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Although Dutch elm disease (DED) is the primary threat to American elm (Ulmus americana L.), we hypothesized that shoot freezing injury may also limit tree productivity and survival in the north. We assessed shoot cold tolerance and field winter injury of American elm bred for DED tolerance planted in Lemington, Vermont. We tested for differences in cold tolerance associated with date, maternal DED tolerance sources, paternal sources from plant hardiness zones 5a, 6a, and 6b (determined using data from 1996 to 2005), and the interactions of these. Cold tolerance was greatest in the winter, followed by fall and then spring. For all dates, cold tolerance never differed between maternal DED tolerance sources. However, in mid-winter, paternal sources from zone 5a (coldest zone) were significantly more cold tolerant than sources from zone 6b (warmest zone), and sources from zone 6a were intermediate. Field freezing injury confirmed that shoots were only marginally cold tolerant relative to ambient temperature lows.

A Mycena species new to science was obtained from moist chamber cultures of trunk bark of a living American elm tree (Ulmus americana) located in the Fort Worth Botanic Garden, Tarrant County, Texas. This discovery was part of an ongoing study of corticolous myxomycetes on larger American elm trees occurring in Fort Worth nature parks. More than 15 American elm trees were sampled for trunk bark but only a single tree yielded Mycena basidiomes. Collections of bark began in the summer of 2017 and continued until the beginning of 2020. Bark samples from the north, south and west side of the tree yielded fruit bodies of the mushroom in moist chamber culture. No fruit bodies were observed in nature nor were early formation stages on the underside of the bark. Crystals previously described in another study were present on the bark surfaces, edges, and undersides. Habit and morphological development were photographed using light microscopy applying multifocal imaging and computer stacking to increase depth of field. Basidiome development was observed and photographed from the earliest primordial beginning stage, the button stage, intermediate stage and the final emerging stalk elongation and mature cap formation stage. Mature mushroom development took from 9 to 21 days after wetting the bark in moist chamber cultures. Scanning electron microscopy was used to illustrate development of the button stage, emerging stalk and pileus stage, and the fully mature pileus, lamellae, and pseudocollarium. Morphological features and DNA sequence data confirmed that this Mycena species was undescribed and distinct from other Mycena taxa. Morphological features suggest placement of the novel taxon in Mycena sect. Viscipelles, distinct from other members based on morphological characters and phylogenetic analysis.

The effects of Dutch elm disease (DED, Ophiostoma novi-ulmi) on 106,738 American elm (Ulmus americana L.) trees in Milwaukee WI, USA was contrasted through ecologic and economic results of an Actual Outcome to management alternatives of No Control, three sanitation intensities (Best, Good, Fair), and No DED over 40 years. No Control was like the Actual Outcome with over 99% of trees dead. The greatest loss of ecosystem values and lowest net present value (NPV) and benefit to cost ratio (B/C) occurred with the Actual ($8 to $80 million NPV, 0.8 to 1.1 B/C) and No Control ($-7 to $57 million NPV, 0.7 to 0.9 B/C) alternatives. Best Control (1.0% annual mortality) retained the highest tree population (50% survival) and ecosystem value ($161 to $175 million NPV, 1.2 to 2.5 B/C). Good Control (3.5% annual mortality) and Fair Control (5.0% annual mortality) were better alternatives than No Control or the Actual Outcome with 21% and 12% of trees respectively surviving. Not surprising, a No DED scenario retained the highest ecosystem value ($202 to $257 Million NPV, 2.0 to 3.4 BC) with 70% tree survival. The value of stormwater maintained by trees under the Best Control was like the annual cost of this alternative. All other ecosystem values (e.g., air pollution, energy conservation, carbon uptake and storage) were thus retained at no additional cost. This study provides forest pest and disease management strategies for other serious pest problems such as emerald ash borer (Agrilus planipennis) threatening urban tree populations.

The invasive alienScolytus schevyrewiSemenov (Coleoptera: Curculionidae: Scolytinae) was detected in Saskatchewan and Manitoba, Canada, in 2007. BecauseS. schevyrewiis a potential vector of the Dutch elm disease pathogen (Ophiostomanovo-ulmiBrasier; Fungi: Ophiostomataceae), the natural history of the beetle was studied from 2009 to 2012 in the two provinces, where the disease is managed to protectUlmus americanaLinnaeus (Ulmaceae). Typically, healthy trees become infected when their xylem is contacted during feeding by spore-bearing scolytine adults that have flown from a diseased tree; adults emerging from brood galleries in diseased trees frequently carry spores. We caught flyingS. schevyrewiadults from May to October; adults were weakly attracted to healthyUlmusLinnaeus but were strongly attracted toUlmus pumilaLinnaeus stressed by girdling.Scolytus schevrewicolonised and completed development in girdled trees and trap logs ofU. pumila. In contrast to other studies,U. americana– the major source of pathogen spores in the area – was never colonised as a brood host. Our results suggest thatS. schevyrewiwill primarily useU. pumila, which, in Manitoba and Saskatchewan, seldom exhibits symptoms of Dutch elm disease. Thus, arrival ofS. schevyrewidoes not appear to require changes to Dutch elm disease management programmes.

Fungicide injection is regularly performed to prevent and manage Dutch elm disease (DED) of American elm (Ulmus americana). In an effort to better understand the effects of long-term fungicide injection on tree health, sonic tomography (SoT) and electrical-resistance tomography (ERT) were used to nondestructively determine the incidence and severity of internal decay in the lower trunk of American elms in suburban and urban settings. Overall, 253 sonic and electrical-resistance tomograms were generated from 210 American elms. Sampled trees were partitioned into two fungicide injection groups: (1) regular injection; and (2) irregular injection or no known history of injection. Among all American elms, the incidence of internal decay in the lower trunk was 30% (63/210) with a mean percent decay, as determined by SoT, of 39%. Based on Chi-square analysis, there were no significant differences in the frequency of elms with decay by injection history (P = 0.799). Mean percent decay was significantly different by dbh class (P = 0.005) and while linear regression demonstrated a positive correlation between percent decay and dbh, most of the variability went unexplained (R2 = 0.182). For elms with decay, there was a significantly higher frequency of trees in the lowest decay class (< 25% of the cross section) compared to the highest decay class (> 75% of the cross section). The results suggest that the wounding associated with regular fungicide injection does not increase the likelihood of internal decay and that American elms exhibit a low frequency and severity of internal decay.

The apple tree is affected by a large variety of phytophagous plants. Woolly apple aphid in apple trees, Eriosoma lanigerum (Hausmann) (Hemiptera: Aphididae) are from North America. The main host of this insect is the plant Ulmus americana L. and the secondary host is the apple tree, where it develops throughout the year. Collects were carried out in pioneer municipalities in the planting of apple trees in the state of Espirito Santo, being cultivated Eva, Gala and Fuji varieties. The collections took place in the municipality of Santa Teresa, Santa Maria de Jetiba and Mantenopolis. Samples were taken at the stages of vegetative development and apple production. In this study, the occurrence of this insect was recorded in apple orchards in the state of Espirito Santo, where the presence of E. lanigerum was observed in all the samples, attacking the trunk, new shoots, roots, shoots and fruits between the planting lines.

A Licea species new to science is described on the bark surface of living American elm (Ulmus americana L.) cultured in moist chambers. It is characterized by an iridescent peridium on the sides of the sporangium, a black apical circular patch of globular debris, and dark reddish black spores that are smooth over half the surface and ridged-reticulate over the other half with the paler thinner wall collapsing into a coffee-bean shape. This combination of morphological characters is distinct and separates this taxon from all other species of Licea. The history of moist chamber culture use and field collection of corticolous myxomycetes is reviewed. The discovery of crystals of unknown origin on the bark surface of American elms associated with Licea species are illustrated with light microscope photography and scanning electron microscopy. Light microscope images and habit photographs were made using multi-focus imaging and computer stacking to increase depth of field and provide illustrations in color of sporangial structures of the new Licea species. This tiny short-stalked Licea approximately 100 um in height, and with distinctive external and internal morphological characters, was photographed using scanning electron microscopy. Dark-spored versus light-spored species of Licea are reviewed and compared with the most recent molecular analysis as this relates to the genus Licea. This paper is the first in a series that will document the discovery of Licea fruiting bodies of four new species on American elms in nature parks near Fort Worth, Texas.

American elm,Ulmus americanaL., was cultivated widely in USA and Canada as a landscape tree, but the genome of this important species is poorly characterized. For the first time, we describe the sequencing and assembly of the chloroplast genomes of two American elm genotypes (RV16 and Am57845). The complete chloroplast genome ofU. americanaranged from 158,935-158,993 bp. The genome contains 127 genes, including 85 protein-coding genes, 34 tRNA genes and 8 rRNA genes. Between the two American elm chloroplasts we sequenced, we identified 240 sequence variants (SNPs and indels). To evaluate the phylogeny of American elm, we compared the chloroplast genomes of two American elms along with seven Asian elm species and twelve other chloroplast genomes available through the NCBI database. As expected,Ulmuswas closely related toMorusandCannabis, as all three genera are assigned to the Urticales. Comparison of American elm with Asian elms revealed thattrnH was absent from the chloroplast of American elm but not most Asian elms; conversely,petB,petD,psbL,trnK, andrps16 are present in the American elm but absent from all Asian elms. The complete chloroplast genome ofU. americanawill provide useful genetic resources for characterizing the genetic diversity ofU. americanaand potentially help to conserve natural populations of American elm.

Evening Grosbeak (Coccothraustes vespertinus) populations have been hypothesized to be in steep decline across North America. Data characterizing long-term changes are needed to quantify the magnitude of the declines. We surveyed grosbeaks at a spring migratory stop-over site in Corvallis, Oregon, USA, where birds gather annually during April and May to feast on elm (Ulmus spp.) seeds before departing to breeding sites. An estimate produced by a statistics professor in the 1970s indicated peak numbers were 150,000 to 250,000 birds. Our surveys in 2013–2015 found annually variable numbers, from a few hundred grosbeaks in the lowest year to less than five thousand birds in the highest year. If the original estimate is approximately true, Evening Grosbeak numbers have experienced dramatic declines, averaging −2.6%/year, over the last four decades. Our local observation of declines during spring aligns with declines documented in winter across North America by bird feeder studies and in summer by the Breeding Bird Survey. We explore potential explanations for the changes in population size, such as influences of spruce budworm outbreaks, disease, and decreased structural diversity of forests owing to harvest practices. We also consider the challenges of interpreting changes in abundance of species with exceptionally variable populations, especially if population fluctuations or cycles may have long periodicities. Finally, we call for additional planned surveys to track the numbers of this enigmatic and charismatic species.

Past research has shown that plants possess the capacity to alter their instantaneous response of photosynthesis to temperature in response to a longer-term change in temperature (i.e. acclimate). This acclimation is typically the result of processes that influence net photosynthesis (Anet), including leaf biochemical processes such as the maximum rate of Rubisco carboxylation (Vcmax) and the maximum rate of photosynthetic electron transport (Jmax), stomatal conductance (gs) and dark respiration (Rd). However, these processes are rarely examined in the field or in concert with other environmental factors, such as precipitation amount. Here, we use a fully factorial warming (active heating up to +4 °C; mean = +3.1 °C) by precipitation (−50 % ambient to 150 % ambient) manipulation experiment in an old-field ecosystem in the north-eastern USA to examine the degree to which Ulmus americana saplings acclimate through biochemical and stomatal adjustments. We found that rates of Anet at ambient CO2 levels of 400 µmol mol−1 (A400) did not differ across climate treatments or with leaf temperatures from 20 to 30 °C. Canopy temperatures rarely reached above 30 °C in any treatment, suggesting that seasonal carbon assimilation was relatively homeostatic across all treatments. Assessments of the component processes of A400 revealed that decreases in gs with leaf temperature from 20 to 30 °C were balanced by increases in Vcmax, resulting in stable A400 rates despite concurrent increases in Rd. Photosynthesis was not affected by precipitation treatments, likely because the relatively dry year led to small treatment effects on soil moisture. As temperature acclimation is likely to come at a cost to the plant via resource reallocation, it may not benefit plants to acclimate to warming in cases where warming would not otherwise reduce assimilation. These results suggest that photosynthetic temperature acclimation to future warming will be context-specific and that it is important to consider assimilatory benefit when assessing acclimation responses.

The EFSA Panel on Plant Health (PLHP) performed a pest categorisation of Saperda tridentata (Coleoptera: Cerambycidae) for the EU. S. tridentata (elm borer) occurs in eastern North America. Ulmus americana and U. rubra are almost exclusively reported as hosts, apart from two 19th century records from the USA of larvae from Acer sp. and Populus sp. The Panel does not exclude the possibility of a post-entry shift in host range to European Ulmus or Acer and Populus. S. tridentata infests trees that are already weakened, and severe infestations can result in tree death. S. tridentata occurs across a range of climate types in North America that occur also in Europe. Between 2016 and 2019, S. tridentata larvae were intercepted with North American Ulmus logs imported into the EU. In the EU, American Ulmus species are mainly found in arboreta and as ornamental specimen trees. If only North American Ulmus are hosts, establishment is unlikely. However, if European Ulmus, Populus or Acer species become hosts, establishment is much more likely, with impact confined to already weakened trees. The information currently available on geographical distribution, biology, impact and potential entry pathways of S. tridentata has been evaluated against the criteria for it to qualify as potential Union quarantine pest or as Union regulated non-quarantine pest (RNQP). Since the pest is not reported in EU, it does not meet the criteria assessed by EFSA to qualify as potential Union RNQP. S. tridentata satisfies the criterion for quarantine pest regarding entry into the EU territory. Due to the scarcity of data, the Panel is unable to conclude if S. tridentata meets the post-entry criteria of establishment, spread and potential impact.

Ulmus americana (American elm) was an important urban tree in North America prior to the introduction of the Dutch elm disease (Ophiostoma ulmi and O. novo-ulmi) pathogen in 1930. Subsequently, urban and community forests were devastated by the loss of the large canopies. Disease tolerant elms (Ulmus spp.) of various species were later developed; however, consumer acceptance of these trees was slow. The goal of the National Elm Trial was to evaluate newer cultivars of elm across the United States. Trees were monitored for survival and growth for 7 to 10 years at 16 different locations. 'Morton' elm had >90% survival, while 13 cultivars averaged 70 to 90%, and five cultivars ranged from 25 to 69% survival. Trunk diameter growth by location ranged from 0.5 cm year-1 at Colorado to more than 2.0 cm year-1 at Iowa. By taxa, trunk diameter growth ranged from a low of 'JFS Bieberich' elm (0.7 cm year-1) to a high of 'New Horizon' elm (1.7 cm year-1). The fastest height growth was found with the American elm cultivars 'New Harmony' and 'Princeton' (0.63 and 0.61 m year-1, respectively).

The objective of this project was to validate the efficacy of a miniature multispectral, single-sensor camera for detecting stress in deciduous juvenile tree foliage in a controlled environment. To that end, deciduous liners (one year old, nursery-grown transplants) representing five tree species (Celtis occidentalis L., Gleditsia triacanthos forma inermis Schneid, Gymnocladus dioicus (L.) K. Koch, Quercus rubra L., and Ulmus americana L.) were containerized and subsequently subjected to two treatments representing common landscape site stresses: drought and elevated soil pH. To minimize any atmospheric effects on reflectance values, the trees were placed in enclosed, artificially lit chambers during the detection process. The normalized difference vegetation index (NDVI) was utilized as the metric for analysis. Results showed the single imager sensor derived NDVI values were reliable indicators of tree stress within the species groups. Results also revealed that the derived values were not reliable indicators of tree stress across the species groups.

Ideally, variants of single-tree, group, and patch selection create new, spatially aggregated age classes and maintain a diversity of tree species and sizes in multiaged, mixed-species forests. We explored this notion in northern hardwood forests on the Menominee Nation, a forest ecosystem without the exploitive cutting history of most forests in the western Great Lakes region. Although the outcomes suggested a lack of relationship between gap characteristics and tree density, the expectations for tree regeneration were largely met: gap tree densities were >600 stems/ac and predominantly composed of sugar maple (Acer saccharum), American elm (Ulmus americana), and yellow birch (Betula alleghaniensis). Examination of stand diameter distributions indicate that gaps may not be necessary to establish regeneration on Menominee forests. To deepen the interpretation of our results, we include field and office discussions regarding the practicality of group openings when managing this forest.

A rapid and accurate method to detect the common strain of elm yellows (EY) phytoplasma in elm and insect samples was developed using a real-time polymerase chain reaction (PCR) procedure based on the TaqMan minor-groove-binder probe. Primers and probe were designed based on the EY phytoplasma-specific translocation protein secY gene DNA sequence. Success of the DNA extraction procedure was evaluated by amplifying the chloroplast trnL gene of Ulmus americana. The real-time PCR assay reacted positively with EY and EY phytoplasma strain ULW DNA, an isolate which occurs in Europe. It did not cross-react with Illinois EY or aster yellows phytoplasma DNA, both of which are known to occur in elm trees in the United States, nor did it amplify several other phytoplasmas belonging to the 16SrV and other phylogenetic groups. The real-time PCR protocol was used to identify 30 EY-positive elm trees on The Pennsylvania State University, University Park campus. Threshold cycle (CT) values obtained from the EY phytoplasma-infected elm trees ranged from 15 to 37. EY phytoplasma was detected in several leafhopper taxa. This real-time PCR method can be used for the diagnostic screening of elm trees and for the identification of possible insect vectors of EY phytoplasma.

A survey of urban trees affected by bacterial leaf scorch (BLS) caused by Xylella fastidiosa was conducted in the District of Columbia during 2011 and 2012. Over 20 species of urban trees were evaluated at 95 sites. Symptomatic and asymptomatic foliage from trees with BLS symptoms and foliage from neighboring asymptomatic trees were sampled. An X. fastidiosa-specific enzyme-linked immunosorbent assay (ELISA) and a polymerase chain reaction assay were used to detect and identify the strains from environmental samples. Symptomatic trees testing ELISA-positive for X. fastidiosa occurred most frequently with Quercus palustris, Q. rubra, Ulmus americana, and Platanus occidentalis. The bacterium was also less frequently identified on eight other symptomatic and five asymptomatic tree species. On infected trees, the bacterium was also detected on the asymptomatic portion of seven tree species. All strains were identified as the X. fastidiosa subsp. multiplex genotype ALSII except on Morus alba, where the genotype ALSI and the subsp. sandyi were detected. The occurrence of crown dieback was found significantly associated with X. fastidiosa-infection on Q. palustris, Q. rubra, U. americana, and P. occidentalis. Because this pathogen continues to perpetuate uncontrolled in urban environments, there is a pressing need to identify long-term management strategies that abate disease.

The Wabash and Erie Canal system was an important transportation network in the early 1800s prior to the dominance of trains and later automotive transportation. In this work, timbers from Culvert 151 were examined, after they were exhumed during construction of Hwy 641 on the south side of Terre Haute, Indiana. Cross-sections were taken from each of 22 beams and allowed to air dry to determine the stability of the timbers. We examined the wood to determine the genera or species of each sample that was used in this construction project and developed a floating chronology from our white oak group samples. The mix of species present included 11 beams of American beech (Fagus grandifolia), five white oak group (Quercus subgenus Lepidobalanus), and one each of American elm (Ulmus americana), winged elm (Ulmus alata), sugar maple (Acer saccharum), shagbark hickory (Carya ovata), white ash (Fraxinus americana), and black walnut (Juglans nigra). This suggests that the timbers were cut from the available...

Popular trees that are known to grow well in a region are often the first ones people choose to plant in the landscapes that surround them. Historically, this has resulted in over-planting particular species, such as the American elm (Ulmus americana). This species had little genetic variation in its natural resistance to Dutch elm disease (Ophiostoma ulmi), leading to the death of most American elms. In many areas, the species of trees that are well suited to urban conditions are somewhat limited; those suitable as street trees are even more limited. Analyses of urban tree inventories worldwide show the problem of overplanting still exists in many cities, with the average abundance of the most common species being about 20% worldwide, while being over 40% in some cities. The current ability to clone trees with desirable characteristics means that many tree species planted today have even less genetic variation than those planted from seeds in previous decades. Climate change will bring new growing challenges for urban trees. Trees that grew well under environmental conditions of the past may no longer be suitable in the future. Coupling these factors places cities in danger of rapidly losing large numbers of urban trees, with grave environmental and human consequences, including increased urban heat island temperatures and more heat-related human deaths.

The American elm (Ulmus americana) is a highly desirable deciduous shade tree with moderately dense foliage and a symmetrical broad or upright vase-shaped crown. This plant is susceptible to various diseases because of rapid terminal growth when new springwood vessels are fully functional. The American elm, along with many other shade tree species, can be affected by Xylella fastidiosa (Hearon et al. 1980), and X. fastidiosa has been previously confirmed on American elm in Ontario (Goodwin and Zhang 1997), Washington, D.C. (Harris and Balci 2015), Oklahoma (Olson et al. 2006), and Alabama (Parker et al. 2012). X. fastidiosa colonizes the xylem vessels of plant hosts and can cause bacterial leaf scorch disease (Pearson et al. 1998). On elm, X. fastidiosa causes leaf discoloration and browning, marginal scorching, and dieback. In the summer of 2019, chlorosis and marginal leaf scorch symptoms consistent with those of bacterial leaf scorch disease were observed on an American elm tree in a nursery in Pulaski County, Georgia. This elm tree was propagated from cuttings taken from a mature tree in Houston County, Georgia. Initial identification of the disease was performed by assessing characteristic symptoms of infection like leaf scorch, dieback signs, and so on, as described in Hernandez-Martinez et al. (2006). X. fastidiosa was verified via molecular and serological methods. Genomic DNA was extracted from the petioles and midribs of symptomatic leaves using the DNeasy Plant Kit (Qiagen, Valencia, CA), and real-time PCR was performed in a Cepheid smart cycler II (Sunnyvale, CA) using iQ SYBR Green Supermix (BioRad Laboratories, Hercules, CA). A 25-µl reaction was prepared according to the manufacturer’s protocol with primers XF-F/XF-R, which target the 16s rRNA processing protein (Harper et al. 2010). Real-time PCR results confirmed the presence of X. fastidiosa in all symptomatic leaves. The recombinase-polymerase-amplification technology-based AmplifyRP Acceler8 end-point detection assay (Agdia, Elkhart, IN) was carried out on symptomatic tissue using according to the manufacturer’s instructions, and this assay also confirmed the presence of X. fastidiosa in all symptomatic leaves (Waliullah et al. 2019). For further confirmation, the remaining petiole tissue was tested for X. fastidiosa using the DAS-ELISA Reagent Set for X. fastidiosa (Agdia) with minor modifications to the manufacturer’s protocol. In addition to tests of the symptomatic plant, testing of leaves from five additional young elm trees from the same nursery was also carried out according to the same procedures. These five visually healthy young elms tested negative for X. fastidiosa based upon all three testing methods. In total, three independent tests confirmed the presence of X. fastidiosa in symptomatic elm tissues, whereas asymptomatic elm trees from the same nursery tested negative. Attempts to isolate the bacteria from symptomatic leaf tissue on periwinkle wilt media (Davis et al. 1981) were not successful; however, the strong association of symptoms with the thrice-confirmed presence of X. fastidiosa in symptomatic tissue clearly indicates the role of X. fastidiosa in the observed symptoms. Although X. fastidiosa is most commonly transmitted by xylem-feeding insects, cuttings taken from infected hosts can produce infected plants; however, the mature tree used for propagation in this case could not be located for testing. To the best of our knowledge, this is the first report of X. fastidiosa associated with the American elm in Georgia. The presence of X. fastidiosa in American elm has the potential to impact homeowners, landscapers, and nursery producers within Georgia, and our findings suggest that Georgia tree nursery growers should monitor their nursery stock for bacterial leaf scorch disease.

This study has applied an integrated airborne laser scanning (ALS) and geographic information systems (GIS) technique to estimate urban tree damages caused by an ice storm that affected the City of Norman, Oklahoma between 8 and 11th of December, 2007. Pre- and post-storm ALS data were collected and processed using GIS. The pre-storm ALS data was used to create a digital elevation model (DEM) and the pre-storm digital surface model (DSM) while the post-storm DSM was created from post-storm ALS data. The DEM were subtracted from the two DSMs to create the pre- and post-storm canopy height models (CHMs). Individual and grouped trees were then separated using a combination of Koukoulas and Blackburn and local maxima tree extraction algorithms. Finally, differences in height and canopy diameter between the pre- and post-storm CHMs within the extracted trees were calculated to measure the damage. Results showed that approximately 9% of the urban trees were completely damaged while almost 6% did not sustain any damage. It also showed that tree damage from ice storms varied with species and that Acer saccarinum, Acer saccharum Marsh, Ulmus americana , and Ulmus pumila were most vulnerable while Platanus occidentalis and Quercus palustris were the most resilient tree species to the ice storm. When compared with the ground reference data, it was found that the proposed methodology can detect tree height/stem damage with >81% accuracy compared to >42% accuracy in canopy damage assessment. Once ALS data is collected after a disaster, the methodology can provide a quick estimate of urban tree damage and hence be useful for city planners. It can also be used to create detailed inventories of tree heights of urban forests and monitor their growth and changes to improve their long-term sustainability.

Ulmus americana (American elm) was an important urban tree in North America prior to the introduction of the Dutch elm disease pathogen in 1930. Subsequently, urban and community forests were devastated by the loss of large canopies. Tree improvement programs produced disease tolerant American and Eurasian elm cultivars and introduced them into the nursery industry. However, consumer acceptance was slow. The National Elm Trial was established to evaluate commercially available taxa of elm across the United States. Established at 16 locations, these plantings monitored survival and growth, as well as disease and insect pressure for 7 to 10 years. ‘Morton’ elm had >90% survival, while 13 cultivars averaged 70% to 90%, and five cultivars ranged from 25% to 69% survival. Trunk diameter growth by location ranged from 0.5 cm/year (Colorado, U.S.) to more than 2.0 cm/year (Iowa, U.S.). By taxa, trunk diameter growth ranged from a low, by ‘JFS Bieberich’ elm (0.7 cm/year), to a high by ‘New Horizon’ elm (1.7 cm/year). Scale insects were minor issues at most trial locations, except Colorado, where scales contributed to the death of several cultivars. Performance ratings (scale 1 to 5) ranged from 2.7 for ‘JFS Bieberich’ elm to 4.5 for ‘New Horizon’ elm. Based on the ratings, the preferred cultivars of American elm were ‘New Harmony’ and ‘Princeton’, and the preferred cultivars of Asian elm were The Morton Arboretum introductions and ‘New Horizon’. These findings will help green-industry professionals determine what elm cultivars will perform the best in different regions.

This study describes a protocol for regeneration of plants from cell suspension-derived protoplasts of American elm (Ulmus americana). Efficient protoplast isolation was achieved from a two-phase culture system through the incorporation of 100 μM 2-aminoindan-2-phosphonic acid, with a yield of approximately 2 × 10(6) protoplasts/ml packed cell volume. Isolated protoplasts failed to survive in liquid or alginate bead culture systems but initiated and continued to divide when embedded in low melting point agarose beads. Protoplast-derived callus proliferated and differentiated into shoot buds in response to 10 or 20 μM thidiazuron. Differentiated buds elongated and continued to proliferate on elm shoot medium supplemented with 3.0 μM GA3. The protoplast-derived shoots rooted and acclimatized to greenhouse conditions and continued to grow. This system provides the first protoplast-to-plant regeneration system for American elm and provides a framework for the development of protoplast fusion or genome editing technologies.

Emergence patterns and sex ratios of the twig girdler, Oncideres cingulata (Say), were examined during 2004–2005 relative to measures of twig morphology and species of host tree. Emergence patterns varied significantly between study years, by sex, and among host species. Beetles emerged an average of 10 days earlier in 2004 than in 2005. Mean date of emergence for male beetles was 3 days earlier than for females. Beetles emerged from twigs girdled from honey locust (Gleditisia triacanthos L.) a day earlier than from American elm (Ulmus americana L.), 2 days earlier than from pecan (Carya illinoensis (Wangenh.) K. Koch), and 4 days earlier than from birch (Betula nigra L.). However, regression models found only weak relationships between twig morphology parameters and the timing of emergence of beetle adults. Similarly, sex ratios were unrelated to any aspect of twig morphology and did not vary between years or among host species.

Summary Dutch Elm Disease (DED) is a vascular wilt disease of Ulmus species (elms) incited in North America primarily by the exotic fungus Ophiostoma novo-ulmi. The pathogen is transmitted via root grafts and elm bark beetle vectors, including the native North American elm bark beetle, Hylurgopinus rufipes and the exotic smaller European elm bark beetle, Scolytus multistriatus. The banded elm bark beetle, Scolytus schevyrewi, is an exotic Asian bark beetle that is now apparently the dominant elm bark beetle in the Rocky Mountain region of the USA. It is not known if S. schevyrewi will have an equivalent vector competence or if management recommendations need to be updated. Thus the study objectives were to: (i) determine the type and size of wounds made by adult S. schevyrewi on branches of Ulmus americana and (ii) determine if adult S. schevyrewi can transfer the pathogen to American elms during maturation feeding. To determine the DED vectoring capability of S. schevyrewi, newly emerged adults were infested with spores of Ophiostoma novo-ulmi and then placed with either in-vivo or in-vitro branches of American elm trees. The inoculation of trees via feeding wounds was successful 30% of the time for in-vivo trials and 33% for in-vitro trials. Although the infection rate of DED has declined in Colorado over the past 10 years, the disease is still present in urban elms. While it appears that S. schevyrewi is another vector of the DED pathogens, it appears that S. schevyrewi is no more efficient than S. multistriatus. Thus, management programs that remove elm bark beetle breeding sites, rapidly remove DED-infected elms and include the planting of DED-resistant elms should continue to be effective management tactics.

Available habitat for the endangered Indiana bat (Myotis sodalis) varies widely across the species’ broad range and the species’ degree of habitat use specificity is not known; therefore, it is necessary to characterize the species’ habitat use patterns regionally to provide suitable guidelines for wildlife managers to conserve the species throughout its range. Understanding day roost characteristics is particularly important because habitat suitability for Indiana bats is thought to be based on the availability of suitable day roost structures. Despite having been extensively studied at the core of their range, few studies of Indiana bat day roost characteristics have been published from the northeast periphery of the species’ range, and no studies have been published from central New York State, where populations have been in steep decline due to White-Nose Syndrome since 2006. I studied day roosts of 20 female and 7 male Indiana bats in the Ontario Lake Plain northwest of Syracuse, New York, USA during the spring of 2006 and summers of 2007 and 2008 and identified 96 individual Indiana bat roost trees. Indiana bats roosted in 10 species of trees, of which Carya ovata, Acer spp., and Ulmus americana were most frequent. The mean diameter of roost trees was 41.55 ± 7.53 cm, which was similar to roost trees in other regions, but larger than the mean diameter of available trees in the same stands used by roosting Indiana bats. Male and female bats used similarly sized trees. I conclude that size of roost trees in central New York are similar to those throughout the Indiana bat’s range, that the most frequently selected tree species differ regionally, and that patterns of male versus female roost selection varies regionally. This study provides regionally specific quantitative and qualitative metrics by which managers can identify potential Indiana bat habitat for land use planning and conservation.