Quercus Muehlenbergii Research Articles

Age, growth, longevity, and post-fire/thinning response of chinkapin oak seedlings in a Kansas upland hardwood forest1

Thinning and prescribed fire are often used to promote oak recruitment into the canopy; however, little is known about the longevity of resprouting oak seedlings and how age affects growth response to these treatments. We investigated this by excavating 180 chinkapin oak seedlings (Quercus muehlenbergii) from an eastern Kansas upland hardwood forest study area divided into different combinations of burning and thinning treatments: control, burn only, burn and thin to 7 m2/ha, burn and thin to 14 m2/ha, thin to 7 m2/ha, and thin to 14 m2/ha. In each treatment, approximately three years post-treatment, we aged the seedlings at the root collar (“root age”) and the base of the current aboveground shoot using tissue staining and microscopy techniques. Annual shoot growth rate was calculated for each individual based on the age of the shoot and its total height. We compared these shoot growth rates in height across treatments and investigated this relationship as a function of plant age using the root age. The oldest root age was 48 yr, and 20% of the roots were ≥ 18 yr. Mean root age of advance reproduction was 11.8 years, while mean age of associated aboveground stems was 4.1 yr, with the oldest age structure belonging to treatments without any burn with the control being the oldest. The majority (90%) of the mismatch between root and shoot age was associated with burn treatments. Root age had a strong positive correlation with shoot growth rate in the burn + thinning treatments and also the untreated control, suggesting that age becomes an influence on growth when resprouting under adequate light conditions but also when individuals experience low competition. Further determination of root age structures, such as along gradients of site productivity, would likely aid in further understanding regeneration dynamics and management for sustaining oaks.

Measurement of photosynthesis in excised leaves of ornamental trees: a novel method to estimate leaf level drought tolerance and increase experimental sample size

Measuring gas exchange on excised ornamental tree leaves may be a rapid and accurate method to study leaf-level drought tolerance, and greatly increase experiment sample size. Drought is a common phenomenon in arid and semi-arid urban environments. Because water is valuable and limited in these environments, it is crucial to study drought tolerance of ornamental tree species used in urban forests. In a first of its kind study, we observed leaf-level drought tolerance using photosynthetic decline curves in excised leaves of seven ornamental urban tree species: Shantung maple (Acer truncatum), Mexican redbud (Cercis canadensis mexicana), Texas redbud (C. canadensis texensis), White redbud (C. canadensis texensis ‘Alba’), Oklahoma redbud (C. canadensis texensis ‘Oklahoma’), Chinquapin oak (Quercus muehlenbergii), and English oak (Q. robur). For both excised and non-excised treatments, two leaves from the same tree were simultaneously clamped into cuvettes of two Li-Cor LI 6400 XT portable photosynthetic systems. For the excision treatment, the leaf was excised from the branch at 120 s. By comparing photosynthetic decline curves from excised leaves with their non-excised counterparts, we found Mexican redbud and White redbud leaves take a longer period of time (450 s. and 360 s., respectively) compared to English oak leaves (90 s.) to show a significant decline in photosynthetic gas exchange. This technique also proposes a solution to a common problem faced by many plant researchers. While using the leaf excision technique on large trees, we were able to significantly increase sample size with rapidity and accuracy. Thus, we suggest measuring gas exchange on excised leaves of select ornamental tree species as a rapid and accurate method to estimate leaf-level drought tolerance, and greatly increase the number of samples measured in a given time period.

Biogeomorphic keystones and equivalents: Examples from a bedrock stream

AbstractBiogeomorphic keystone species profoundly impact landscapes, such that their introduction or removal would cause fundamental changes in geomorphic systems. This paper explores the concept of biogeomorphic keystone species by examining the general vs. species‐specific biogeomorphic impacts (BGIs) of trees on a limestone bedrock‐controlled stream, Shawnee Run, in central Kentucky. Field investigation identified three strong BGIs: (i) biogeomorphic pool formation via bioweathering; (ii) root bank‐associated bioprotection; and (iii) avulsion‐originated island development linked to bioprotection. This research evaluates these impacts in the context of keystone or other biogeomorphic roles. A field survey was conducted on nine stream reaches, each consisting of 10–12 hydraulic units of riffle, pool, and run. Results suggest that American sycamore (Platanus occidentalis) plays a keystone role by promoting the development of ~42% of pools in the study area. While geomorphic pools are formed by fluvial process–form linkages, these biogeomorphic pools are developed by sycamore root‐induced channel bed bioweathering. Only American sycamore and chinquapin oak (Quercus muehlenbergii) exhibited root‐bank development amongst 15 different species identified – and thus play a vital role in bank bioprotection. Lastly, trees can promote avulsion‐originated island formation by creating erosion‐resistant bioprotective patches. Mature trees (in terms of size), particularly large American sycamore and chinquapin oak, dominate Shawnee Run islands with a mean diameter at breast height (DBH) > 40 cm. However, other trees can provide comparable bioprotection, particularly at mature stages. Because its absence would result in fundamentally different stream morphology, sycamore can be considered a biogeomorphic keystone species in Shawnee Run. © 2020 John Wiley & Sons, Ltd.

Place of Cladrastis kentukea (Dum.-Cours.) Rudd in natural and cultural phytocenoses

Aim. The work is devoted to the comparative analysis of plant communities, soil and climatic conditions of natural and cultivated habitats of C. kentukea. The obtained results will allow us to offer suitable ecological conditions for cultivationof this species and to select plants that can successfully exist in artificial phytocenosis together with C. kentukea. Methods. The method of complex analysis of vegetation, climatic and soil conditions of natural and cultivated habitats of C. kentukea was used. The description of C. kentukea habitats in culture was made using an expeditionary survey of the botanical gardens and dendrological parks of the Right-bank Forest-Steppe of Ukraine. Results. A comparative analysis of the climatic and soil conditions of the study areas showed that there is a significant difference between the natural and thecultigenic habitats. The natural range is characterized by 2.5 times higher rainfall and twice the average air temperature. The natural habitat of C. kentukea, concentrated in the southeastern part of the North American continent, belongs to a large and monolithic subtropical moist forest sector of yellow soil, red soil and associated gleyed eluvial soil and subtropical ashen-gray soil. The Right-bank Forest-Steppe of Ukraine is dominated by degraded black podzolic soil, gray and dark gray podzolic forests soils. C. kentukea grows in the second tier of mixed deciduous forests in the natural habitat, the plants of this species do not form solid arrays, it occurs by separate localities. The C. kentukea cultivation habitat is extensive, the plants occur in collections of botanical gardens and parks in Europe and Central Asia. When creating durable ornamentalartificial phytocoenoses with the participation of C. kentukea, the optimal spatial placement of plants should be observed and a multilayered planting structure should be formed. Conclusions. Comparative analysis of climatic and soil conditions of natural and cultured habitats showed a significant difference between the average long-term air temperature and the average long-term rainfall in the explored areas. We have found out that plants of the species C. kentukea under cultivated habitat in the Right-bank Forest-Steppe of Ukraine are characterized by complete acclimatization, which indicates the ecologicalplasticity of the plants. In the North American natural range, C. kentukea occurs mainly in the associations of Quercus alba — Quercus rubra — Acer rubrum — Acer saccharum — Carya ovata (also described as Acer saccharum — Quercusmuehlenbergii — Cotinus obovatus), Fagus grandifolia — Acer saccharum — Quercus rubra — Quercus velutina and Quercus muehlenbergii — Carya carolinae-septentrionalis — Acer barbatum — Juniperus virginiana — Crotonalabamensis. In artificial phytocenoses of the Right-bank Forest-Steppe,plants of C. kentukea species grow successfully with Acer platanoides L., Ulmus laevis Pall., Tilia cordata Mill., Fraxinus excelsior L., Aesculus hippocastanum L. and Carpinus betulus L.

Prescribed fire effects on oak woodland advance regeneration at the prairie–forest border in Kansas, USA

Understanding the effects of fire on advance regeneration of oak (Quercus L.) species and their competitors is an important step in determining the role of prescribed fire in regenerating and restoring upland oak ecosystems. Our study aimed to understand how dormant-season prescribed fire affects advance regeneration of chinkapin oak (Quercus muehlenbergii Engelm.), black oak (Quercus velutina Lam.), and their major competitors at sites targeted for woodland restoration and management. We analyzed relationships between stem size and survival probability; determined the effect of fire temperature on survival probability; and compared how mortality, sprouting, and survival differed among species. For chinkapin oak, black oak, and bitternut hickory (Carya cordiformis (Wangenh.) K. Koch), mortality was low and rate of sprouting was high after shoot dieback. Initial basal diameter was significantly related to survival probability after one fire for all species except chinkapin oak and black oak. Height was a significant predictor of survival probability for all species except chinkapin oak. Although sugar maple (Acer saccharum Marsh.) also responded to fire by sprouting, it did so at a much lower rate than oaks and hickory (20% versus 43%–68%). These data reveal that heavily invaded, fire-suppressed woodlands on the prairie–forest border region may not experience major structural and compositional shifts without repeated burning or mechanical treatments.

Forty-Eight Years of Forest Succession: Tree Species Change across Four Forest Types in Mid-Missouri

In the central and eastern United States, many forest ecosystems have undergone recent shifts in composition and structure that may conflict with contemporary management objectives. Long-term forest inventory data were used to determine patterns of forest succession over a 48-year period for four forest types in mid-Missouri: bottomlands, dry ridge and slope, glade-like, and mesic slopes. All forest types increased in stand basal area and overstory quadratic mean diameter through time, with concomitant decreases in the number of midstory trees. Sugar maple (Acer saccharum Marshall) increased in importance value on dry ridge and slope and mesic slope forest types, largely due to the accumulation of trees in smaller diameter classes. White oak (Quercus alba L.) increased in overstory basal area in dry ridge and slope plots through the duration of the study, whereas black oak (Quercus velutina Lam.) and Shumard oak (Quercus shumardii Buckley) decreased in overstory density and basal area through time. Oak stems were nearly absent from the midstory across forest types in the recent sampling, suggesting future challenges for maintaining oak-dominated canopies following attrition of canopy trees through time on upland forest types. In glade-like plots, eastern redcedar (Juniperus virginiana L.) increased in both overstory density and basal area through time, and Shumard oak decreased in density. The importance value of chinkapin oak (Quercus muehlenbergii Engelm.) in the overstory decreased through time in glade-like plots, largely due to the increase in density of eastern redcedar rather than the loss of chinkapin oak from the overstory. The patterns of succession in this forest landscape of mid-Missouri suggest that forest management may be needed to address two common contemporary concerns: (1) the need for increasing oak advance reproduction and recruitment to maintain oak as a canopy species; and (2) reducing eastern redcedar encroachment for glade restoration and management.

Gas exchange and growth of landscape tree species in response to drought and post establishment applied organic mulch

Landscape industry employees often advises homeowners to place organic mulches on soils surrounding trees in new and existing landscapes. However, limited research has been conducted to determine if organic mulch placed below established landscape trees enhances tree growth. Under non-irrigated conditions, our research objective was to compare gas exchange and growth of established landscape trees that either had, or did not have organic mulch placed on the soil surface surrounding each tree. English oak (Quercus robur), Chinquapin oak (Q. muehlenbergii), and Shantung maple (Acer truncatum) trees were planted 2002. In Fall 2008, six trees of each species were randomly assigned a mulch treatment: organic mulch or no organic mulch placed on the soil below the tree canopy. From Fall of 2008 through Fall of 2011 trees received weekly irrigation. Beginning 2012, trees were not irrigated. Daily weather data were collected by an onsite weather station. Throughout the 2012, 2013, and 2014 growing seasons bud break data was collected from each tree. In addition, throughout each growing season mid-day gas exchange data (stomatal conductance, photosynthetic rate, etc.) were collected. At the end of each growing season, growth data were assessed. Data indicate soil under mulch was cooler, had greater soil moisture, and less extreme temperature fluctuations extremes when compared to soil without mulch. Throughout the experiment, species and treatment differences were found in gas exchange data. Shoot growth tended to be greater for non-mulch trees. However, leaf area varied between species and mulch treatments. Results suggest benefits (greater gas exchange, growth, etc.) of organic mulch placed under non-irrigated established trees is species specific, and should be carefully considered prior to making recommendations.

A Comparison of Seed Predation, Seed Dispersal, and Seedling Herbivory in Oak and Hickory: Species with Contrasting Regenerating Abilities in a Bluegrass Savanna—Woodland Habitat

Abstract Quercus (oak) regeneration failure threatens many forest and savanna communities worldwide, where preservation of vegetation structure and composition depends on acorns germinating and surviving into adulthood. However, predation on the acorns and browsing of seedlings limits oak regeneration. To better understand the effects of these 2 mechanisms on oak recruitment in the endangered Bluegrass savanna—woodland of Kentucky, we compared seed predation and herbivory on Quercus muehlenbergii (Chinquapin Oak) with Carya laciniosa (Shellbark Hickory), a successfully regenerating tree species. Compared to hickory nuts, acorns were predated more, cached less, and dispersed shorter distances. Neither the distribution of the seedlings under the parent canopy nor browse damage differed between the 2 species. Our results suggest that seed-predation prevents regeneration of oaks in this endangered community.

Biogeomorphology and contingent ecosystem engineering in karst landscapes

While karst is not biogenic in the same sense as, say, coral reefs or peat bogs, and carbonate dissolution can occur abiotically, formation of karst landscapes would not occur in the absence of the biosphere. Seven levels of biogeomorphic biotic-abiotic interactions are identified, from indirect impacts to landforms as extended phenotypes. Karst is generally near the biogenic end of that spectrum, featuring reciprocal interactions and mutual adjustments between biota and landforms and interrelated geomorphological and ecological processes. Karst biogeomorphology may also involve niche construction. In many cases biogeomorphic ecosystem engineering in karst is contingent, in the sense that the engineer organisms may have no, or different, biogeomorphic impacts in non-karst environments. Several examples of contingent ecosystem engineering in karst are given, including biogeomorphic effects of chinkapin oak. Abiotic geomorphic features exist on Earth, but consideration of landform types lying between the biotic-abiotic extremes would likely yield broadly similar conclusions to those about karst. However, it is also clear that we know very little about niche construction and coevolution in karst biogeomorphology, and whether karst or any specific karst features can be considered an extended (composite) phenotype is still an open question. Thus far, most work on biogeomorphology and ecosystem engineering has focused on what might be called obligate engineers—organisms whose engineering effects are at least inevitable, if not necessary to their survival. However, in some cases contingent ecosystem engineers have substantial geomorphic impacts.

Screening Oak Hybrids for Tolerance to Alkaline Soils

This study evaluated a diverse range of oak (Quercus) hybrids for tolerance to alkaline soils, which is a common site condition in urban landscapes that often limits the growth and longevity of many tree species. Different oak hybrids display varying severities of iron-deficiency induced leaf chlorosis when grown in a highly alkaline medium. Severity of leaf chlorosis was found to vary between different maternal parent species, with the results suggesting that hybrids with the maternal parents Q. macrocarpa (bur oak), possibly Q. muehlenbergii (chinkapin oak), and Q. ‘Ooti’ (ooti oak), are more likely to maintain healthy green leaf color when growing in a highly alkaline medium. These findings suggest that breeders interested in developing oak hybrids that are both cold-hardy and tolerant of alkaline soils should utilize these species in their crosses, and avoid Q. bicolor (swamp white oak), hybrids of which were generally found to be intolerant of alkaline soil. This study is one phase of a long-term project underway at Cornell University's Urban Horticulture Institute to select superior urban-tolerant cultivars of oak hybrids for future introduction into the horticulture industry.

The impact of the invasive shrubLonicera maackiion the decomposition dynamics of a native plant community

Invasive plants may have variable effects within a given environment depending on their interactions with the dominant native species, yet little research has examined such species-species interactions within a site. Savanna trees with nonoverlapping canopies offer an ideal opportunity to assess associated changes in the ecosystem processes that result from interactions between an invasive species and different native tree species. We examined the influence of the exotic invasive shrub Lonicera maackii on decomposition dynamics under three native tree species: Fraxinus quadrangulata, Quercus muehlenbergii, and Carya ovata. Litter decomposition rates and litter C and N were evaluated over two years using single- and mixed-species litterbags (L. maackii and individual tree species litter); microarthropod abundance was measured at 6 weeks using Tulgren funnels. Litter from the invasive L. maackii decomposed and lost N more rapidly than the litter of the three native tree species. The rate at which L. maackii decomposed depended on its location, with L. maackii litter decomposing and losing N more rapidly under C. ovata than under the other two native tree species. Mixing L. maackii with the native species' litter did not accelerate litter mass loss overall but did result in synergistic N losses at variable times throughout the experiment, further highlighting the variable interaction between native species and L. maackii. Nitrogen loss was significantly higher than expected in mixtures of C. ovata + L. maackii litter at 6 weeks, in F. quadrangulata + L. maackii litter at 12 weeks, and in Q. muehlenbergii + L. maackii litter at 24 weeks. If the effects of invasive species on certain ecosystem processes, such as litter decomposition, are strongly influenced by their association with native species, this could suggest the need for a more nuanced understanding of the vulnerability of ecosystem processes to invasions of L. maackii and potentially other invasive species.

Forest Composition and Structure on Glade-forming Limestones in Middle Tennessee

ABSTRACT Within a successional context, the vegetation associated with the cedar glade ecosystem in middle Tennessee develops from bare limestone bedrock to subclimax redcedar, preclimax oak-hickory, and climax mixed hardwood forests. Studies on the composition and structure of forests associated with cedar glade–forming limestones (Lebanon, Ridley) are rare. We sampled the canopy and understory of six forest stands in middle Tennessee on these limestones. Observed number of canopy species was 14–24 across stands; estimated richness was greater by 1–3 species (bootstrap) or 3–6 species (first-order jackknife) than observed richness. With the exception of Ailanthus altissima in one stand, all other canopy species were native. Juniperus virginiana, Fraxinus americana, Carya ovata, and Quercus muehlenbergii were primary canopy components in 4 or 6 stands, and C. glabra, Q. shumardii, Ulmus alata, F. quadrangulata, Q. alba, and Q. velutina in 2–3 stands. When we included stands from a previously published s...

Response of advance reproduction of oaks and associated species to repeated prescribed fires in upland oak-hickory forests, Missouri

The Chilton Creek prescribed burn project was initiated in 1996 by The Nature Conservancy (TNC) to restore native oak woodlands and test the effect of frequent, low intensity surface fires conducted in the dormant season (March–April) on upland oak-hickory forests in the Ozarks of Missouri. Burning treatments on five sites totaling 1000 ha were initiated in 1998. The prescribed burn treatments included: annual burns (one site was burned annually) and periodic burns (four sites were burned with a mean fire return interval of approximately 4 years). Approximately 3000 stems of advance reproduction with basal diameters ⩽15.0 cm were measured in 1997 (pre-burn), and remeasured in 1998, 2001 and 2007 as the prescribed burn treatments proceeded. Mortality and changes in average and aggregate total height between 1997 and 2007 were analyzed for fourteen selected tree species. Over a ten-year period prescribed burning reduced stem density, mean height and aggregate height by 57%, 36% and 67%, respectively. However, individual tree species responded differently to the repeated burns. Oaks exhibited moderate mortality (36–54%) compared to hickories, sassafras and winged elm, all of which experienced relatively low mortality (18–35%). Flowering dogwood, shortleaf pine, blackgum and other minor species incurred higher mortality (60–76%). Oaks generally had slightly lower reductions in mean height and aggregate height than associated species with the exception of shortleaf pine, but the differences were mostly non-significant. Repeated burning tended to favor the white oak species (white oak, post oak, chinkapin oak) more than the red oak species (black oak, scarlet oak), although the differences were minor. Shortleaf pine was the only species to show increases in mean height following the ten-year period of prescribed burning. Effects of repeated burns on mortality of advance reproduction changed with stem size (e.g., basal diameter, total height). A logistic model quantified mortality changes as a function of the ratio between total stem height and the square of stem basal diameter. Based on this model, fourteen species were classified into four groups characterized by model intercept and slope: group 1: high intercept and high slope (shortleaf pine, flowering dogwood); group 2: high intercept and low slope (blackgum, other minor species); group 3: low intercept and low slope (sassafras, winged elm, black and pignut hickories); and group 4: low intercept and high slope (oaks, mockernut hickory). Species in groups 3 and 4 are more resistant to repeated fires than those in groups 1 and 2 as indicated by their lower mortality, particularly for stems with larger basal diameters. Among species in groups 3 and 4, oaks will likely be favored over the long term because of their conservative reproduction strategies as suggested by the significance of the regression coefficients for slope. If large advance reproduction is present, shortleaf pine will likely survive repeated low intensity fires and maintain its height and competitive position due to its ability to avoid shoot dieback.

Relationship between ultrasonic properties and structural changes in the mesophyll during leaf dehydration

The broad-band ultrasonic spectroscopy technique allows the determination of changes in the relative water content (RWC) of leaves with contrasting structural features. Specifically, the standardized frequency associated with the maximum transmittance (f/f(o)) is strongly related to the RWC. This relationship is characterized by the existence of two phases separated by an inflexion point (associated with the turgor loss point). To obtain a better understanding of the strong relationship found between RWC and f/f(o), this work has studied the structural changes experienced by Quercus muehlenbergii leaves during dehydration in terms of ultrasounds measurements, cell wall elasticity, leaf thickness, leaf density, and leaf structure. The results suggest that the decrease found in f/f(o) before the turgor loss point can be attributed to the occurrence of changes in the estimation of the macroscopic effective elastic constant of the leaf (c(33)), mainly associated with changes in the bulk modulus of elasticity of the cell wall (ε). These changes are overriding or compensating for the thickness decreases recorded during this phase. On the other hand, the high degree of cell shrinkage and stretching found in the mesophyll cells during the second phase seem to explain the changes in the acoustic properties of the leaf beyond the turgor loss point. The formation of large intercellular spaces, which increased the irregularity in the acoustic pathway, may explain the increase of the attenuation coefficient of ultrasounds once the turgor loss point threshold is exceeded. The direct measurement of c(33) from ultrasonic measurements would allow a better knowledge of the overall biomechanical properties of the leaf further than those derived from the P-V analysis.

Fire resistance of tree species explains historical gallery forest community composition

Fire, climatic variability, and grazing by large herbivores have historically limited woody vegetation in the tallgrass prairie region of North America to gallery forests in protected areas along rivers and streams. Fire, in particular, has been a strong selective pressure against woody vegetation. Consequently, we expect that dominant tree species in these forests have developed mechanisms for tolerating periodic surface fires. Susceptibility of trees to fire damage depends in part on key properties of bark which influence heat transfer to the vascular cambium, including thickness, density, and moisture content. An historical (1983) survey of Konza Prairie Biological Station in northeast Kansas, USA indicated that gallery forests were co-dominated by Quercus macrocarpa and Quercus muehlenbergii, while Celtis occidentalis occurred as an important sub-dominant species. Populus deltoides, Gleditsia triacanthos, and Juniperus virginiana were relatively uncommon. To test the hypothesis that historically dominant gallery forest tree species are more resistant to fire damage than uncommon species, fire was applied to the bark of 10 individuals of each of these six species under conditions mimicking surface fires (400 °C for 120 s). Maximum temperature at the vascular cambium, bark thickness, bark moisture content, and bark density were measured. Trees were considered fire-resistant if the vascular cambium temperature remained below the thermal cell death threshold, 60 °C, throughout the treatment. Using logistic regression, bark thickness was found to be a significant predictor of lethal cambium temperatures ( P = 0.002), while neither bark density nor moisture content were significantly related to lethal cambium temperature ( P = 0.279 and P = 0.131, respectively). Across species, a minimum bark thickness of approximately 8.6 mm was necessary to maintain the vascular cambium temperature below 60 °C. Trees that produce thick bark quickly in juvenile size classes ( P. deltoides, Q. macrocarpa, and Q. muehlenbergii) experienced lower temperatures at the vascular cambium than those which do not develop thick bark with increasing diameter ( C. occidentalis, G. triacanthos, and J. virginiana). Ranking these tree species by either the DBH or age needed to develop the minimum protective bark thickness largely agreed with ranking based on historical relative importance. As fire frequency and intensity decrease in remnant tallgrass prairie of North America as a result of habitat fragmentation, fire suppression, and changing land management, fire-sensitive species may increase in relative importance in gallery forests because of increased juvenile survival.

Survival and reproduction of lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) on flora associated with native habitats in Kansas

Capture of Rhyzopertha dominica in pheromone-baited traps located many kilometers away from grain storage suggests that this species may be exploiting non-grain food sources. To investigate the potential for survival of this species on alternative hosts in the absence of grain, we conducted no-choice feeding assays with twigs and seeds of trees, and seeds of grasses, forbs, and shrubs, commonly encountered on Kansas prairie landscapes where R. dominica has been captured. In addition, R. dominica development and progeny production were assessed on seeds that adults were able to survive on for at least two weeks. Adult survival was poor on grass and forb seeds, although 13.4% of individuals survived on Elymus canadensis, Canada wildrye, seeds after two weeks, compared with 80.3% on Triticum aestivum, wheat, and 0.0% survival in the absence of food. Beetles readily tunneled into twigs from a wide range of tree species, but survival was generally low. A few individuals survived up to four weeks on Gleditsia triacanthos, honey locust. In contrast, bioassays showed that R. dominica could survive and reproduce on damaged seeds (acorns) of six species of oak, but not on undamaged seeds. For example, survival was 95.8% on damaged Quercus muehlenbergii, chinquapin oak. A survey of acorns at the original field collection site showed that the majority of the acorns on the ground had been cracked or bored into by insects and small mammals. Furthermore, we recovered three R. dominica adults from acorns collected in the field and held in sealed containers in the laboratory. These findings suggest that R. dominica populations in Kansas can persist on wild acorns when grain is not available.

Oak decline in the Boston Mountains, Arkansas, USA: Spatial and temporal patterns under two fire regimes

A spatially explicit forest succession and disturbance model is used to delineate the extent and dispersion of oak decline under two fire regimes over a 150-year period. The objectives of this study are to delineate potential current and future oak decline areas using species composition and age structure data in combination with ecological land types, and to investigate how relatively frequent simulated fires and fire suppression affect the dynamics of oak decline. We parameterized LANDIS, a spatially explicit forest succession and disturbance model, for areas in the Boston Mountains of Arkansas, USA. Land type distribution and initial species/age class were parameterized into LANDIS using existing forest data. Tree species were parameterized as five functional groups including white oak ( Quercus alba L., Quercus stellata Wangenh., Quercus muehlenbergii Engelm.), red oak ( Qurecus rubra L., Quercus marilandica Muenchh., Quercus falcata Michx., Quercus coccinea Muenchh.), black oak ( Quercus velutina Lam.), shortleaf pine ( Pinus echinata Mill), and maple ( Acer rubrum L., Acer saccharum Marsh.) groups. Two fire regimes were also parameterized: current fire regime with a fire return interval of 300 years and a historic fire regime with an overall average fire return interval of 50 years. The 150-year simulation suggests that white oak and shortleaf pine abundance would increase under the historic fire regime and that the red oak group abundance increases under the current fire regime. The black oak group also shows a strong increasing trend under the current fire regime, and only the maple group remains relatively unchanged under both scenarios. At present, 45% of the sites in the study area are classified as potential oak decline sites (sites where red and black oak are >70 years old). After 150 simulation years, 30% of the sites are classified as potential oak decline sites under the current fire regime whereas 20% of the sites are potential oak decline sites under the historic fire regime. This analysis delineates potential oak decline sites and establishes risk ratings for these areas. This is a further step toward precision management and planning.

Prevalence and association of the laboulbenialean fungus Hesperomyces virescens (Laboulbeniales: Laboulbeniaceae) on coccinellid hosts (Coleoptera: Coccinellidae) in Kentucky, USA

The laboulbenialean fungi occur throughout the world and are closely associated with a range of arthropods, including many coleopteran hosts. Throughout the summer of 2004, coccinellids were collected from a Bluegrass savanna woodland ecosys- tem, dominated by blue ash Fraxinus quadrangulata and Chinkapin Oak Quercus muehlenbergii, and the adults were examined for the presence of Hesperomyces virescens using binocular and scanning electron microscopy. Over 80% of adult Harmonia axyridis, a species previously reported as having a persistent association with the fungus, were infected. No significant differences were observed in incidence on male and female hosts, however, the distribution of fungus differed between sexes. Female H. axyridis had a greater percentage of infection on their elytron compared to other parts of their body whilst male infection was concentrated around their elytra, legs and abdomen. Although infection rates were significantly lower, we report, for the first time, the presence of this fungus on the hosts Cycloneda munda, Brachiacantha quadripunctata and Psyllobora vigintimaculata. This is the first study documenting the incidence of this insect-associated fungus with these native coccinellids of North America. In the samples collected from the Bluegrass savanna, two species (Coleomegilla maculata and Hyperaspis signata) were not infected by this fungus.

Ecological Factors Affecting the Distribution of Woody Vegetation Near the Arkansas River, Tulsa County

Ecological factors affecting plant distribution were studied over different rock strata and slope exposures above the Arkansas River, Tulsa County. Here the Wann sandstone caprock is underlain by the Iola limestone formation. The vegetation was analyzed taxonomically by a complete collection throughout one growing season. Belt transects crossing rock strata on all slope exposures permitted computation of parameters summarized by an Importance Percentage for each woody species. Differences in species populations and degree of mesophytism exist on the slope exposures. Sandstone upland dominants are post and blackjack oaks. Smoke-tree, rare in Oklahoma, and chinquapin oak are closely associated in limestone microhabitats, where each occupies a separate niche. The smoke-tree, of disjunct distribution, appears to be a relict of widespread occurrence in past geologic periods. Its survival with limited ecological amplitude is due to the continuance of the microhabitats to which it is so well adapted.

Restoration of a Forest Understory After the Removal of an Invasive Shrub, Amur Honeysuckle (Lonicera maackii)

Abstract The recruitment of native seedlings is often reduced in areas where the invasive Amur honeysuckle (Lonicera maackii) is abundant. To address this recruitment problem, we evaluated the effectiveness of L. maackii eradication methods and restoration efforts using seedlings of six native tree species planted within eradication and unmanipulated (control) plots. Two eradication methods using glyphosate herbicide were evaluated: cut and paint and stem injection with an EZ‐Ject lance. Lonicera maackii density and biomass as well as microenvironmental characteristics were measured to study their effects on seedling growth and survivorship. Mean biomass of Amur honeysuckle was 361 ± 69 kg/ha, and density was 21,380 ± 3,171 plants/ha. Both eradication treatments were effective in killing L. maackii (≥ 94%). The injection treatment was most effective on large L. maackii individuals (>1.5 cm diameter), was 43% faster to apply than cutting and painting and less fatiguing for the operator, decreased operator exposure to herbicide, and minimized impact to nontarget vegetation. Deer browse tree protectors were used on half of the seedlings, but did not affect survivorship or growth. After 3 years, survival of native seedlings was significantly less where L. maackii was left intact (32 ± 3%) compared with the eradication plots (p < 0.002). Seedling survival was significantly different between cut (51 ± 3%) and injected (45 ± 3%) plots. Species had different final percent survival and rates of mortality. Species survival differed greatly by species (in descending order): Fraxinus pennsylvanica > Quercus muehlenbergii ≥ Prunus serotina≥ Juglans nigra > Cercis canadensis > Cornus florida. Survivorship and growth of native seedlings was affected by a severe first‐year drought and by site location. One site exhibited greater spring soil moisture, pH, percent open canopy, and had greater survivorship relative to the other site (55 ± 2 vs. 30 ± 2%). Overall, both L. maackii eradication methods were successful, but restorationists should be aware of the potential for differential survivorship of native seedlings depending on species identity and microenvironmental conditions.