Master of Science, The Ohio State University, 2020, Environment and Natural Resources

Many Quercus-Carya forests in the eastern United States are experiencing compositional shifts due to the failure of the overstory species to regenerate, while mesophytic species, i.e., Acer rubrum, Acer saccharum, and Fagus grandifolia, increasingly dominate their regeneration layers. The Wayne National Forest (WNF) of southeastern Ohio is largely Quercus-Carya forest ecosystem types, although the sapling regeneration is often dominated by the aforementioned mesophytic species. Through the 2018 resampling of 98 permanent plots established on the Marietta Unit of the WNF in 1993, this research investigates changes in sapling species composition and abundance. Statistically significant changes were observed in seven of the species in the total sapling layer: Acer rubrum, Acer saccharum, Aesculus flava, Carya glabra, Cornus florida, Fagus grandifolia, and Hamamelis virginiana. Within the subcategory of small saplings (stems 0.1-5.0 cm DBH), the ten species that had statistically significant changes were Acer rubrum, Acer saccharum, Carpinus caroliniana, Carya glabra, Cornus florida, Fagus grandifolia, Hamamelis virginiana, Nyssa sylvatica, Prunus serotina, and Ulmus rubra. In the subcategory of large saplings (stems 5.0-10.0 cm DBH), there were two species that had statistically significant changes: Cornus florida and Fagus grandifolia. Overall, the mesophytic species Acer rubrum, Acer saccharum, and Fagus grandifolia continue to dominate the sapling layers of the sampled forests. Fagus grandifolia had significant differences in total saplings, as well as both small and large sapling subcategories. In all three classes, Fagus grandifolia increased in stems per hectare and relative density. In the total sapling and small sapling categories, Fagus grandifolia became the most abundant species. Acer rubrum and Acer saccharum had statistically significant changes in total and small sapling categories, where the stems per hectare and relative densities of both species decre (open full item for complete abstract)

Committee: David Hix PhD (Advisor) Subjects: Ecology; Forestry; Natural Resource Management

Master of Science, University of Toledo, 2014, Biology (Ecology)

During the autumn months in temperate deciduous forests, freshly senesced tree leaves transfer large amounts of labile carbon (C) to the forest floor. Microorganisms readily take up and metabolize labile soluble C (LSC), which defines the initial stage of leaf litter decomposition. As LSC disappears, extracellular enzymes are required to break down insoluble cellulose and hemicellulose for microbial C acquisition. A large pulse of carbon dioxide (CO2) is released when microbes consume litter LSC. Rainfall can increase LSC availability to soil microbes and accelerate the C flux by transferring LSC to the soil. In addition, initial decomposition is highly temperature sensitive and there could be a threshold where C mineralization rates rapidly increases if temperatures exceed 10 °C. However, it is unclear if the 10 °C temperature threshold exists during initial decomposition when LSC concentrations are high. Additionally, it is not well-understood weather the temperature sensitivity during initial decomposition is due to intracellular metabolism or extracellular polymer breakdown. To better understand the temperature response of intracellular metabolism and extracellular polymer breakdown, we incubated sandy soils from 4-20 °C with either 1 cm2 Acer rubrum (red maple) leaf litter pieces or leaf litter leachate for 14 days. We measured daily C mineralization rates, C acquiring enzyme activities, and LSC, labile nitrogen, and phosphate concentrations at four time points. We found that extracellular polymer degradation was more temperature sensitive than intracellular metabolism because enzyme activities in LSC increased as temperature decreased, especially when temperature dropped below 10 °C, and higher enzyme activity resulted in a higher percent of mineralized C. In the litter pieces enzyme activity increased as temperature increased, especially when temperature crossed above 12 °C, which caused higher C mineralization at higher temperatures while LSC from samples be (open full item for complete abstract)

Committee: Michael Weintraub (Advisor); Moorhead Daryl (Committee Member); Chen Jiquan (Committee Member) Subjects: Ecology; Environmental Science; Soil Sciences

Master of Science (MS), Ohio University, 2014, Plant Biology (Arts and Sciences)

The Ohio River Valley is heavily impacted by acid rain, which can profoundly alter soil chemistry by lowering soil pH and phosphorus (P) availability. The species composition in regional forests has been shifting to favor Acer rubrum (red maple) from Quercus spp. (oaks). Acer rubrum has the ability to change sex expression, which may contribute, in part, to this shift. This research investigated whether acid rain could be contributing to the increase in A. rubrum populations by utilizing forest stand-level experimental plots established in 2009. These plots were fertilized to approximate soil P levels prior to acid rain by raising pH and P levels in a complete block design (n=9), with the Control representing current conditions of soil impacted by acid rain. Acer rubrum individuals on these plots were observed and classified as non-reproductive, non seed-bearing or seed-bearing. Seeds from each plot were collected and planted for a germination study and a growth study. Acer rubrum growing in the Control plots were more likely to produce seeds, and produce more seeds per tree. The seeds produced by trees on the Control plots had both higher germination rates and higher seedling growth rates than those from the treatments. In tandem, these findings enhance each other's effects on A. rubrum fecundity, and support the hypothesis that the effects acid rain has on soil is contributing to the increase in A. rubrum populations.

Committee: Jared DeForest (Advisor) Subjects: Plant Biology

Master of Science (MS), Wright State University, 2011, Biological Sciences

My study was conducted to understand tree community structure and how soil moisture and fire frequency influence them. Eighteen plots were placed in the Edge of Appalachia Nature Preserve of unglaciated southern Ohio: nine within a prescribed burn site and nine control sites outside the burn. Sites were stratified in triplicate across GIS-derived integrated soil moisture index (IMI) classes. Burning was done in 1996. Overstory species dbh and sapling species were sampled 1997, 2001, and 2008. Overstory stems were located in 2009 using range finders. Stem locations were loaded into GIS using novel techniques to quantify individual stem IMI values. Nonmetric multi-dimensional scaling identified greater heterogeneity among intermediate and mesic sites than xeric sites. Multi-response permutation procedures did not detect community differences between burned and unburned sites, but did detect strong (A=0.3 to 0.2, T=-3.6 to -4.1) distinct community differences that were statistically significant (P < 0.05) among xeric, intermediate, and mesic IMI classes. Analysis of variance identified significant initial effects of burning on Carya saplings and overstory Sassafras albidum stems, as well as lasting effects significant on Carpinus caroliniana. ANOVA detected significant differences across all sampling years in sapling relative number for Acer rubrum, Sassafras albidum, and Carpinus caroliniana saplings, as well as Quercus prinus, and Liriodendron tulipifera overstory stems between IMI classes. Bonferroni adjusted Kolmogorov-Smirnov tests were used to identify and quantify IMI habitat restrictions of species. Quercus prinus dominated xeric sites (IMI quartiles 18-24), Carya occupied intermediate sites (IMI quartiles 22-44), Acer saccharum occupied intermediate to mesic sites (IMI quartiles 33-44), Sassafras albidum (IMI quartiles 20-40, IMI median 43) and Liriodendron tulipifera (IMI quartiles 39-45) were restricted to mesic sites. My r (open full item for complete abstract)

Committee: James Runkle PhD (Advisor); James Amon PhD (Committee Member); Thomas Rooney PhD (Committee Member) Subjects: Ecology

Doctor of Philosophy, The Ohio State University, 2010, Horticulture and Crop Science

A liner refers to a small plant that is transplanted and grown to become larger. Tree liners are typically produced in the Pacific Northwest of the United States. Even though the Midwestern US has a shorter growing season, many advantages of producing tree liners in retractable roof greenhouses (RRG) in the US Midwest have been previously found. A production system at The Ohio State University (OSU), Columbus, Ohio, using a RRG (Cravo Equipment, Ltd., Bradford, ON, Canada) and containerized tree liner production with or without out planting to pot in pot (PIP) was evaluated in this dissertation. Bottom heat (BH) mats (Olson Products Inc., Medina, Ohio) used for Fall 2007 plantings at 40°F did not affect the growth of trees when compared to plants at ambient temperature (AT). BH treatment for Fall 2008 plantings at 70°F used during winter promoted the height and caliper of red maple (Acer rubrum L. ‘October Glory'®) and Avondale red bud (Cercis chinensis L. ‘Avondale'). Avondale redbud continued to show benefits of BH even 20 months after application in the RRG. Littleleaf linden (Tilia cordata Mill. ‘Greenspine'®) had a better growth in AT than BH. Red maples and littleleaf linden, planted in Fall, showed larger heights and calipers than those planted in Summer due to better acclimation. Fertilizer treatments were used on the first year with either a top dressing of controlled release fertilizer 40g of 19N-2.2P-6.6K (19-5-8, Osmocote Pro with minors, 8-9 months, Scott's Co.), or a top dressing of 20g of CR supplemented with liquid fertilizer (LF), 400 ppm of 21N-3.1P-5.9K (21-7-7, Scott's Company, Marysville, Ohio), via a fertilizer injector (Dosatron®, Clearwater, Florida) once every two weeks (CR+LF treatment). Fall 2007 plantings with CR+LF produced larger caliper for red maple and taller Avondale redbuds. Littleleaf lindens were not affected by the fertilizer treatments in Fall 2007. Summer 2008 plantings had bigger height and caliper with CR for red maple and (open full item for complete abstract)

Committee: Hannah Mathers PhD (Advisor); Daniel K. Struve PhD (Committee Member); Robert C. Hansen PhD (Committee Member); Rebecca S. Lamb PhD (Committee Member) Subjects: Horticulture

Master of Arts (MA), Ohio University, 2006, Geological Sciences (Arts and Sciences)

A remote sensing investigation was conducted in June 2000 in a mixed-oak forest undergoing successional changes at Black Rock Forest, NY. Leaf litter data was collected throughout the fall of 2000 to assess productivity at the site and to obtain species-specific leaf area(LAI SPP) data for Acer rubrum, Quercus prinus, and Quercus rubrum. There were two objectives in this investigation: to determine (1) whether spectral differences exist at branch-level between the oak and maple groups at this site, and (2) whether the remotely-sensed canopy-level classifications are able to produce estimates of canopy cover for red maple that reflect the forest composition identified with the LAI SPPinformation. Significant multispectral differences were identified for all groups at the branch-level. Canopy-level analyses were restricted to the 550 nm wavelength because of calibration issues with the imaging system. These images were processed using soft classification methods, and produced canopy cover maps of questionable accuracy.

Committee: James Lein (Advisor) Subjects:

Doctor of Philosophy, Case Western Reserve University, 2012, Biology

Most pryrogenic ecosystems are endangered due to encroachment of fire-sensitive species and loss of fire-tolerant species caused by altered fire regimes, especially fire suppression. Restoration of these degraded systems typically involves the reintroduction of fire via prescribed burning. I evaluated the efficacy of prescribed fire in reducing woody plant encroachment in fire-suppressed oak-dominated ecosystems in the Bluegrass Region of southern Ohio. In the first study, I tested the effects of biennial fire and a fire surrogate (clipping) on woody and herbaceous vegetation abundance in oak barrens. I found that fire and clipping produce similar responses in vegetation, and although these treatments reduce the aerial cover of shrubs, they do not lessen shrub resprouting or promote herbaceous plants. Next, I described the characteristics of oak-dominated forests prior to the reintroduction of fire. My snapshot of seedling layer vegetation in these forests highlights the variation in vegetation and environmental factors over small and large spatial scales. Despite their distinctions in composition, the structural patterns at all the forest stands provide evidence for a general shift in composition from oak (Quercus) to maple (Acer) dominance. Oaks are failing to regenerate and are being replaced by actively recruiting maples. Fires are predicted to reverse this shift by acting as a filter for maples resulting in the promotion oaks. In my final study, I tested this prediction and evaluated the effects of fire season and topkill with and without heating on forest seedling composition and abundance. I found no clear effect of fire season, or heating, and only limited support for the prediction that fires act as a filter for maples. Overall, these results indicate that fire might maintain initial vegetation conditions, but is not effective in reversing encroachment in oak-dominated ecosystems. Despite the limited spatial and temporal scale of my studies, these results a (open full item for complete abstract)

Committee: Joseph Koonce PhD (Advisor); Roy Ritzman PhD (Committee Chair); Robin Snyder PhD (Committee Member); David Burke PhD (Committee Member); Michael Benard PhD (Committee Member); Matthew Dickinson PhD (Committee Member) Subjects: Biology; Ecology; Forestry

Master of Science (MS), Wright State University, 2012, Biological Sciences

Garlic mustard (Alliaria petiolata) has been previously found to be significantly affected negatively by powdery mildew (Erysiphe cruciferarum). While we could not significantly corroborate those findings we did find evidence that E. cruciferarum does inhibit A. petiolata's allelopathic and competitive effects which benefits some target neighbor species such as Impatiens capensis and Elymus canadensis. We also found that the inhibition of A. petiolata by E. cruciferarum had negative consequences on another neighboring invasive species (Lonicera maackii) compared to those grown next to uninfected A. petiolata. Acer saccharum, a slow-growing species had no effect between neighbors. Sterilization treatments had variable effects on target plants, many of which mirror the effects which allelopathic plants (A. petiolata) that disrupt soil microbes seem to have. Sterilization inhibited growth of E. canadensis through the destruction of beneficial effects from microbes, while increasing the growth of L. maackii by inhibiting the pathogenic effects of microbes.

Committee: Don Cipollini Ph.D. (Advisor); James Amon Ph.D. (Committee Member); Thomas Rooney Ph.D. (Committee Member) Subjects: Biology; Botany; Conservation; Ecology; Environmental Management; Forestry; Plant Biology; Plant Pathology; Plant Propagation; Plant Sciences; Wildlife Conservation

Master of Science (MS), Ohio University, 2012, Environmental and Plant Biology (Arts and Sciences)

Documenting change in the composition and structure of forest communities is important for understanding the distribution and abundances of natural resources, carbon pools, and species. Here, results are presented from the second sampling effort at Dysart Woods, an old-growth, mixed-mesophytic remnant tract in southeastern Ohio. In 2011, trees, saplings, shrubs, herbs, and soils were sampled in permanent plots established in 1996, allowing a direct fifteen–year comparison. Mortality and recruitment rates revealed that while most species at Dysart Woods are decreasing in abundance, sugar maple and American beech are rapidly increasing in importance, as is the invasive Alliaria petiolata. This shift in composition may be due to beech and sugar maple showing little negative responses to neighbors, and/or reflect increasing pressures that old-growth forests face from invasives. Such findings have considerable implications for the future of Dysart Woods, and developing appropriate management techniques may be required to preserve its integrity.

Committee: Brian McCarthy PhD (Advisor); Glenn Matlack PhD (Committee Member); Jared DeForest PhD (Committee Member) Subjects: Botany; Ecology; Forestry