Ulmus Research Articles

Elm zigzag sawfly, Aproceros leucopoda (Hymenoptera: Argidae), recorded for the first time in North America through community science

Abstract The elm zigzag sawfly, Aproceros leucopoda Takeuchi (Hymenoptera: Argidae), was reported for the first time in North America during the summer of 2020. Characteristic zigzag defoliation was reported in the province of Québec, Canada, on the community science website, iNaturalist. Field trips conducted to the site resulted in the collection of live specimens (a few larvae and a cocoon from which an adult emerged) and onsite observation of diagnostic defoliation and empty cocoons, confirming the presence of this exotic species in Canada. Subsequent inspection of elm trees by naturalists and scientists in the south of the province led to the conclusion that the species is more widely distributed than first expected and that the invasion is not localised to a small area. Preliminary genetic data pointed to a possible European origin of the Canadian population, but conclusive assignment to source will require examination of more specimens and the collection of reference sequences from different European and Asian populations. This is a good example of the importance of community science in the detection of new invasive species.

Qualitative and Quantitative Indicators of Foliar Mass of Woody Plants in Urban Greenspaces According to the Level of Air Pollution

The purpose of this study is to conduct a comparative analysis of the leaf fall timing and parameters of fluctuating leaf asymmetry among two commonly used plant species for street landscaping in Detroit city, namely, American elm and American ash. The study was completed between summer and fall for the year 2019 in and around Detroit, US. Phenological leaf fall timing of elm and ash was studied, and the fluctuating asymmetry index of their leaves was estimated within the city limits (80 trees of ash and 40 of elm) and outside the city (control site, 20 trees of each species). Leaf fall in city ash trees was recorded from November 1st to 4th and 5-8 days prior to the leaf fall in elms (p ≤ 0.01). Elm trees in the control group shed their leaves 10 days later compared to the city trees, i.e., on average, on November 25th (p ≤ 0.01). Ash trees in the control group shed their leaves earlier than the elm control group, on November 11th (p ≤ 0.001). In the city streets, the average fluctuating asymmetry ranged from 0.065 to 0.086 (point 1), from 0.049 to 0.078 (point 2) and from 0.063 to 0.082 (control site, near the highway).

Host plant range of Aproceros leucopoda is limited within Ulmaceae

Although much research has been carried out to develop taxa resistant to Dutch elm disease (DED), newly occurring pests represent a new challenge for the protection of elms (Ulmacae). The invasive zigzag elm sawfly (Aproceros leucopoda) is a recent invader of Asian origin in Europe defoliating elm trees that are otherwise often characterized with major resistance to DED. The range expansion of this pest poses a major threat to elms. The aim of this study was to identify the susceptibility of Ulmus crassifolia, Hemiptelea davidii and Zelkova serrata to this pest by using three different methods (oviposition trials with cut shoots and with plants in pots, and larval feeding trials with plants in pots) to define the performance of A. leucopoda on potential hosts. The fact is that A. leucopoda was unable to complete its development on either of these three taxa of Ulmaceae, whereas Ulmus pumila (the reference during the trials) was again confirmed as a true host of the pest clearly indicating that the host plant range of A. leucopoda is probably limited not only to Ulmus but also within this genus. Our results may be considered in future resistance breeding programmes, pest risk assessments, and for the selection of Ulmaceae species.

Morphology of the last instar larva and pupa of Synanthedon caucasica (Gorbunov, 1986) (Lepidoptera: Sesiidae), a serious pest of oriental plane and elm trees.

This work presents the first description of the morphology of the last larval instar and pupa of the clearwing moth species Synanthedon caucasica (Gorbunov, 1986). All diagnostic morphological characters are described in detail, compared with the closely related species Synanthedon loranthi (Králíček, 1966), and these diagnostic characters are illustrated with photographs and line drawings.

The extensive damage to elms by Dutch elm disease agents and their hybrids in northwestern Russia

Elms are important amenity trees in the European part of Russia, incl. the St. Petersburg and Leningrad Region. The native species Ulmus glabra and U. laevis mainly grow there, on the northern border of their natural range. Hybrid elm cultivars have been planted since the early 2000s. Thousands of elms suffer from Dutch elm disease in the Leningrad Region. We found that in the north-western part of Russia Ophiostoma novo-ulmi subsp. novo-ulmi and O. novo-ulmi subsp. americana as well as hybrids of these subspecies are aggressive agents of DED on elms. According to in vitro experiments of hybrids in pure cultures, O. novo-ulmi subsp. americana x novo-ulmi had the highest growth rate, and O. novo-ulmi subsp. novo-ulmi the lowest growth rate.Ulmus glabra (>40 years old) was affected the most, with ca. 20 % of assessed trees found to already be dead and only 56 % found to be in good condition. The documented health among young elm cultivars (<25 years old) revealed that only 4% were dead, and 91 % were healthy or only experiencing some branch loss. Ulmus laevis (with 74 % of individuals healthy or with some branch loss, and 5% dead) was significantly healthier compared to U. glabra. In the city, the health of all assessed elm species was significantly better in greenspaces than next to highways.As the potential vectors of DED, Scolytus scolytus, S. multistriatus and S. pygmaeus are registered in the assessed region.

Hardy’s Trees

Maxwell Sater, “Hardy's Trees: Ecology and the Question of Knowledge in The Woodlanders” (pp. 92–115) This essay attends to one of the stranger episodes in Thomas Hardy’s fiction: the inexplicably linked deaths of John South and the elm tree outside his house. I argue that this subplot is of central importance to The Woodlanders (1887) and to Hardy’s ecological thinking more generally. Hardy posits an episode that resists narrative accommodation: simply, it does not make sense. Its senselessness, I contend, indexes a broader discomfort with, and rejection of, what Stanley Cavell would call relations of knowing as the foundation of ecology. By reading The Woodlanders alongside Cavell, I suggest that Hardy develops an ecological mode of relation dependent neither on knowledge of nor on continuity with nonhuman worlds but, rather, on a negotiation of the epistemological and ontological limits inhering between, in this instance, humans and trees. For Hardy, humane ecological relations are possible in spite of those limits; in fact, seeking to transcend them, as the elm tree plot parodically demonstrates, can be counterproductive.

Dissecting Taxonomic Variants within Ulmus spp. Complex in Natural Forests with the Aid of Microsatellite and Morphometric Markers

Spontaneous hybrids between the native elms (genus Ulmus L.) have been observed in the forests of Europe. Gene conservation raises questions regarding the genetic background for the complex morphology and taxonomy of elms. Our objective was to dissect morphological and genetic variation in the natural swamps of Ulmus species groups in Lithuanian forests with the aid of leaf morphology and microsatellite (SSR) markers. We sampled leaves from 189 elms at 26 locations to grasp the phenotypic diversity in variable natural habitats in Lithuanian forests. We assigned the elms into six taxonomic and genetics groups based on 31 leaf morphology parameters and tested the genetic differentiation between these six groups at six nuclear SSR loci by using Bayesian and genetic distance-based clustering. The genetic and leaf morphometric analyses of putative elm hybrid swamps indicated a low genetic exchange between U. laevis Pall. and the other Ulmus groups. The genetic and morphometric data supported the differentiation of U. glabra Huds. and U. glabra (female) × U. minor Mill. (male) spontaneous hybrids. In addition, the results of the genetic analysis also confirmed the high level of genome sharing among U. minor and U. minor subsp. minor Richens., where leaf morphology failed to differentiate genetically discrete groups. For gene conservation, we would suggest considering separate gene conservation units selected based on leaf and stem morphology for U. laevis, U. glabra, U. glabra × minor, and the U. minor species complex.

Science art as an impetus for the development of high-tech cities

Science Art over the past 20 years has become one of the most relevant and rapidly developing forms of contemporary art, it reveals the possibilities of innovative interdisciplinary projects in which an artist and designers work in collaboration with scientists, engineers and technologists, expanding the boundaries of the concept of “art”, on the one hand, and revealing the humanistic potential of the latest achievements of science, on the other.These processes also affect the urban environment. High-tech urban clusters, accumulating significant scientific potential, through the opening of science art laboratories, in which collaborative projects of researchers and artists are carried out, stimulate the clusters development, using the intuitive principles of art. This article analyzes the examples of a successfully functioning Ljudmila laboratory in Ljubljana, the International Synthetic Aesthetics project, the My Neighborhood social networking project, and describes the case of the restoration of a historic elm tree in Biscarrosse, France. According to the results of the study, the authors conclude that cooperation between scientists and people of creative professions can turn out to be a significant vector for the development of not only science and art, but also social life in the cities where the practice of Science Art is used.

On Some Significant Phytoplasma Diseases of Forest Trees: An Update

This paper provides an updating of information of a selected number of major phytoplasma diseases of forest trees, with a focus on the associated phytoplasma taxa. Phytoplasma diseases of forest trees have been less extensively studied than those affecting fruit trees. Research on the role of phytoplasmas as the cause of diseases of forest trees has only in the last few years been intensified, after sensitive and specific detection methods greatly based on PCR technology became available. Various phytoplasma taxa have been identified in naturally infected elm, ash, conifer, sandal, and eucalyptus trees, whereas only one phytoplasma taxon has been recorded in naturally infected alder trees. However, for almost all of the reviewed diseases, there is still sparse information about insect vectors, plant host range, strain virulence, pathogenicity, and host tolerance and resistance. Knowledge of these aspects is the basis for appropriate disease management. In particular, further research is required to clarify the role of phytoplasmas in asymptomatic trees. In addition, the etiological role of various “non-specific” phytoplasma taxa, which have been recorded in forest trees, while no data from pathological studies are available, needs to be further investigated.

Особенности состояния ильмовых в защитных насаждениях засушливой зоны Нижнего Поволжья

In the Volgograd region, which belongs to low-forest regions, old-growth plantings pre-dominate, in which about 80,0% of the total dendrological composition is accounted for by repre-sentatives of the generic Ulmus complex. In the conditions of urbanization, the pathological pro-cesses and the weakening of woody plants increases. The stable weakened state of the elm trees is typical for squares and roadside plantings (Bsr = 3.28-3.36, respectively). Favorable conditions for maintaining the life optimum of elms are formed in parks, protective forest strips and arbore-tums, where healthy or weakened trees predominate (Bsr = 1,82-1,69-1,87 respectively). Phyl-lophages of different ecological groups are trophically related to the arboreal species of Ulmus. Among leaf-eating pests, Xanthogaleruca luteola Mull is of important economic importance. The pest population varies depending on the ecological conditions of the biotopes and Ulmus species. Keywords: ULMUS, PROTECTIVE FOREST STANDS, CONDITION CATEGORY, MONITORING, ANTHROPOGENIC PRESSURE, PESTS, PEST POPULATION

Pretreatment of lignocellulosic waste as a precursor for synthesis of high porous activated carbon and its application for Pb (II) and Cr (VI) adsorption from aqueous solutions

Effects of Elm tree sawdust pretreatments using alkali and alkaline earth metals (NaCl, KCl, CaCl2, MgCl2 and Elm tree ash) and deashing solutions (water, HCl, HNO3 and aqua regia) before the carbonization process on the porosity of produced activated carbons and Pb (II) and Cr (VI) adsorption were studied. The activated carbons were characterized by pore size distribution, surface area, FTIR, and SEM-EDX analysies. Based on the results, HCl leaching pretreatment of the biomass increased the activated carbon adsorption capacity of Cr (VI) from 114 to 190 mg g−1. The treatment of biomass with alkali and alkali earth metal salts, especially MgCl2, remarkably increased the activated carbon adsorption capacity of Pb (II) from 233 to 1430 mg g−1. The results indicated that Pb (II) adsorption was attributed to both the mesoporous structure of activated carbon and the abundance of Mg on the activated carbon's surface. On the other hand, the micropores played a major role in Cr (VI) adsorption capacity. The development of the micro- or mesoporous structure of activated carbons through pretreatment of lignocellulosic precursor could be an approach for providing high performance activated carbons for Pb (II) and Cr (VI) removal from aqueous solutions.

Особливості гніздобудування вивірки лісової (Sciurus vulgaris) в умовах Кам’янця-Подільського

Research on the biotopic distribution, abundance, and specific nesting features of the European red squirrel (Sciurus vulgaris) was carried out from October 2016 until May 2017 in the entire area of Kamianets-Podilskiy (Khmelnitskiy Oblast, Ukraine). By its construction type and tree vegetation, the following biotopes were singled out in the town area: one-storey buildings, multi-storey buildings, mixed housing types, parks, industrial area, the Smotrych river’s canyon, and gardening area. In total, 272 nests of the European red squirrel were registered, including 89 nests in parks (32.7 % of the total number of nests), 79 in the industrial area (29.0 %), 49 in the mixed housing area (18.0 %), 19 in the area of multi-storey buildings (7.0 %), 13 in the area of one-storey buildings (4.8 %), 12 in the gardening area (4.4 %), and 11 in the canyon of the Smotrych river (4.0 %). In Kamianets-Podilskiy and its surroundings, 178 178 pairs of the European red squirrel were recorded, what makes up 65.4 % of the number of registered nests. The population density (pair/km2) of the red squirrel in Kamianets-Podilskiy is 6.4 pairs/km2. The highest density was observed in the forest-park area (43.3 pairs/km2), in the canyon of the Smotrych river (10.7 pairs/km2), and in the area multi-storey buildings (9.1 pairs/km2). Squirrel nests were observed on 21 tree species, including the linden Тіlіа sp., the asp Populus sp., the chestnut Aesculus hippocastanum, the sycamore tree Acer tataricum, the field maple Асеr саmреstrе, the elm tree Ulmus laevis, the sweet cherry Prunus sp., the maple Acer negundo, the fir tree Рісеа sp., the walnut tree Juglans regia, the horn beech Саrріnus bеculus, the willow Salix alba, the acacia Robinia pseudoacacia, the ash tree Frахіnus ехсеlsіоr, the birch tree Betula sp., the poplar Populus sp., the pyramidal poplar Populus pyramidalis, the cedar Thuja occidentalis, the Norway maple Acer platanoides, the honey locust Gleditsia triacanthos, and the oak Quеrсus rоbur. Most nests were located on the pyramidal poplar (24.1 %), linden (19.7 %), and Norway maple (13.7 %), while the least number of nests was found on the fir tree (0.8 %) and chestnut (0.8 %). The European red squirrel usually arranges its nests at the height of 3.5 m to 23 m, in average 9.3 m. The specific features of location of squirrel nests depend on the tree species (the highest nests being located on the ash tree, pyramidal poplar, and the lowest nests being on the fir tree and cedar). The squirrel mostly arranges its nests at whorls usually made up of 3–4 branches (51.9 %), near the trunk (32.7 %), on the branches (13.0 %) and between trunks (2.4 %).

Urban Green Infrastructure Monitoring Using Remote Sensing from Integrated Visible and Thermal Infrared Cameras Mounted on a Moving Vehicle.

Climate change forecasts higher temperatures in urban environments worsening the urban heat island effect (UHI). Green infrastructure (GI) in cities could reduce the UHI by regulating and reducing ambient temperatures. Forest cities (i.e., Melbourne, Australia) aimed for large-scale planting of trees to adapt to climate change in the next decade. Therefore, monitoring cities’ green infrastructure requires close assessment of growth and water status at the tree-by-tree resolution for its proper maintenance and needs to be automated and efficient. This project proposed a novel monitoring system using an integrated visible and infrared thermal camera mounted on top of moving vehicles. Automated computer vision algorithms were used to analyze data gathered at an Elm trees avenue in the city of Melbourne, Australia (n = 172 trees) to obtain tree growth in the form of effective leaf area index (LAIe) and tree water stress index (TWSI), among other parameters. Results showed the tree-by-tree variation of trees monitored (5.04 km) between 2016–2017. The growth and water stress parameters obtained were mapped using customized codes and corresponded with weather trends and urban management. The proposed urban tree monitoring system could be a useful tool for city planning and GI monitoring, which can graphically show the diurnal, spatial, and temporal patterns of change of LAIe and TWSI to monitor the effects of climate change on the GI of cities.

Main pests of the elm (Ulmaceae) tree and their bioecological characteristics

This paper defines the types of elm trees pests in the Khorezm province in Uzbekistan, carries out their systematic analysis, and also determines the degree of their occurrence, as well as their natural types of enemies. The main phytophagous pests of elm trees in the Khorezm province belong to 4 genera and 14 species from 8 families. The vast majority of these pest species have been identified as Coleoptera pests. Pests were found to be mainly species that infect the body part of elm trees. In addition, 10 species of wild and parasitic entomophagous species have been identified as natural enemies. These species are phytophagous during the growing season and are important in managing their quantity.

Endophyte inoculation enhances Ulmus minor resistance to Dutch elm disease

Certain fungal endophytes improve plant resistance to biotic stresses in forest trees. In this study, three stem fungal endophytes belonging to classes Cystobasidiomycetes, Eurotiomycetes and Dothideomycetes were selected from 210 isolates for their potential as enhancers of Ulmus minor resistance to Ophiostoma novo-ulmi. We evaluated phenotypic traits of these endophytes that could be beneficial for inhibiting O. novo-ulmi in the host plant. Under in vitro conditions, the Dothideomycetous isolate YCB36 strongly inhibited O. novo-ulmi growth, released antipathogenic VOCs, chitinases and siderophores, and overlapped with the pathogen in nutrient utilization patterns. These functional traits could explain the 40% reduction in leaf wilting due to O. novo-ulmi in elm trees pre-inoculated with this endophyte. Ulmus minor trees inoculated with this endophyte showed increased leaf stomatal conductance and higher concentrations of flavonoids and total phenolic compounds in xylem tissues, suggesting induction of defence metabolism.

A new corticolous species of Mycena sect. Viscipelles (Basidiomycota: Agaricales) from the bark of a Living American elm tree in Texas, U.S.A.

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.

Indirect Effects of Grazing on Wind-Dispersed Elm Seeds in Sparse Woodlands of Northern China

Grazing leads to the reduction of biomass and plays a critical role in land degradation in arid and semiarid lands. However, the indirect effects of grazing on the ecosystem, e.g., the effect on seed dispersal, have not been well understood. In this study, we built an agent-based model (ABM) to simulate how grazing intensity affects the seed dispersal of elm trees, one of the native vegetation species of temperate woodlands in semiarid lands. The simulated results from the ABM and observed data from the real world were compared to assess the accuracy and validity of the ABM. The results show that elm seed densities in non-grazing, light, moderate, and heavy grazing lands were 74.97 ± 1.44, 57.63 ± 0.89, 37.73 ± 0.95, and 0.97 ± 0.05 seeds m−2, respectively—an apparently decreasing trend. Moreover, as grazing intensity increased, the values of nugget, sill, and partial sill decreased and the value of the ratio of nugget to sill increased. This study indicates that the grazing indirectly leads to the reduction of elm seed density and the increase of spatial heterogeneity of elm seed on the ground in sparse elm woodlands. Moreover, values of geostatistical indices from the ABM were not significantly different from field observation data except for the ratio of nugget to sill. It shows that ABMs can reasonably replicate the spatial pattern of elm seed densities in the field and thus are useful for simulating long-distance seed dispersal in sandy lands. This finding suggests that the indirect effects of grazing should be considered to effectively protect sparse elm woodlands.

Ecological stability of wood species in conditions of root reclamation of salt flats

The state of artificial tree planting in 54 years after the meliorative effects on the solonetzic soils (land use, gypsum, manure application) and the transformation of annual soil treatments were studied. There was a general decrease in the forest stand and its quality on saline cells compared to common Chernozem. It is shown that the most salt-resistant tree crops are oak, ash and elm, whose safety is higher compared to other breeds tested in the experiment. Pears, apple trees, and poplars are now almost absent from the forest plantation. In the southern part of the saline section, by the age of 54, an ash-oak plantation with poplar and elm trees was formed (in the aggregate of the first two tiers), and in the Chernozem section, an oak-ash plantation with elm trees was formed. Plantings, according to forest management standards, have a significant difference in the composition of the first tier, in the completeness and totality of crowns and the stock of the stem tree. In the Northern part of the experimental site, the difference in the composition of the first two tiers is more significant, since the proportion of ash in the Chernozem section is 20% lower than in solonetzic soils, where the stand is less dense, full, stock and bonitet than the taxational indicators of the stand in Chernozem.

Genetic variation, phylogenetic relationship and spatial distribution of \u2018Candidatus Phytoplasma ulmi\u2019 strains in Germany

A recent survey in Germany revealed the wide presence of ‘Candidatus Phytoplasma ulmi’ in native elm stands. Accessions were studied for their genetic variability and phylogenetic relationship based on the conserved groEL and the variable imp gene. While the groEL sequences revealed a high intraspecific homology of more than 99%, the homology of the imp gene dropped to 71% between distantly related sequences. Twenty-nine groEL and 74 imp genotypes were distinguished based on polymorphic sites. Phylogenetic analysis of the groEL gene clustered all ‘Ca. P. ulmi’ strains and separated them from related phytoplasmas of the 16SrV group. The inferred phylogeny of the imp gene resulted in a different tree topology and separated the ‘Ca. P. ulmi’ genotypes into two clusters, one closely related to the flavescence dorée phytoplasma strain FD-D (16SrV-D), the other affiliated with the flavescence dorée phytoplasma strains FD-C and FD70 and the alder yellows phytoplasma (16SrV-C). In both phylograms, ‘Ca. P. ulmi’ genotypes from Scots elm trees formed a coherent cluster, while genotypes from European white elms and field elms grouped less strictly. The regional distribution pattern was congruent for some of the groEL and imp genotypes, but a strict linkage for all genotypes was not apparent.

Foundation species across a latitudinal gradient in China.

Foundation species structure forest communities and ecosystems but are difficult to identify without long-term observations or experiments. We used statistical criteria--outliers from size-frequency distributions and scale-dependent negative effects on alpha diversity and positive effects on beta diversity--to identify candidate foundation woody plant species in 12 large forest-dynamics plots spanning 26 degrees of latitude in China. We used these data (1) to identify candidate foundation species in Chinese forests, (2) to test the hypothesis--based on observations of a midlatitude peak in functional trait diversity and high local species richness but few numerically dominant species in tropical forests--that foundation woody plant species are more frequent in temperate than tropical or boreal forests, and (3) to compare these results with data from the Americas to suggest candidate foundation genera in northern hemisphere forests. Using the most stringent criteria, only two species of Acer, the canopy tree Acer ukurunduense and the shrubby treelet Acer barbinerve, were identified in temperate plots as candidate foundation species. Using more relaxed criteria, we identified four times more candidate foundation species in temperate plots (including species of Acer, Pinus, Juglans, Padus, Tilia, Fraxinus, Prunus, Taxus, Ulmus, and Corlyus) than in (sub)tropical plots (the treelets or shrubs Aporosa yunnanensis, Ficus hispida, Brassaiopsis glomerulata, and Orophea laui). Species diversity of co-occurring woody species was negatively associated with basal area of candidate foundation species more frequently at 5- and 10-m spatial grains (scale) than at a 20-m grain. Conversely, Bray-Curtis dissimilarity was positively associated with basal area of candidate foundation species more frequently at 5-m than at 10- or 20-m grains. Both stringent and relaxed criteria supported the hypothesis that foundation species are more common in mid-latitude temperate forests. Comparisons of candidate foundation species in Chinese and North American forests suggest that Acer be investigated further as a foundation tree genus.