christmas tree plantations in Québec province. We used soil baiting and direct isolation from unidentified root fragments to assess the diversity of culturable Phytophthora spp. The obtained isolates were identified using a multilocus sequencing and phylogenetic approach. A total of 44 isolates were identified, including eight P. chlamydospora, eight P. abietivora, seven P. gonapodyides, three P. gregata, six P. megasperma, and two P. kelmanii isolates, plus 10 isolates belonging to a previously unknown taxon that is phylogenetically close to P. chlamydospora and P. gonapodyides. Among the known species, P. abietivora was the most prevalent isolated species associated with trees showing aboveground PRR-like symptoms. Pathogenicity trials confirmed the pathogenicity potential of P. abietivora on both Fraser fir and balsam fir seedlings. Our study provides a first snapshot of the Phytophthora diversity in Québec's Christmas tree productions and describes multiple potential first associations between Phytophthora species and Abies balsamea and A. fraseri.[Formula: see text] Copyright © 2024 His Majesty the King in Right of Canada, as represented by the Minister of Natural Resources Canada. This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Optimizing Select Fraser Fir (Abies fraseri) Reforestation Methods within an Artificial Bald at Mount Buckley, Great Smoky Mountains National Park

Optimizing Select Fraser Fir (Abies fraseri) Reforestation Methods within an Artificial Bald at Mount Buckley, Great Smoky Mountains National Park

Developing Integrated Strategies to Address Emerging Weed Management Challenges in Christmas Tree Production

Weed control is an important aspect during the first few years of Christmas tree establishment, as weed competition directly relates to the rate of Christmas tree growth during this time. The objectives of this study were to evaluate the weed control efficacy of organic mulch and herbicide combinations and to determine their phytotoxic effects on four different species of Christmas trees during the establishment stage: Fraser fir (Abies fraseri (Pursh) Poir), blue spruce (Picea pungens Engelm.), white pine (Pinus strobus L.), and Scotch pine (Pinus sylvestris L.). Twelve weed control treatments were established in a complete randomized block design with four replications in each of five fields. Weed control treatments included cypress bark organic mulch and herbicides applied alone and in combinations as well as an untreated control. Herbicides included clopyralid, oxyfluorfen, and glyphosate. All herbicides were applied at their highest labeled rate. Data collection included visual estimations of weed control and phytotoxicity to trees at 30, 60, and 90 days after treatment (DAT). Tree growth and foliar nitrogen concentration were also measured. Mulch combined with herbicide provided 60%–100% weed control in all cases; at two farms, mulch provided a significant increase in weed control when compared to the same treatments without mulch. Combinations of mulch + clopyralid + glyphosate and clopyralid + oxyfluorfen + glyphosate resulted in the highest phytotoxicity ratings. Tree growth was decreased due to some treatments at Gobles farm, and foliar N did not differ among any of the treatments.

Combined effects of water stress and fertilization on the morphology and gas exchange parameters of 3-year-old Abies fraseri (Pursh) Poir

Combined effects of water stress and fertilization on the morphology and gas exchange parameters of 3-year-old Abies fraseri (Pursh) Poir

Managing Cone Formation and Leader Growth in Fraser Fir Christmas Tree Plantations with Plant Growth Regulators

Early cone formation is a consistent issue in Fraser fir Christmas tree plantations in the eastern United States. Growers must remove cones by hand, resulting in significant labor costs, as cones degrade the aesthetic value of Christmas trees. In this study, we conducted two series of experiments in collaboration with several Christmas tree farms to determine the effectiveness of applying plant growth regulators (PGRs), specifically GA-inhibitors, in reducing cone formation and shoot growth in Fraser fir. In the first experiments we investigated the effectiveness of paclobutrazol, applied as a soil injection or as a foliar spray in reducing cone formation. The highest rate of soil application (300 mL of paclobutrazol per tree) reduced cumulative coning by approximately 38%. Leader growth control of soil applied paclobutrazol increased with application rate. In the second set of experiments, we compared four GA-inhibitors (paclobutrazol, chlormequat chloride, uniconazole-p, daminozide) applied as foliar sprays on coning and leader growth. Overall, paclobutrazol was the most effective compound for reducing coning and shoot growth. The results confirm earlier findings that application of GA-inhibitors can reduce, but not eliminate, coning. Likewise, PGR application can reduce shoot growth and possibly increase tree density but will not eliminate the need for shearing.

Gas exchange parameters of 8-year-old Abies fraseri (Pursh) Poir. seedlings under different irrigation regimes

Eight-year-old Abies fraseri seedlings were grown under different irrigation regimes to determine how drought stress might affect the seedlings in terms of gas exchange parameters. In this study, net photosynthesis (Anet), transpiration rate (E), stomatal conductance (gs), intercellular CO2 (Ci), Ci to ambient CO2 (Ca) concentration ratio (Ci/Ca), intrinsic water use efficiency (iWUE), and water use efficiency (WUE) were measured on August 11 and 27. Irrigation and measurement time were statistically significant on all gas exchange parameters except WUE for irrigation and measurement time and Anet for measurement time. E and gs were significant under the irrigation and measurement time interactions. In this study, increasing irrigation generally decreased Anet, and gs, while increased E, iWUE, and Ci/Ca. On August 27, A. fraseri had higher Anet, gs, E, Ci, Ci/Ca, and lower iWUE values than August 11. However, there was a robust positive correlation between gs and Anet, while a negative correlation between gs and iWUE in A. fraseri seedlings. In general, prolonged water deficiency leads plants to decrease Anet, gs, and E while iWUE increases, contrary to the current study. A well-developed and deeper root system, especially in plants under less or no-irrigation regimes, may alleviate drought stress effects in the long run and provide an advantage in leaf gas exchange parameters. In addition, the fact that soil moisture did not differ much between treatments, although irrigation levels were different, may explain the similar behavior among individuals measured in terms of gas exchange parameters.

Seasonal Activity Patterns of Bats in High-Elevation Conifer Sky Islands

In the southern Appalachian Mountains of the southeastern USA, bat communities in high-elevation habitats tend to be relatively under-surveyed. High-elevation habitats may provide important habitat to certain species (i.e., migratory tree bats), and may serve as climate refugia during droughts or high temperatures. We conducted an opportunistic acoustic survey of bat communities in ten survey areas in high elevation (1,585–1,920 m a.s.l.) montane Picea rubens (red spruce)-Abies fraseri (Fraser fir) forest in the southern Appalachian Mountains of western North Carolina. In each survey area, we randomly placed three full spectrum acoustic detectors (N = 30) during three seasons (spring, summer and fall) in 2015. We deployed each detector for two five-day periods during each season (n = 900 survey nights). Although we detected seven bat species/groups during the surveys, 73% of echolocation files were attributed to Lasiurus cinereus (hoary bat) and Lasionycteris noctivagans (silver-haired bat). Generally rare in the Appalachians and typically present only at low densities in the summer at mid- and low-elevations, both species were detected at all sites during all seasons. Overall, mean nightly activity of bats was higher in the summer than the spring or fall. We observed 3.7–5 times greater activity of L. cinereus in spruce-fir forests during the summer compared to spring and fall, whereas L. noctivagans had 1.3–5 times more activity in the summer compared to other seasons. After accounting for precipitation events, our finite mixture models showed that season, temperature, elevation, and canopy height influenced L. cinereus activity, whereas season and temperature affected L. noctivagans activity. Our observations suggest that high-elevation spruce-fir forests are providing summer foraging and possibly day-roosting habitat of tree bats not previously documented this far south in North America.

Sesquiterpene Induction by the Balsam Woolly Adelgid (Adelges piceae) in Putatively Resistant Fraser Fir (Abies fraseri)

Fraser fir, Abies fraseri (Pursh) Poir., is a tree endemic to the Southern Appalachians and is found only in a few isolated populations at high elevations. Fraser firs are also cultivated on a commercial scale as Christmas trees. The species is imperiled by an introduced insect, the balsam woolly adelgid, Adelges piceae Ratzeburg (BWA). The insect severely damages Christmas tree crops and has caused substantial Fraser fir mortality in natural stands. Foliar terpenoids are one mechanism of host plant defense against invading insects and may be one focus of future Christmas tree breeding efforts. This study examines the correlation of foliar terpenoids with Fraser fir performance when infested with BWA. GC-MS and GC-FID analysis of artificially infested Fraser fir foliage reveals that increased concentrations of four terpenoid compounds are associated with BWA infestations. Foliar concentrations of two sesquiterpenes, camphene and humulene, are significantly higher in putatively resistant Fraser fir clones than in more susceptible clones after sustained adelgid feeding for a period of 20 weeks. Although it is unclear if the induction of these sesquiterpenes in the host fir is directly contributing to adelgid resistance, these compounds could serve as effective indicators while screening for BWA resistance in future Christmas tree breeding programs.

Characterization of the Entomopathogenic Fungal Species Conoideocrella luteorostrata on the Scale Insect Pest Fiorinia externa Infesting the Christmas Tree Abies fraseri in the USA

We characterized the entomopathogenic fungal species, Conoideocrella luteorostrata (Zimm.) D. Johnson, G.H. Sung, Hywel-Jones & Spatafora (Hypocreales: Clavicipitaceae), on the elongate hemlock scale, Fiorinia externa Ferris (Hemiptera: Diaspididae), infesting Fraser fir Christmas tree, Abies fraseri (Pursh) Poir (Pinaceae). Fraser fir Christmas trees that were cultivated in Michigan, North Carolina, and Virginia were intercepted in Florida during plant inspection. This study is based on the isolation in pure culture, and morphological and molecular characterization using a 4-locus (ITS, LSU, SSU, tef1) and represents the first record of C. luteorostrata on F. externa. In addition, we reviewed all previously reported natural enemies of F. externa in the USA, discussed their potential as biological control agents, and concluded the need to explore a new natural enemy of F. externa. We recommend using C. luteorostrata as a biocontrol agent for F. externa. We also suggest that our isolate could be a source of new uncharacterized active compounds and could be used in the biological control of whiteflies and scale insects, as demonstrated in other C. luteorostrata strains. We also discussed the importance of investigating biological control agents in pest and pathogen interception samples.

Arthropod and Disease Management in Fraser Fir (Pinales: Pinaceae) Christmas Trees in the Southeastern United States

Abstract Fraser fir, Abies fraseri [Pursh] Poir., is one of the most desired Christmas tree species owing to its fragrance, physical appearance, and durability. This species represents a major component of the Christmas tree industry in the southeastern United States, with production occurring in North Carolina, Tennessee, and Virginia. Fraser fir production is a multi-million dollar annual industry despite growing in a limited elevational and latitudinal range. Pest management for Christmas trees is notoriously difficult owing to the near zero-tolerance of most pests, even those causing aesthetic damage. Christmas trees are produced in monocultural environments which make them highly susceptible to several arthropod and fungal pests. We review the major pests affecting Fraser fir Christmas tree production, including their biology, symptoms, and scouting procedures, and current management strategies. In general, pest management in Christmas tree production systems has not changed significantly in the last several decades, and still relies heavily on pesticide usage. We propose several areas in need of research that could help Fraser fir Christmas tree producers mitigate the impacts of climate change and potential new pest species, as well as suggest changes to current or potentially novel integrated pest management strategies which have a chance to provide economic and ecological benefits for this industry.

Представители семейства сосновые (Pinaceae Lindl.) североамериканской флоры в коллекции дендрологического сада ФБУ «СевНИИ ЛХ»

The article presents the results of the introduction of the North American flora woody species of the pine family (Pinaceae Lindl.) to the European North of Russia. The research purpose is to select the most valuable specimens for introduction into northern conditions from the tree species collection. The research has involved experimental, calculation, analytical, and comparative methods. The conclusion on the result of the introduction of a particular plant was based on the materials of long-term phenological observations, which were carried out according to the method of botanical gardens improved for the conditions of the European North of Russia. As a result of the introduction of North American species of the Pinaceae Lindl. family to the region, a large-scale test of foreign conifers was carried out for the first time; a collection of 2 species of fir, 4 species and 3 forms of spruce, 2 species of pine, and 1 species of Douglas fir was created. Most attention was paid to the introduction of species of the genus Pinus. Positive results of cultivation of Pinus contorta Loud. var. latifolia S. Wats. in the Dendrological garden allowed us to select it for further introduction testing in experimental plantations of the region. On plantations located in the Arkhangelsk and Vologda regions and the Komi Republic, 104.2 ths seedlings were grown from the seed samples, mostly from the northern natural range of this pine. Unfortunately, not all of the breeding material for the North American pine species tested was derived from natural growth sites, which puts into question some of the unsatisfactory results. Therefore, for Jack pine and Weymouth pine, it is advisable to use in testing additional samples from the most northern regions of their natural ranges in Canada. Many of these species are of both scientific and practical interest for forestry. To assess the economic value of those introduced species, adaptive capabilities of which in the conditions of the European North according to the results of studies are not in doubt, it is advisable to lay out pilot plantations in the region, similar to the already created plantings of North American lodgepole pine (Pinus contorta Loud. var. latifolia S. Wats.). The concentration of different species like balsam fir (Abies balsamea Mill.), Fraser fir (Abies fraseri (Pursch.) Poir.), American larch (Larix laricina (Du Roi) K.Koch.), Canadian spruce (Picea glauca Voss.), Engelmann’s spruce (Picea engelmannii Engelm.), black spruce (Picea mariana Britt.), Jack pine (Pinus banksiana Lamb.), lodgepole pine (Pinus contorta Loud. var. latifolia S. Wats.), and Douglas fir (Pseudotsuga menziesii Mirb.), involving several seed origins from the most northern regions of its natural range for each, in 2-3 forest areas will allow creating a valuable introduction object; scientific and practical importance of those mentioned cannot be overestimated.

Simulating stomatal response to cloud immersion for montane cloud forests in the Southern Appalachians

Montane cloud forests are incredibly biodiverse regions that exist globally at narrow elevation bands and are frequently under the presence of low-level clouds and fog. Increasing temperatures and rising cloud base heights threaten these ecosystems, and may reduce the duration of time that plants are exposed to fog. Some cloud forest species have adapted to cloud immersion and enhanced photosynthesis rates have been observed under such conditions. This manuscript tests a simple model for simulating stomatal conductance for vegetation under cloud immersion based on Jarvis's empirical formulation. The light-available energy function within the model is modified to reflect variability observed in Abies fraseri under sun, low cloud, and cloud immersed sky conditions in the Southern Appalachian Mountains. Results demonstrate that this approach captures differences amongst stomatal opening during sun, low cloud and immersed conditions for similar ranges of temperature, light, diffusivity, and xylem water potential. Simulated average stomatal conductance during cloud immersion exceeded estimates during sun and low cloud conditions by 3 and 1.5 times, respectively. The magnitude of the estimated stomatal conductance for immersed and low cloud conditions falls below experimental data under all potential environmental states. Similarly, transpiration rates estimated from modeled stomatal conductance were also lower than observed values. The larger discrepancy for cloud immersed periods highlights the need to account for plant adaptation strategies like reduced transpiration and foliar uptake that occur during cloud immersion. Simulating adaptation processes for cloud forests in modeling studies is critical in order to evaluate fully the resilience of montane cloud forest vegetation under disturbance regimes.

Assessing Megastigmus specularis (Hymenoptera: Megastigmidae) infestations in a Fraser fir (Abies fraseri (Pursh) Poir.) clonal seed orchard of the southern Appalachians

ABSTRACT The Christmas tree industry is mainly supplied with seeds from natural stands and genetically improved germplasm from clonal seed orchards (CSOs). Chalcid wasps (Megastigmus spp.) have a negative effect on the value of seedlots by reducing the quantity of viable seeds and represent a risk for national and international seed trade. Seed radiographies, field observations and seed-dissections from 25 Fraser fir (Abies fraseri (Pursh) Poir.) clones were used to determine chalcid infestation in a CSO of the southern Appalachians. We provided direct evidence that Mesopolobus cf. pinus is an ectoparasitoid of M. specularis, proposed a model that linked different aspects of the biology of these species and discussed host–insect phenological relationships. Infestation of seeds in some clones across surveys, suggested a potential genetic component to chalcid wasp's prevalence. Cold and dark rearing regimens were used to identify changes in adult insect emergence after variation of overwinter conditions. Both the frequency and the time of emerging M. specularis adults from seeds were affected by the duration of the treatments but not statistical differences were found for Mesopolobus cf. pinus. We present evidence for the efficiency of a gravity-seed cleaning method eliminating upwards of 95% of chalcid-infested seeds.

Evaluating the invasive potential of an exotic scale insect associated with annual Christmas tree harvest and distribution in the southeastern U.S.

The movement of invasive species is a global threat to ecosystems and economies. Scale insects (Hemiptera: Coccoidea) are particularly well-suited to avoid detection, invade new habitats, and escape control efforts. In countries that celebrate Christmas, the annual movement of Christmas trees has in at least one instance been associated with the invasion of a scale insect pest and subsequent devastation of indigenous forest species. In the eastern United States, except for Florida, Fiorinia externa is a well-established exotic scale insect pest of keystone hemlock species and Fraser fir Christmas trees. Annually, several hundred thousand Fraser firs are harvested and shipped into Florida, USA for sale to homeowners and businesses. There is concern that this insect may disperse from Christmas trees and establish on Florida conifers of economic and conservation interest. Here, we investigate the invasive potential of F. externa on sixteen conifer species by quantifying the reproductive potential of this insect pest and its ability to establish, reproduce, and damage these plants. We find that small amounts of heavily infested Fraser fir plant material can release several hundred juvenile F. externa for over a month. Similar to other case studies, we find evidence that host susceptibility may in part be linked to phylogenetic relatedness. Encouragingly, only six of sixteen species evaluated were susceptible to attack. Our results provide new insights into methodology for evaluating scale insect dispersal and host susceptibility. We also provide guidance for future studies investigating scale insect reproduction, dispersal, and risk for plant species of unknown susceptibility to other exotic insect pests.

Immobilized atmospheric particulate matter on leaves of 96 urban plant species.

Plants provide many ecosystem services in urban environments, including improving ambient air quality. Leaves of plants permit the deposition of particulate matter (PM) and, depending on their leaf traits, PM may be immobilized within the epicuticular wax (EW) layer, on trichomes, on hyphae of fungi, or inside stomatal cavities. In this study, leaves of 96 perennial urban plant species consisting of 45 deciduous broadleaf/needle-like trees, 32 deciduous broadleaf shrubs, 12 evergreen needle/scale-like trees, 5 evergreen broadleaf trees, and 2 climber species were investigated in June and September 2016 to determine the effectiveness of distinct leaf surfaces in PM immobilization after leaf washing treatment. The leaf surfaces were washed vigorously using a vortex shaker. The magnetizable component of accumulated and immobilized PM on the leaf surfaces was estimated using saturation isothermal remanent magnetization (SIRM) of the unwashed and washed leaves, respectively. In June, the washed leaf SIRM of deciduous (broadleaf/needle-like) tree and shrub species (n = 77) ranged between 0.1 and 13.9 μA. In September, the washed leaf SIRM of all investigated plant species (n = 96) ranged between 1.2 and 35.0 μA. Outcomes of this study indicate that leaves of Buddleja davidii, Viburnum lantana, and Sorbus intermedia showed the highest washed leaf SIRM and thus were the most effective in immobilizing PM on their leaf surfaces while leaves of Populus alba, Robinia pseudoacacia, and Abies fraseri with lowest washed leaf SIRM were the least effective. On average, more than half (i.e., 60%) of the magnetic signal still remained after vigorous washing but a large variation exists between species (9-96%). The leaf SIRM of washed leaves of deciduous broadleaf tree and shrub species was significantly higher compared to leaves of evergreen needle/scale-like species. Evidently, the magnetic signal of unwashed leaves was higher than washed ones and higher in September than in June. Leaf traits significantly influenced the magnetic signal of both washed and unwashed leaves: leaves with a high trichome density or high leaf wettability showed a higher unwashed and washed leaf SIRM compared to leaves with no trichomes or low leaf wettability. The effect of epicuticular wax structure types on leaf SIRM was indicated to be only marginally significant. Moreover, also the immobilized fraction of PM was significantly affected by trichome density and leaf wettability, thus substantiating that plant species with high trichome density and/or leaf wettability not only accumulate more PM but are also less prone to PM re-suspension than other species. In general, the results also indicate that leaf SIRM of unwashed leaves can be a good indicator to determine the effectiveness of a plant species in PM immobilization. Plant species effective in immobilizing PM on their leaf surfaces may likely improve ambient air quality when planted in urban environments. However, it is vital that leaves of these plant species (i.e., with high PM immobilization abilities) are carefully recycled as they may be polluted.

Sulfur Amendment of Soil Improves Establishment and Growth of Firs in a Field Naturally Infested with Phytophthora1

Abstract Acidification of soil from pH 6 to 4 by incorporating elemental sulfur reduced mortality and improved color and initial growth of Fraser fir, Abies fraseri (Pursh) Poir., and Canaan fir, Abies balsamea (L.) Mill. var. phanerolepis Fernald, planted into a field that had previously experienced significant losses consistent with phytophthora root rot. Acidifying the soil improved tree color starting the year of planting and persisting through five years. During their second year after planting, extension of terminal growth was 12.5 vs. 5.6 cm (4.9 vs. 2.2 in) for plots with soil pH of 4 and 6, respectively, averaged across tree species. In subsequent years, the growth rate of trees was unaffected by having acidified the soil. Over the course of five years, the average annual mortality rate for the trees was 1.4, 4.0, 9.7, and 12.2% for Canaan fir (pH 4), Canaan fir (pH 6), Fraser fir (pH 4), and Fraser fir (pH 6), respectively. However, all tree mortality for Canaan fir planted into acidified soil occurred during the first two years. A root dip with potassium phosphite at the time of planting only benefitted Fraser fir. Minimizing losses of trees in this field would require planting species less susceptible or resistant to phytophthora root rot infection and soil acidification. Index words: soil acidification, phytophthora root rot, potassium phosphite, root dip Species used in this study: Fraser fir; Abies fraseri (Pursh) Poir.; Canaan fir; Abies balsamea (L.) Mill. var. phanerolepis Fernald Chemicals used in this study: acibenzolar-S-methyl (Actigard 50WDG); clothianidin (Arena 50WDG); imidacloprid (Xytect 2F); potassium phosphite (Helena Prophyt); sulfur

Grandfather Mountain, North Carolina—A Sky Island Wonder

Grandfather Mountain, North Carolina—A Sky Island Wonder Danika Mosher I was introduced to the wonders of high-elevation mountain-top environments in the southern Appalachians while interning as a naturalist at Grandfather Mountain Stewardship Foundation (GMSF) in 2017. I knew about the geology of the area, but I was able to witness how the geology and topography influence the distribution of species by impacting local weather patterns (Clark 2001, Potter et al. 2010, Berry and Smith 2012, NC Wildlife Resources Commission 2018). The difference in climate zones from either the NC Piedmont or even Asheville meant that these mountain tops were sky islands (NC Wildlife Resources Commission 2018); and a closer look at their biological diversity confirms their uniqueness (e.g., White et al. 2012, Kaylor 2015, Ulrey et al. 2016, NC Wildlife Resources Commission 2018, USDA 2018). On a grand scale, these mountaintop islands were introduced to us interns as spruce– fir forests, being primarily composed of red spruce (Picea rubens) and Fraser fir (Abies fraseri) (Berry and Smith 2012, White et al. 2012). Other hardwoods can reside in these areas such as the North American beech (Fagus grandifolia), yellow birch (Betula alleghaniensis), mountain ash (Sorbus americana), Catawba rhododendron (Rhododendron catawbiense), and mountain maple (Acer spicatum), but can only survive at certain elevations (Newell and Peet 1996). Fraser fir dominate the peaks by thriving in shallow soils and requiring disturbances such as wind and ice, but they are endangered despite commonly being planted as Christmas trees (White et al. 2012, Cory et al. 2017). Fraser fir only exist on a few mountain tops, including Roan Mountain, Beech Mountain, Grandfather Mountain, Unaka Mountain, Whitetop Mountain, Mount Mitchell, Great Smoky Mountains, and the Great Balsams. With these populations being so far apart, they harbor other endangered, endemic, or disjunct species such as the Carolina northern flying squirrel, Blue Ridge goldenrod, Heller’s blazing star, Weller’s salamander, spruce–fir moss spider, Gray’s lily, and northern saw-whet owl (White et al. 2012, Kaylor 2015, NC Wildlife Resources Commission 2018, USDA 2018). This habitat has endured much in the past, including extensive logging at the beginning of the twentieth century (White et al. 2012, USDA 2018, NC Wildlife Resources Commission 2018) and the introduction of balsam woolly adelgid in the 1950s (White et al. 2014). Climate change poses a new threat to species as deciduous trees encroach into higher elevations, slowly replacing spruce–fir habitat and the endemic species that reside in them (Newell and Peet 1996). [End Page 283] The GMSF aims to conserve this habitat through education and providing space for visitors to respectfully explore and discover the sky island. These ideas stuck with me and led me to combine my biogeography, geology, and climatology knowledge to understand this area better and to aid the mission of conservation through my thesis research at East Tennessee State University. What happened to this habitat in the past when it was warmer than now? What about when it was cooler? How fast did red spruce and Fraser fir migrate? Where could they be heading in the future? Is that migration rate any different than before? These questions may be answered through ecological niche modeling (Aldy et al. 1999, Hijmans et al. 2006, Dietl and Flessa 2009, Koo et al. 2014, Chemura et al. 2015) and can advance conservation efforts for this unique habitat. Science helps me understand the wonders of nature and how they come to be, but it is not the only medium I use to converse ideas, start conversations, and inspire. Painting has been a lifetime passion, with landscapes being one of my favorite subjects. Both science and art require being observant, but art allows us to observe a subject in a different light. Art can also be utilized to help inform the public about conservation efforts, general science, and to incite wonder and curiosity. I have illustrated scientific processes for soil and planting trees for The Garden Club of America and created paintings for places like the Linville Peak at Grandfather Mountain with Catawba rhododendron in the foreground, rare species such as the Heller’s blazing star, and other Appalachian locations such as Watauga Lake. Grandfather Mountain is...

Phytophthora abietivora, A New Species Isolated from Diseased Christmas Trees in Connecticut, U.S.A.

A number of fir species (Abies) are produced as Christmas trees around the world. In particular, Fraser fir (Abies fraseri (Pursh) Poir.) is popular as it yields high-quality Christmas trees in temperate North America and Europe. A Phytophthora sp. causing root rot on Fraser fir was isolated from a Christmas tree farm in Connecticut, U.S.A., and found to be new to science according to morphological and molecular phylogenetic analysis using multilocus DNA sequences from ITS, Cox1, β-Tub, Nadh1, and Hsp90 loci. Thus, it was described and illustrated as Phytophthora abietivora. An informative Koch's postulates test revealed that P. abietivora was the pathogen causing root rot of Fraser fir.

Bionomics of the pine needle scale (Hemiptera: Diaspididae), an emerging pest in Christmas tree (Pinaceae) plantations in southern Québec, Canada

AbstractThe pine needle scale, Chionaspis pinifoliae (Fitch) (Hemiptera: Diaspididae), has the status of an emerging pest in Christmas tree (Pinaceae) plantations in Québec, Canada. The scale is not known to cause any significant damage yet and is not generally monitored by growers. However, it can be an obstacle for exportation to Christmas tree markets where scale insects are strictly regulated. In this study, we describe its life cycle in Christmas tree plantations in southern Québec. We confirm the presence of both parthenogenetic and sexual forms of the scale on Fraser fir Abies fraseri (Pursh) Poiret (Pinaceae) grown as Christmas trees, and of parasitoid and Coccinellidae (Coleoptera) specialists that could contribute to its control.

Shearing Systems for Fraser Fir (Abies fraseri) Christmas Trees

Plantation-grown Fraser fir (Abies fraseri (Pursh) Poir.) Christmas trees were subjected to nine shearing regimes over nine years in a plantation in western North Carolina (USA). Treatments differed in the year of onset as well as the length of the residual leader (25 to 46 cm). Long leaders (36 to 46 cm) yielded trees that were taller than trees sheared with short leaders (25 to 30 cm), but the gain in height was offset by a lower average U.S. Department of Agriculture grade. Late in the rotation, trees sheared with 36–46-cm leaders were 17–34% heavier than those with 25–30-cm leaders. Average wholesale price of trees sheared with long leaders was 57% greater than that of trees sheared with short leaders. Assuming good bud density on leaders and branches, and considering other factors as well, the optimum leader length for Fraser fir Christmas trees in western North Carolina appears to be 30 to 41 cm (12 to 16 inches). Depending on site quality and variation in bud density and vigor among individual trees, leader length can be reduced, if necessary, to increase crown density.