Bottomland Hardwood Forests Research Articles

Swainson's Warbler Breeding Distribution and Habitat Characteristics in Bottomland Hardwood Forests of the Lower Piedmont in North Carolina: Importance of Chinese Privet

The Piedmont physiographic province in southeastern North America generally comprises a large gap between low montane and Coastal Plain breeding populations of Limnothlypis swainsonii (Swainson's Warbler). I conducted land-based surveys of singing males during spring 2017–2018 in late-successional bottomland hardwood forests along and adjacent to accessible areas of the Great Pee Dee River in the Lower Piedmont of Anson and Richmond counties, NC. I located 38–41 territorial males each year and in 2018 measured 12 territories where birds were present both years. Arundinaria spp. (cane) culm counts among the 4 shrub subplots across all plots were low (median = 694/ha), and cane was absent from half of the 12 plots. In contrast, the dense understory within bottomland hardwood forests occupied by Swainson's Warblers was generally dominated by Ligustrum sinense (Chinese Privet). Chinese Privet was present in all plots and had high understory-stem counts (median = 32,539/ha), 55% of the total of the median of all small woody stems and cane culm counts (59,325/ha). Despite the replacement of native shrubs and cane by the riparian invasive Chinese Privet, this latter median count exceeds the recommended minimum count of understory-stems and culms (∼40,000/ha) for Swainson's Warbler breeding territories. This is the first study to document anywhere within Swainson's Warbler breeding range that Chinese Privet constitutes the most important habitat characteristic in bottomland hardwood forests. This study is also the first anywhere within the Piedmont to document that Swainson's Warbler is locally fairly common at the edge of their range along the Great Pee Dee River of North Carolina.

A record of flooding on the White River, Arkansas derived from tree-ring anatomical variability and vessel width

ABSTRACTTree rings preserve important records of past flooding. We present the results of an examination of inter-annual tree-ring anatomical variability and vessel width in overcup oak (Quercus lyrata) and river flooding at a bottomland hardwood forest site near the confluence of the White and Mississippi Rivers. We developed two flood chronologies based on (1) visual identification of “flood-ring” anatomical anomalies and (2) a simple method for quantitative measurements of earlywood vessel width (VW). Using visual flood rings, we have developed a response index (RI) chronology of floods from 1780–2013 and, using the VW measurements, we have developed a quantitative reconstruction of spring river levels from 1800–2013. Both the RI and VW chronologies are strongly related to spring river flooding and indicate that major floods such as those in 1805, 1826, 1844, 1852, 1858, occurred in the period prior to the systematic collection of stage data, and that the frequency of extreme events has greatly varied over the past two centuries. These chronologies provide important new information about Lower Mississippi River flooding in past centuries, and our simple method of measuring VW is a potentially useful new approach to the development of tree-ring records of flooding.

The importance of turtle populations to wetland restoration in the Upper Mississippi Embayment of the Mississippi Alluvial Valley

The Upper Mississippi Embayment (UME) ecoregion covers approximately 141,895 km2 and historically supported 9,712,455 ha of bottomland deciduous forests, swamps, bayous, and rivers. Only about 500 ha (< 0.01%) of pre-settlement bottomland hardwood forest habitat in the Mississippi Alluvial Valley (MAV) in the UME remained by the 1940s because the timber was clearcut and the wetlands drained for agriculture. By 1983 only a few scattered cypress-tupelo swamps remained. We studied the freshwater turtle community in Allred Lake, Missouri, a rare remnant of this ecosystem and compared these results to those from two other study sites in the MAV, Big Oak Tree State Park (BOTSP), Missouri, and Coldwater River National Wildlife Refuge (CRNWR), Mississippi. Species richness included six species commonly found throughout the MAV. One species (Red-eared Slider, Trachemys scripta elegans) dominated density and biomass in all three assemblages. The occurrence of the six species we studied in man-made restored wetlands such as those in BOTSP and CRNWR indicate these turtles would adapt to restored wetlands in the MAV in southeastern Missouri and elsewhere in the ecosystem. We provide information on habitat features that could be included in restoration design and construction that would benefit turtles. Given the ongoing worldwide decline of turtles, consideration of turtle ecology and behavior in wetland restoration projects in the MAV may be warranted.

Red oak acorn yields in green‐tree reservoirs and nonimpounded forests in Mississippi

ABSTRACTAlthough bottomland hardwood forests in southeastern United States are among the most productive ecosystems in North America, indigenous flora, wildlife, and system dynamics have been altered and affected by natural and anthropogenic effects. Historic spatio‐temporal dynamic flooding in hardwood bottomlands caused managers to create green‐tree reservoirs (GTR; i.e., impounded forested tracts) to enhance predictability of seasonal inundation chiefly for waterfowl habitat and hunting. Bottomland red oaks (Quercus spp.) are valuable trees for wildlife that consume acorns they produce. There was inconsistent evidence in the scientific literature, so we tested the null hypotheses of no differences in annual yield, percentage of sound acorns, and proportion of ‘high‐yielding’ red oaks in GTRs and nonimpounded naturally flooded forests (NFF) in western and east‐central Mississippi, USA, during autumn–winter, 2008–2012. Mean annual yields of sound acorns from GTRs and NFFs at Noxubee National Wildlife Refuge and Delta National Forest had overlapping confidence intervals in all years of our study; however, percentages of sound acorns were greater in GTRs in 3 of 8 site‐year comparisons. We also found conflicting results between study sites regarding which flood regime had the greatest proportion of high‐yielding oaks. Our results demonstrate differences in total acorn yield by red oaks may be neither statistically nor biologically different between GTRs and NFFs in Mississippi; however, the proportion of sound acorns may be greater in GTRs relative to NFFs in some years. Future research may determine whether these phenomena are related to surviving trees producing increased seed propagules in response to long‐term flooding stress in GTRs or residual trees possessing traits for increased acorn production in some years. Nonetheless, deleterious effects from persistent or prolonged within‐ and among‐year flooding of GTRs are well‐documented, suggesting managers should consider these possible consequences in sustaining and regenerating lowland red oak populations. © 2019 The Wildlife Society.

Seasonal physiology and growth of planted oaks with implications for bottomland hardwood restoration

Afforestation and reforestation of once dominant bottomland hardwood forests in the southeastern United States can provide ecosystem services and wildlife habitat. However, challenges of prior site conditions, seasonal flooding, soil texture and lack of nearby seed sources can necessitate planting of seedlings to achieve desirable results, particularly for large-seeded species like oaks. Therefore, the objectives of this study were to compare growth and survival of two species of oaks common to southeastern and bottomland hardwood forests, cherrybark oak (Quercus pagoda Raf.) and willow oak (Quercus phellos L.) from 1-0 bareroot, conventional container (0.24 L) and large container (3.8 L) planting stocks across two growing seasons. Additionally, we sought to compare physiology across seedling types to determine the underlying differences in functioning that led to the growth responses. Despite above average rainfall, growth was modest particularly at the site that was previously pasture land and for willow oak which also exhibited net dieback. Two-year survival was adequate (> 75%) for bareroot and large container seedlings but was suboptimal (~ 50%) for conventional container seedlings. Large container seedlings had about 40% higher photosynthetic rates and 70% higher water use efficiencies compared to bareroot and conventional container seedlings. Cherrybark oak exhibited greater stomatal regulation across the growing season than willow oak, however all seedling types displayed increased stomatal conductance and decreased water use efficiency throughout the growing season. Overall, these findings highlight the importance of matching species to site conditions and providing competition control particularly on grassland sites and during above average rainfall conditions.

Water Table Drawdown Alters Soil and Microbial Carbon Pool Size and Isotope Composition in Coastal Freshwater Forested Wetlands

Loss of coastal wetlands is occurring at an increasingly rapid rate due to drainage of these wetlands for alternative land-uses, which also threatens carbon (C) storage in these C-rich ecosystems. Wetland drainage results in water table drawdown and increased peat aeration, which enhances decomposition of previously stabilized peat and changes stable C isotope profiles with soil depth. The effect of water table drawdown on the pool size and δ13C signature of plant C, soil organic C (SOC) and microbial biomass C (MBC) across a range of organic and mineral soils has not previously been reported in coastal freshwater forested wetlands. To this end, litter, roots, and soils were collected from organic and mineral soil horizons in two coastal freshwater forested wetlands in North Carolina with different hydrological regimes: 1) a natural bottomland hardwood forest (natural); and 2) a ditched and drained, intensively-managed wetland for loblolly pine silviculture (managed). We found that hydrology and soil horizon, and to a lesser degree micro-topography, was important in shaping observed differences in size and 13C signature of soil and microbial pools between the natural and managed wetland. The natural wetland had higher SOC and MBC concentrations in the litter, surface organic, and mineral horizons compared to the managed wetland. In the managed wetland, 13C of SOC was enriched across most of the soil profile (Oa and mineral soil horizons) compared to the natural wetland, suggesting enhanced decomposition and incorporation of microbially-derived inputs to soils. Root C concentration decreased with soil depth, while root 13C signature became enriched with soil depth. In the litter and Oe horizon of the natural wetland, MBC was higher and 13C of MBC and SOC was enriched in hummocks compared to hollows. The 13C of MBC and SOC tended to be enriched in upper soil horizons and depleted in lower soil horizons, particularly in the managed wetland. We conclude that drainage of these coastal wetlands has enhanced the breakdown of previously stabilized C and has the potential to alter regional C storage, feedbacks to climate warming, and ecosystem responses to changing environmental conditions.

Wood Biomass and Carbon Pools within a Floodplain Forest of the Congaree River, South Carolina, USA

Riverine forests support high rates of plant productivity, yet total wood carbon (C) stocks in these systems remain understudied. We measured C concentrations and dry mass of live and dead detrital wood to understand their importance relative to total ecosystem C storage across an elevation gradient on the floodplain of the Congaree River. Our study sites included a low elevation bald cypress swamp and three higher elevation mature mixed bottomland hardwood communities. Average wood C concentration was 45.9 ± 0.07% and estimated cumulative C pools (sum of downed and standing dead wood plus live tree, sapling, and shrub wood) ranged from 6850 to 17,200 g C/m2 for bottomland hardwood forests and 17,700 g C/m2 for the bald cypress swamp. Most of the aboveground C was stored in living wood (83.1–90.5% total aboveground pools). Our results indicate that the mass and C stored in live and dead wood are at the high end of both measured and modeled ranges reported in the literature for temperate zone forests. As such, the mature bottomland forests of the Congaree River represent a substantial and important store of sequestered C.

Do forest property characteristics reveal landowners' willingness to accept payments for ecosystem services contracts in southeast Georgia, U.S.?

Previous research has found that the manner in which forests are managed reveals forest owners' goals and management preferences for their properties. In this study, we attempt to predict forest owners' participation in payments for ecosystem services (PES) programs using observable forest management in southeast Georgia, U.S. For this task, we rely on forest property characteristics identified from publicly available aerial images and databases. We examine whether and how forest property characteristics are related to family forest owners' preferences towards PES programs. The results from a random parameter logit model indicate that forest owners in southeast Georgia with planted pine forests, bottomland hardwood forests, or residential structures are more likely to participate in hypothetical PES programs. The results also indicate that forest owners' willingness to accept compensation to participate in PES programs is negatively related to the proportion of planted pine and bottomland hardwood forest areas, and to the existence of a residential structure on one's property. Findings of our study indicate the potential of revealed forest property characteristics in identifying and targeting PES programs.

Assessing Issues in Wildland Habitat Management in the State of Mississippi

In the last several years, the degradation of natural areas has been occurring at an alarming proportion. Open spaces that provide habitats to different life forms are being degraded because of improper management practices, contamination, and the desire to sustain societal needs for housing, transportation etc. In the process, habitat loss stands as one of the most significant threats to biodiversity and a major environmental problem facing society. In the literature, the loss, degradation and alteration of habitats are the primary factors responsible for the global disappearance of rare species of wild animals and plants. While some may assume that habitat destruction and loss of biodiversity are problems of species rich developing nations, it has become a serious problem in the United States (US). In the state of Mississippi, most of the bottomland hardwood forests and significant portions of thousands of acres of wetlands and streams have been degraded because of sedimentation and agricultural runoff fueled by intense farming activities. Notwithstanding previous mitigation measures, there has not been a substantial effort to examine these issues alongside current initiatives in habitat conservation in Mississippi. To fill that void, the paper examines the issues in wildlife habitat conservation as well as current initiatives with emphasis on the trends and factors using mixscale methods built on integrated Geographic Information Systems (GIS) and descriptive statistics. On the one hand, the temporal profile from the results point to changes in the form of gains and declines in the Conservation Reserve Program (CRP) land areas with the Central and Northeast region outpacing the Southwest zones of the state coupled with degradation. On the other, GIS mapping of change, not only showed the concentration of vast natural areas dispersed statewide, but pinpointed clusters of habitats slated for restoration and mitigation. With changes attributed to unsustainable land use practices, policy lapses, limited education and poor monitoring, community efforts remain in high gear among stakeholders to ensure habitat protection. Accordingly, the paper proffered solutions based on the need for conservation, adherence to best management practices, education and support for local participation.

Comparison of Two Crayfish Trapping Methods in Coastal Plain Seasonal Wetlands

AbstractWe compared crayfish collections from minnow versus microhabitat traps in the Dahomey National Wildlife Refuge, Bolivar County, Mississippi, extending the knowledge of microhabitat trap effectiveness to seasonal bottomland hardwood forest floodplains. Crayfishes were captured in three seasonally flooded habitat types: wooded, trail, and open habitats. The CPUE of vernal crayfish Procambarus viaeviridis and White River crayfish P. acutus was higher in minnow traps, whereas the CPUE of swamp dwarf crayfish Cambarellus puer was higher in microhabitat traps. The CPUE did not differ among habitat types for either trap type. In minnow traps, the CPUE of vernal and White River crayfishes increased steadily during the study, whereas the CPUE of swamp dwarf crayfish did not vary over time. In microhabitat traps, the CPUE did not vary over time for any species. Microhabitat traps were more effective at collecting adult, female vernal crayfish in the winter than in spring, whereas minnow traps were more effective at collecting adult, female vernal crayfish in the spring than in winter. Form I males of all three species were collected in both trap types throughout the study, whereas the only ovigerous females collected were swamp dwarf crayfish. Microhabitat traps caught more small crayfishes, pertinent to studies of population structure and recruitment, and were more effective at collecting adult swamp dwarf crayfish, a species five times smaller than other collected species. Conversely, minnow traps provided a better understanding of abundances and population structures of larger crayfishes. Using both trap types provided data on all size‐classes and life stages and reduced sampling selectivity.

Survival and habitat use of sympatric lagomorphs in bottomland hardwood forests

Lagomorphs are important consumers and prey in ecosystems worldwide, but have declined due to land use changes and habitat loss, and such losses may be exacerbated for specialist species. We compared survival and habitat use of two closely related lagomorphs, the swamp rabbit (Sylvilagus aquaticus (Bachman, 1837)), a bottomland hardwood (BLH) forest specialist, and the eastern cottontail (Sylvilagus floridanus (J. A. Allen, 1890)), a habitat generalist. We tested whether survival and habitat use differed between radio-collared swamp rabbits (n = 129) and eastern cottontails (n = 72) monitored during December 2009 – December 2013 in southern Illinois. We found interactive effects of species and season on survival rates: swamp rabbits had higher annual survival (0.37 ± 0.05 (estimate ± SE)) than did cottontails (0.20 ± 0.05), but this difference occurred primarily during the growing season. Swamp rabbits were located closer to watercourses in areas characterized by higher basal area and more mature BLH forest cover compared with eastern cottontails. Our results suggest that BLH forests may be marginal habitat for cottontails and indicate predation as the primary cause of mortality for both species. Swamp rabbits use of early-successional BLH forest suggests that restoration efforts have been successful. However, as specialists, swamp rabbits remain restricted to a narrow band of bottomlands near watercourses and may benefit from improved upland cover that serves as refugia from flooding.

Dietary Composition of Four Common Chiropteran Species in a Bottomland Hardwood Forest

Understanding foraging habits can be important for elucidating the ecology of any species and for designing appropriate conservation strategies. Common methods for determining bat diets, such as morphological examination of fecal material or recovery of prey fragments under feeding roosts, can be biased towards larger prey with harder exoskeletons by underestimating frequency/occurrence of smaller, softer bodied prey items. Our objectives were to determine prey selection for several common chiropteran species of bottomland hardwood forests in east Texas and to evaluate the use of DNA barcoding for dietary studies by comparing dietary composition to prey availability in four species of bats. We amplified the cytochrome coxidase subunit 1 gene from fecal samples collected from 19 bats of four species and identified arthropods by comparison to the Barcode of Life Data System database. We compared frequency of occurrence in fecal samples to frequency in concurrent night-flying insect sampling. We identified nine insect species from three orders consumed by Perimyotis subflavus, nine species from four orders consumed by Lasiurus seminolus, seven species from three orders consumed by Nycticeius humeralis, and 11 species from two orders consumed by Lasiurus borealis. Coleoptera was the most abundant order available by biomass, but beetles were never found in fecal samples from L. seminolus (n = 5) or L. borealis (n = 7) bats. However, Coleoptera comprised a substantial portion of prey identified from P. subflavus (n = 2) and N. humeralis samples (n = 5). Lepidopteran prey items were found in 13 of 19 bat fecal samples across all species but represented < 7% of arthropod biomass. Although dipteran species were a negligible portion (< 1%) of the available biomass, large numbers of dipterans were identified in fecal samples from all species of bats (13 of 19 samples across all species). Lasiurus seminolus and L. borealis may be selecting prey based on digestibility rather than availability; whereas, both N. humeralis and P. subflavus exhibited a more opportunistic approach to foraging. Based on comparison to other studies of bat diets, traditional techniques for analyzing diet from fecal samples are likely underrepresenting soft-bodied arthropods like dipterans.

Survival and Cause-specific Mortality of Adult Female Eastern Wild Turkeys in a Bottomland Hardwood Forest

Meleagris gallopavo (Wild Turkey) population dynamics are greatly influenced by female survival, and high female-survival rates may offset low reproductive rates and maintain stability in populations characterized by low productivity. Additionally, reproduction may incur a cost to annual survival, given the physiological stress associated with breeding, and predation risks associated with incubation and brood-rearing. We used radio-telemetry and known-fate modeling to quantify annual survival and identify mortality causes of 54 adult female Meleagris gallopavo ssp. silvestris (Eastern Wild Turkey) tracked during 2002–2004 and 2007–2010 in a population characterized by low productivity in a bottomland hardwood forest in Louisiana. We detected 31 mortalities in which predation was the leading cause (87%), primarily attributed to Canis latrans (Coyote) and Lynx rufus (Bobcat). We estimated an annual survival rate of 0.58 (95% CI = 0.47–0.68) with no evidence of seasonal variation. This level of survival appeared to be sufficient to offset low productivity; the population was considered healthy and stable during the study period. Annual survival rates of females that incubated a nest were lower than reproductively inactive females, although confidence intervals overlapped considerably. The mechanisms underlying survival differences between reproductive classes were not entirely clear because survival of nesting females did not greatly decrease during incubation and brood-rearing seasons relative to non-nesters as would be expected under the hypothesis of increased predation risk during reproduction periods. Future studies should aim to better elucidate the links between reproduction and survival in Eastern Wild Turkey populations because this information will have important management ramifications in the southeast, where region-wide declines in productivity have been observed.

Avian Habitat Use in a Chronosequence of Bottomland Hardwood Forest-Restoration Sites

Since the 1950s, anthropogenic activity has caused the loss of millions of hectares of bottomland hardwood forest in the Upper Mississippi River Valley, causing population declines in bird populations. Restoration of these forest stands has been ongoing for the past 2 decades. We assessed bird species presence on sites in the Upper Mississippi River Valley to quantify diversity and relate presence to habitat conditions and sites' age since restoration. We observed higher mean diversities at mature bottomland-forest sites during the spring and autumn, but nested ANOVAs indicated no significant differences among restoration-age categories during spring. During the autumn, the 15–23-y and the mature bottomland-forest categories were significantly different from the <7-y category. Predictive habitat models differed among species, but presence of forest-dwelling birds was positively related to forested conditions, such as tree height and tree density. Overall, our analyses show that a variety of birds use these sites, and we suggest further exploration of how assemblages may change in future surveys.

Environmental and landscape factors affecting the continued suppression of canebrakes (Arundinaria gigantea,Poaceae) within restorations of bottomland hardwood forests

Canebrakes in the southeastern United States form a unique ecosystem composed of monotypic stands of the cane species Arundinaria gigantea Michaux within bottomland hardwood forests. Since European settlement, canebrakes have been reduced to less than 2% of their historic range and are considered a critically endangered ecosystem. Despite efforts to restore bottomland hardwood forests to the landscape, current practices have yet to address restoration strategies for canebrakes. This paper synthesizes current understanding of abiotic and biotic factors limiting canebrake reestablishment within bottomland hardwood forest complexes. Consideration is given to the effects of hydrology, landscape and biogeographic factors, disturbance, cane reproductive history, growth patterns, and herbivory on canebrake establishment and persistence. While there is no single factor controlling the distribution and abundance of canebrakes, it is reasonable to believe abiotic factors have a greater impact on the establishment of canebrake systems than biotic factors. Once ecosystem hydrology, topography, and disturbance regimes are restored, biotic factors may have a greater limiting effect on canebrake reestablishment. Herbivory is particularly detrimental to canebrake formation and maintenance by decreasing cane density and cover, selectively removing root stock, and facilitating colonization of areas formerly occupied by cane. This review concludes that under current restoration and management practices of restored bottomland hardwood forests, widespread canebrakes seem unlikely to reestablish.

Passive Restoration of Forest Structure and Composition in Bottomland Hardwood Forests in Texas

Located southwest of Houston, Texas, the Columbia Bottomlands comprise a significant complex of the bottomland hardwood forest ecosystem. As the largest expanse of forest adjacent to the Gulf of Mexico in Texas, the Columbia Bottomlands are critical stopover and staging habitat for Nearctic—Neotropical migratory landbirds. They have been cleared to less than one-quarter of their historical extent of 283,000 ha. Restoration of bottomland forests has predominantly focused on planting just a few heavy-seeded, mast-producing species, such as oaks (Quercus spp.) and hickories (Carya spp.), but such active restorations often fail to meet management objectives of vertical structural complexity, unevenly aged trees, standing dead snags, and coarse woody debris, and do not adequately develop into quality habitat for birds and other wildlife. This study investigates the potential for passive restoration—colonization via natural dispersal—to restore previously cleared areas of bottomland floodplains. Vegetation surveys were conducted in passively restored second-growth forest of varying ages within the Columbia Bottomlands to quantify the structure and composition of vegetation regrowth, and compared to a nearby old-growth stand. At 18–20 y old, the Dance Bayou Site resembled a young forest with open areas of dense vines. At approximately 50–72 y old, the Sweeny Site had characteristics of a mature forest, with vertical structural complexity, unevenly aged trees, standing snags, coarse woody debris, and a greater richness of woody plant species than a nearby old-growth stand. The passively restored sites adequately recruited heavy-seeded species. Passive reforestation has great potential in the Columbia Bottomlands.

Bat community response to silvicultural treatments in bottomland hardwood forests managed for wildlife in the Mississippi Alluvial Valley

Abstract Silvicultural treatments (e.g., selective timber harvests) that are prescribed to promote wildlife habitat are intended to alter the physical structure of forests to achieve conditions deemed beneficial for wildlife. Such treatments have been advocated for management of bottomland hardwood forests on public conservation lands in the Mississippi Alluvial Valley. Although some songbirds respond positively to these management actions, and wildlife-forestry indirectly promotes bat prey availability, bat response is largely unknown. Forest structure may affect bat use of bottomland forests due to differences in foraging space or roost sites. We examined the effects of silvicultural treatments that were implemented to promote wildlife habitat on bat species activity. We conducted vegetation surveys and sampled insect biomass within 64 treated and 64 reference stands located on 15 public conservation areas in Arkansas, Louisiana, and Mississippi, USA. We examined the influence of vegetation metrics and insect biomass on acoustic detections of bats during passive nocturnal surveys in these stands. Detections of bat activity were similar between silviculturally treated stands and reference stands, indicating that both managed and reference stands provide habitat for generalist and forest interior bat species. Generalist bat species (e.g., evening bats, eastern red bats, and Seminole bats) were positively associated with increased insect biomass and the amount of dead wood within a stand. Basal area of large trees was positively associated with detection of tri-colored bats and bottomland specialists (Rafinesque’s big-eared bats and myotine bats). Conversely, acoustic detection of bats was negatively associated with increased vegetative density (i.e., clutter). Managers that implement silvicultural treatments to improve desired forest conditions for wildlife can provide habitat for both generalist and forest interior bat species by providing heterogeneous forest structure that includes dead wood, high basal area of large trees, high tree species diversity, and gaps that are sufficiently thinned to allow unimpeded flight by bats.

Characteristics of a Bottomland Hardwood Forest at Arcadia Lake, Edmond, Oklahoma, with Special Emphasis on Green Ash (Fraxinus pennsylvanica Marshall)

We characterized the structure and tree species composition of bottomland hardwood forest at Arcadia Lake, Oklahoma County, Oklahoma. Additionally, we quantified the age structure of Fraxinus pennsylvanica Marshall (green ash) at the study site in order to establish a baseline dataset in the event that Agrilus planipennis (emerald ash borer) invades F. pennsylvanica stands in central Oklahoma. Three species, Salix nigra Marshall (black willow), F. pennsylvanica , and Populus deltoides W. Bartram ex Marshall (cottonwood) accounted for over 98% of importance values. These three species were also common in the understory. We found that 95% of F. pennsylvanica established following Arcadia Lake reaching pool conservation status in 1987. Arcadia Lake has experienced five sustained flooding events since 1995 that have likely played a role in regeneration at the study site. In particular, we showed that the 1995 event resulted in reduced radial growth in seedlings of F. pennsylvanica . Two biotic stressors appear to be influencing F. pennsylvanica overstory trees, Castor canadensis (American beaver) and Hylesinus spp. (ash bark beetle), which will likely enhance the establishment of A. planipennis at the study site. We recommend expanding the study of Fraxinus spp. forest stands in Oklahoma. Baseline data on Fraxinus species prior to an A. planipennis range expansion to central Oklahoma can enhance strategies for control and management of this invasive insect by identifying the traits of surviving ash following the invasion.

Land use impacts on floodplain water table response to precipitation events

AbstractTwo floodplain sites were instrumented, a bottomland hardwood forest and a historic agricultural field. Continuous, automated, in situ shallow groundwater monitoring was paired with a gridded sampling design to facilitate detailed spatiotemporal analysis of water table response to precipitation events. Data were collected at 30‐min intervals for the duration of the 2011, 2012, 2013, and 2014 water years. Four hundred three precipitation events were observed, with median depth of 3 mm. Results show significantly (p &lt; .001) greater study site median water table response at the agricultural site (0.02 m), relative to the forest (0.01 m). The ratio of water table response magnitude to precipitation depth was 8.3 and 3.3 at the agricultural and forest sites, respectively, a difference of more than 150%. Median shallow groundwater level lag time was shorter with respect to both precipitation and streamflow at the agricultural site (10 and 2 hr for precipitation and flow, respectively), relative to the forest (11.5 and 4.5 hr for precipitation and flow, respectively). Longer lag times indicated slower water table response and potentially increased flood attenuation capacity by the forest site. Results show the agricultural site water table responded to a greater number of precipitation events (including smaller events), reflecting potentially reduced relative flood attenuation capacity. Observed differences highlight the various impacts of forest vegetation on water table dynamics and emphasize the benefits of floodplain forests as a water resource management tool, including for flood mitigation, in mixed‐land‐use watersheds.

Early Stump Sprout Development after Two Levels of Harvest in a Midwestern Bottomland Hardwood Forest

Sprouting is an important source of regeneration for hardwood trees but has not been studied extensively in bottomland hardwood forests. We quantified the sprouting responses of 11 bottomland hardwood species or species groups after two levels of overstory harvest, including clearcutting with reserves (CCR) (residual basal area ∼2.0 m2/ha) and basal area retention (BAR) (residual basal area ∼8.0 m2/ha), in northern Missouri. The probability of sprout presence after one growing season decreased with increasing parent tree dbh for boxelder, river birch, hickories, hackberry, and American elm, as well as for eastern cottonwood and pin oak after three growing seasons. Harvest treatment affected the probability of sprout presence after three growing seasons for silver maple and American elm, with higher probabilities in CCR than BAR. After three growing seasons, height of the dominant sprout per stump was greater in CCR than in BAR across species. The sprouting probabilities and subsequent survival and growth of sprouts suggest that promoting coppice regeneration would favor silver maple, American elm, and American sycamore at the expense of oak species, river birch, and eastern cottonwood.