Hardwood management has been discouraged because of long rotations, low stumpage values, expensive treatments, and an undependable market (Bechtold and Phillips 1983). Knowledge gaps on how various biological factors affect hardwood growth also exist. Stand improvement methods attempt to shift growth to desirable stems. Three different hardwood stand improvement treatments were evaluated. A pre-commercial chemical thin occurred in a twelve year old stand in 1990. In 1995, two of the treatments showed a significant increase in dbh over the control. However, the 2004 measurements of the stand did not find any significant differences between treatments. A case study examined paired plots throughout the state of Virginia where the crown touching crop tree release method was applied. In both the Piedmont and Ridge and Valley regions of the state an increase in dbh was observed. Finally, a timber stand improvement study examined different treatments in a 60-80 year old stand, but did not result in any significant increases in volume after three years. When oaks are harvested or a major disturbance occurs, the number of oaks that regenerates is less than there were previously (Smith 1992). Therefore, oak regeneration is a problem and methods are needed to facilitate oak regeneration (Smith 1992). One method of oak regeneration was examined. Burning five years after a deferment cut did not result in significantly more stems of oak regeneration. Various reductions in basal area also did not result in an increase in oak regeneration under our 60-80 year old timber stand improvement study. These studies attempt to close knowledge gaps in hardwood management and provide useful information for non-industrial private forest (NIPF) landowners. It is so important to target NIPF landowners because the 350 million acres of timberland they own will play a large part in the future of the United States timber supply (Haynes 2002). / Master of Science

Problems developing tall oak seedlings of high abundance have become a concern throughout many eastern hardwood forests. The decline in oak seedling recruitment into canopy positions is often attributed to the increasing abundance of shade tolerant midstory species, especially red maple (Acer rubrum L.). Studies have shown that increasing light to the understory by way of a midstory removal has the ability to favor oak seedlings over competitors. The majority of studies to date have examined northern red (Quercus rubra L.) and cherrybark oak (Quercus pagoda Raf.) on productive sites, but relatively little is known about the effects of midstory removal on white (Quercus alba L.) and black (Quercus velutina L.) oaks, which are valuable species commercially and for wildlife. This study tests the effect of a midstory removal on oak seedlings and red maples six years after treatment implementation. In addition to seedling growth, survival, and competitiveness, the study also illustrates the changes in canopy structure and light transmittance resulting from the midstory removal. Basal clipping response of white oak seedlings following six years under a midstory removal is also examined as a method for regenerating more vigorous oaks. Results from this study support implementation of midstory removal as a method for improving oak regeneration.

In this research, the fire effects on structural and compositional change, and advance regeneration of oak forests in the Ozarks of Missouri were investigated by combining the statistic methods of MANONA, survival analysis, CART analysis, and logistic analysis. Results indicated that fire treatments significantly reduced the midsotry and understory basal area and stem density. However, fire effects on overstory tree survival differentiated among size classes. A new morphological variable, ratio of the total height to the square of basal diameter, was found to be statistically significantly related to the tree mortality rate for most of the species. The developed logistic regression models for selected species using the morphological variable well simulated the impact of initial stem size of advance regeneration on mortality for most of the species. The resultant logistic regression models could be a potential tool to compare and quantify species response to fires on a comparable basis.

This study compared the effects of selective cutting (SC) and the first shelterwood (SW) cut in oak (Quercus)-dominated forests of western Virginia. The specific attributes compared were: (1) tree species composition; (2) seedling, sapling, and overstory tree density; (3) overstory tree quality and size; (4) sapling crown class; and (5) canopy closure. Seedlings, saplings, and overstory trees were sampled at 22 SC and 28 SW sites. Significant differences identified between the two harvest types included: biodiversity of overstory and seedling layers; species densities for seedlings, saplings, and overstory trees; species composition across forest layers; and average canopy closure. Regeneration was poorer on SC than on SW, especially among oak species where SC oak seedling density averaged 5,651 stems ha-1 and SW oak seedling density averaged 9,843 stems ha-1. Selective cutting and SW may both contribute to mesophication of oak-dominated forests in the southern Appalachian Mountains; however, SC resulted in a higher percentage of mesic species post-harvest, and the SW tended to have more oak regeneration. / Master of Science / Selective cutting in the form of high-grading (harvesting only the most valuable trees in a forest) and diameter-limit cutting (harvesting all merchantable trees in a forest above a designated diameter at breast height) is the predominant timber harvest practice in the southern Appalachian Mountains. It is contributing to a shift in forest composition away from oak species toward tree species of lower commercial and wildlife value. In this study, although there were fewer seedlings and saplings after selective cuts than after shelterwoods (a partial harvest of trees aimed at encouraging the regeneration of desirable tree species such as oaks in the future forest), there was higher tree species diversity among the seedlings and saplings at selective cutting sites than at shelterwoods. Oak regeneration remains a challenging goal to meet, but silvicultural systems such as shelterwoods that are designed to promote oak regeneration are likely to be more successful than selective cutting at maintaining oak dominance in this forested region.

The formation of dense understories in eastern forests has created low light environments that hinder the development of advance oak reproduction. Studies have shown that a midstory removal can enhance these light conditions and promote the development of competitive oak seedlings. Previous studies have been primarily focused on oaks found on productive sites, and there is little knowledge of this treatment’s potential on intermediate sites and the typically associated oak species. This study investigates the seven-year effects of midstory removal on natural and underplanted white (Quercus alba L.) and black oak (Quercus velutina L.) reproduction, as well as competing red maples (Acer rubrum L.), on intermediate sites within the western rim of the Cumberland Plateau. In addition to its effect on stand reproduction, this study also investigates the impact of this treatment on microclimate. Results from this study can provide a look at the long term success of midstory removal on intermediate quality sites and serve as a basis for future oak management in the region.

Fire has influenced species composition within the Central Hardwood Forest for millennia. Since the last glacial retreat, Native Americans followed by European settlers used fire as a tool to manipulate their environment. This fire use by humans helped maintain the dominance of well-adapted oak-hickory species across eastern forests. By the 1940's, land fragmentation from increased settlement and actively enforced suppression policies effectively eliminated fire from the landscape. Without the disturbance of recurrent fire that alters succession, the fertile loess-capped hills of southern Illinois have undergone several decades of compositional and structural change manifested by encroachment of mixed mesophytic competitors that are maladapted to fire. Today, land managers seek practical methods to restore declining oak-hickory forests. Southern Illinois forests in particular are lacking information on how cutting and prescribed fire techniques can be applied to encourage regeneration of oak-hickory species. In 2002, five sites were chosen across the Greater Shawnee Hills geographic region for similar ecological characteristics. A factorial combination of thinning and a fire treatment consisting of two burns was used to test the response of understory components including: seedling density, seedling height, seedling diameter, non-tree cover and available sunlight. Results showed a distinct improvement in oak-hickory seedling competitive position as compared to non oak-hickory species. Seedlings of sassafras out-competed all other groups in this study and were the only species to increase in both density and height following repeated fire. The non-tree vegetation layer increased as a result of thin from below treatments, while burning had no effect on the amount of available sunlight. Generally, woody seedlings benefited from thinning based on their physiological adaptations and fire essentially acts as a filter selecting for traits of disturbance-prone vegetation.

Several reports of widespread establishment of mesophytic vegetation within oak-hickory upland forests have been documented throughout the Central Hardwoods Region. Previous studies suggest deviations from historic disturbance regimes may be a primary driver of vegetation change, necessitating the use of Fire Regime Condition Class (FRCC) guidelines to measure changes in forest structure. Current parameters of forest structure and fuel loading were assessed within mature oak-hickory uplands throughout the ecological subsections of the Shawnee National Forest, including the Greater Shawnee Hills, Lesser Shawnee Hills, Cretaceous Hills, and the Illinois Ozarks. Present species importance values and forest structure were compared with reference conditions developed from General Land Office records(Fralish et al. 2002). Current uplands contained an average 214.72 ± 16.52 SE trees/ac and 103.37 ± 2.16 SE ft2 BA/ac, while reference stands harbored less than 90 trees/ac with a range of 16 and 120 ft2 BA/ac. Due to the high levels of fragmentation and a lack of large contiguous upland stands within the Shawnee National Forest, stand level criteria for FRCC values were developed as opposed to landscape level FRCC values which are commonly used. FRCC values determined during initial surveys were compared with plot level ratios of forest structure parameters regarding oaks:mesophytes and xerophytes:mesophytes, yielding clear relationships between species composition and FRCC values. Fuel loading (tons/ac) was assessed as a determinant of FRCC values, however a significant relationship between FRCC values and fuel loading was not discovered. Since widespread deviations from the historic fire regime have taken place since the early 20th century, Fire Regime Condition Class values were found to fall into the FRCC 2 and 3 categories without any stands representing FRCC 1. This determination requires future management practices to follow Fire Regime Condition Class guidelines. The study proved that mesophytic species have become established within all canopy strata, with a strong probability of gaining future dominance without active forest management. Although it is clear that forest structure has deviated from reference conditions, a strong oak-hickory overstory component found throughout the study area provides a potential resource to sustain future oak-hickory upland ecosystems.

White-tailed deer (Odocoileus virginianus) have considerable impacts on woody and herbaceous vegetation. Many oak-hickory forests in the eastern U.S. are experiencing a lack of oak (Quercus) and hickory (Carya) regeneration, with deer being a likely culprit. Furthermore, few have studied deer use of different herbaceous food plot mixtures. I addressed these gaps in the literature by assessing deer impacts on forest and herbaceous vegetation in southern Illinois. I established 150 paired plots (enclosed and control) in June 2015 and measured 25 habitat variables to assess impacts of deer herbivory from August 2015 to August 2016. Oak seedlings were present more often and in higher numbers within enclosed plots (F1,299 = 6.25, P < 0.050 and F1,387 = 4.50, P < 0.050, respectively). There were no differences in the height of oak seedlings or the presence, number, or height of hickory seedlings in enclosed versus control plots (F1,53 = 0.010, P = 0.938; F1,299 = 0.850, P = 0.357; F1,267 = 1.16, P = 0.282; and F1,15 = 0.030, P = 0.855; respectively). During September-November 2015, I counted and marked fallen acorns within 50 random paired plots; the number of acorns discovered or lost did not differ between enclosed and control plots (F1,94 = 0.310, P = 0.578 and F1,8 = 0.120, P = 0.736, respectively). I suggest managers incorporate potential deer impacts when designing management plans to best encourage oak regeneration. During September-November 2015, I established 16 food plots (half tilled; each 0.05 ha in size), planted to 4 food plot types. I compared Big Tine Buck Brunch, Evolved Harvest Throw & Gro, Antler King No Sweat, and a food plot mixture that I created. I measured deer use via 2 methods: vegetation growth in exclosures versus control (i.e., unfenced) areas and camera traps. Deer used all 4 food plot mixtures (n = 292 – 2,522 pictures/plot over 9 weeks), having a negative impact on mean vegetation height outside of exclosures (F3,1148 = 6.71, P < 0.001). Analysis of camera data indicated that deer did not preferentially use any one food plot mixture over the others (F3,12 = 0.090, P > 0.050). There also was no difference in the proportion of deer pictured in the process of eating within each food plot mixture (F3,12 = 0.592, P > 0.050). I suggest any of these 4 food plot varieties could be planted by a hunter or wildlife manager in the Midwest and observe similar use by deer.

Doctor of Philosophy / Department of Horticulture, Forestry, and Recreation Resources / Charles J. Barden / Recurrent, landscape-level fires played an integral part in the development and persistence of eastern oak (Quercus spp.) forests of the United States. These periodic surface fires helped secure a competitive position for oaks in the regeneration pool by maintaining a desirable species composition and forest structure. This historical fire regime was altered with the European settlement of North America, and fire suppression within forestlands became a standard practice since 1930s. With decades of fire suppression, mature oak-dominated woodlands have widely converted to shade-tolerant tree species. Prescribed fire has successfully been used to enhance oak regeneration in eastern forests. However, oak woodland restoration within the forest-prairie ecotone of the Central plains has not been systematically studied. Fuel beds under shade-tolerant species are often less conducive to fire. Therefore, monitoring fuel loading (FL) and its changes are essential to inform management decisions in an oak regeneration project. Rapid expansion of eastern redcedar (Juniperus virginiana/ERC) is another ecological issue faced by land managers throughout North America’s midcontinent forest-prairie ecotone. Hence, it is worthy to monitor ERC expansion and effects on deciduous forests, to inform oak ecosystem restoration interventions within this region. Therefore, the main objectives of this dissertation were three-fold: (1) understand the effects of prescribed burning and mechanical thinning to encourage oak regeneration; (2) investigate the initial effects of an oak regeneration effort with prescribed fire and mechanical thinning on FL; and (3) monitor the spatio-temporal dynamics of ERC expansion in the forest-prairie ecotone of Kansas, and understand its effects on deciduous forests. The first two studies were conducted on a 90-acre oak dominated woodland, north of Manhattan, Kansas. The experimental design was a 2 (burn) x 2 (thin) factorial in a repeated measures design. The design structure allowed four treatment combinations: burn only (B), thin only (T), burn and thin combined (BT), and a control (C). Burning and thinning treatments were administered in spring 2015. Changes in the FL estimates after the burn treatment revealed that the BT treatment combination consumed more fuel and burned more intensely compared to the B treatment. This observation was reflected in vegetation responses. The thinning reduced the canopy cover significantly, but under enhanced light environments, both oaks and competitive species thrived when no burn was incorporated. In contrast, burn treatments controlled the competitive vegetation. Hence, the most promising results were obtained when both fire and thinning were utilized. The remote sensing study documented the expansion of ERC in three areas of eastern Kansas over 30 years. The use of multi-seasonal layer-stacks with a Support Vector Machines (SVM) supervised classification was found to be the most effective approach to map ERC distribution. Total ERC cover increased by more than 6000 acres in all three study areas investigated in this study between 1986 and 2017. Much of the ERC expansion was into deciduous woodlands. Therefore, ERC control measures should be incorporated into oak woodland restoration efforts within the forest-prairie ecotone of Kansas.

Problems with oak regeneration, and concerns by environmental and conservation organizations, are driving interest in longer rotations and in reproduction methods that retain the overstory for an extended time period. Clearcutting and shelterwood regeneration methods are providing mixed results for oak seedling development and recruitment due to the increased abundance of shade tolerant midstory species. The irregular group shelterwood (Femelschlag) system has been used in Central Europe to address these issues, and may provide the basis for a gap-based system in the Central Hardwood Forest Region. This study examines the two-year effects of a gap-based regeneration method featuring 60m diameter gaps (0.72 ac), and associated midstory removal 30m into the surrounding forest matrix, on natural oak and competitor tree species reproduction as well as on planted white oak seedlings (Quercus alba L.). In addition to seedling growth and survival, the study also characterizes the spatial patterning of light transmittance from gap centers into the forest matrix beyond gap margins. Results from this study can serve as a basis for oak management addressing recruitment issues and providing a regeneration method compatible with a range of forest ownership objectives.