Browse rates of planted oak on a reclaimed mine
Matthew Aldrovandi and Jennifer Franklin
Master’s Student and Research Specialist II (MA) and Professor (JF), Department of Forestry, Wildlife, and Fisheries, The University of Tennessee
Horseshoe Mountain, a former mine site reclaimed in the 1990s, located in Claiborne County, Tennessee was planted in the late fall and winter of 2014 with white oak (Quercus alba), northern red oak (Quercus rubra), southern red oak (Quercus falcata), pin oak (Quercus palustris), and chinkapin oak (Quercus muehlenbergii). Prior to tree planting, soil compaction was relieved and then four different ground cover treatments (wildlife promoting, unpalatable to wildlife, herbicided, and control) were applied over three replicates (12 macroplots total; an area of about 23 acres). Sixty permanent FIA-style plots (24’ radius) were installed in summer 2015 within the macroplots; all trees within the plots were measured for height, root collar diameter, vigor, and browse. Subsequent measurements were recorded twice a year until 2017; vegetation surveys were conducted on the same schedule. The probability of browse was found to be statistically significant in relation to the height of oaks in 2015. In the height class from 0-30cm, 30% of 91 oaks were browsed; in the 31-60cm height class 29% of 253 oaks were browsed; in the 60.5-90cm height class 52% of 218 oaks were browsed; in the 90.5-120cm height class 52% of 23 oaks were browsed. When broken down by species, it was found that 40% of 113 Q. muehlenbergii, 38% of 269 Q. rubra, 38% of 113 Q. palustris, 48% of 25 Q. falcata, and 37%of 65 Q. alba were browsed.
Species-specific mechanisms contributing to the mesophication of upland oak stands in the absence of fire
Emily K. Babl, Heather D. Alexander, Courtney M. Siegert, John L. Willis, and Andrew I. Berry
Master’s student (EKB) and Assistant Professors (HDA, CMS, and JLW), College of Forest Resources, Mississippi State University; Forest Manager (AIB), Bernheim Arboretum and Research Forest
Upland oak forests of the eastern United States are shifting dominance towards shade-tolerant, fire-intolerant species. This shift is hypothesized to lead to mesophication, a process where shade-tolerant, fire-sensitive species (i.e. mesophytes) create a cool, moist understory, reducing fuel flammability and promoting their own proliferation at the expense of pyrophytic, shade intolerant species such as oaks. There have been few empirical studies identifying mechanisms of mesophication, and these studies have yet to extensively explore potential mesophytes other than red maple (Acer rubrum). To address this issue, we sampled four hypothesized mesophytes (A. rubrum, A. saccharum, Carya glabra, and Fagus grandifolia) and two upland oak species (Quercus alba and Q. montana) across a gradient of dbh sizes (20-60 cm) in western Kentucky. We quantified canopy, bark, and leaf litter traits that may lead to differences in forest floor flammability among upland oaks and mesophytes. Preliminary results show that mesophytes have thinner and smoother bark than upland oaks and an increased canopy volume to stem volume ratio, which could decrease forest floor flammability. Initial results from a decomposition bag study indicate that maple leaf litter has 37% mass loss after six months, with 32%, 22%, and 14% mass loss occurring in hickory, oak, and American beech litter, respectively. Delineating the potential mechanisms by which mesophytes could alter forest flammability through their bark, canopy, and leaf litter traits is essential for understanding community stability, and exploring options to successfully manage for conservation of upland oak forests before restoration is prohibitively expensive.
Mixed-severity wildfire promotes oak recruitment and species richness on the Cumberland Plateau, Kentucky
Devin E. Black, Zachary W. Poynter, Mary A. Arthur, Claudia A. Cotton, David D. Taylor, and Beth A. Blankenship
Forestry Technician (DEB), Professor (MAA), and Ecologist (BAB), Department of Forestry and Natural Resources, University of Kentucky; Restoration Supervisor (ZWP), Eco Logic LLC; Forest Soil Scientist (CAC) and Forest Botanist (DDT), Daniel Boone National Forest, USDA Forest Service
Wildland fires of natural and anthropogenic origin were once more prevalent in the oak-dominated forests of the Appalachian Region than they are today. In the absence of periodic fire, forest structure and species composition have shifted within many Appalachian forests. In response, forest managers use prescribed fire to create diversified habitats, restore open stand structure, and enhance the recruitment of desired species, with varied success. As an indirect management tool, mixed-severity wildfire remains largely unstudied, yet may effectively promote targeted species and structural changes in forests. A wildfire within an upland oak forest in eastern Kentucky provided a rare chance to assess forest recovery across a gradient of fire severity. Six years following the wildfire, we found greater net recruitment of oaks and pines on moderate and high fire severity sites compared to low severity; recruitment of mesophytic competitor species was unaffected by fire severity. Additionally, relative stem density of oak and pine saplings and species richness of non-woody plants were positively associated with fire severity. This study illustrates the potential for wildfire to create a mosaic of habitats across a burned area, and elucidates the effectiveness of moderate to high severity fire to benefit oak and pine sapling recruitment in the short term. Though not desirable due to complications for control, human safety, and property protection, this wildfire illustrates the ecologically beneficial effects of mixed-severity fire, inadvertently accomplishing management objectives focused on creating a mosaic of habitats with varied openness and species diversity, elusive outcomes using prescribed fire alone.
Cultural resources plantings of white oak for Cherokee basketry
Brenna R. Bohn, Sunshine L. Brosi, Bryan W. Whitmore, Ami Sharp, Scott E. Schlarbaum
Undergraduate Student (BRB), Associate Professor (SLB), and Former Masters Student (BWW), Department of Biology, Frostburg State University; Research Associate (AS) and Professor and Director (SES), Tree Improvement Program, Department of Forestry, Wildlife, and Fisheries, The University of Tennessee
White oak trees (Quercus alba) are declining in the eastern forests due to high rates of mesophyte invasion due to fire suppression and overpopulation of deer. White oak is vitally important in the southern Appalachians for wood products, food for wildlife, and as a cultural resource for Cherokee basket making. Artificial regeneration for white oak have been challenging and from a Cherokee cultural perspective, another challenge is to produce certain wood properties important to artisans for basket making. These properties are usually found in slow growing white oaks present in the forest understory. We evaluated an 11-year old white oak progeny test, planted on the Qualla Boundary in North Carolina using a variety of tree shelter sizes to increase apical dominance and limit branching. Overall survival was 65.6% and was significantly impacted by initial seedling height (p = 0.045) and number of first-order lateral roots (p < 0.001). The tallest 3 m shelter had the lowest survival (47%). While the 2.3 m shelter experienced 55% survival, 1.8 m shelter 76%, and the 1.5 m shelters with the highest seedling survival of 81%. Survival across open-pollinated half-sibling genetic families lines ranged from 31% to 81% (p = 0.008). Average height was 5.4m (max 9.3m) and the average RCD was 10.7 cm (max 22.3 cm). Cherokee basket makers determined most of the white oaks were too fast growing to be desirable for baskets. Additional plantings on more xeric sites at various densities may assist providing the cultural resources needs for the Cherokee.
TreeSnap: a citizen science tool to help our forests
Bradford J. Condon, Ellen V. Crocker, Abdullah Almsaeed, Albert G. Abbott, C. Dana Nelson, and Margaret Staton
Postdoctoral Scholar (BJC), Research Associate and Web Developer (AA), and Assistant Professor (MS), Department of Entomology and Plant Pathology, The University of Tennessee; Postdoctoral Scholar (EVC) and Project lead (AGA), Forest Health Research and Education Center, Department of Forestry and Natural Resources, University of Kentucky; Research Geneticist and Project Leader (CDN), Southern Research Station, USDA Forest Service
We created TreeSnap, a mobile app available for iOS and Android that connects interested citizens with tree breeding programs to help fight forest threats through both awareness and research. TreeSnap integrates the outreach and education efforts of different tree breeding groups. The mobile app combines reporting for multiple tree species in a single place with an intuitive and convenient interface, while the web database provides an easy way for scientists to analyze the collected data. Our goal is that scientists will gain data on trees to use in research programs while the public will become more engaged in and informed about forest health. Currently, restoration tree breeding programs each have their own portals and requirements for submitting potential trees for inclusion in breeding programs. TreeSnap provides a more unified gateway for members of the public to submit information to scientists. The app is designed to easily incorporate more trees as we build new collaborations. Similarly, each tree submission type is customizable, which allows us to ask different questions for each tree, providing the relevant information to scientific partners. TreeSnap prompts users to take photos of trees and answer questions specified by each tree-breeding program while collecting GPS coordinates. Meanwhile, the web app allows participants to view, track, and edit their submissions, and will serve as a learning resource. For scientists, the web app provides a single location for tracking and curating submissions, contacting participants with questions, and working collaboratively to visit and sample trees of interest.
Delphi expert opinion survey to assess threats to oaks in the eastern United States
Ellen V. Crocker, Anna O. Conrad, Xiaoshu Li, Billy Thomas, Thomas Ochuodho, and C. Dana Nelson
Postdoctoral Scholars (EVC, AOC, XL), Forest Health Research and Education Center, Department of Forestry and Natural Resources, University of Kentucky; Extension Forester (BT) and Assistant Professor (TO), Department of Forestry and Natural Resources, University of Kentucky; Research Geneticist and Project Leader (CDN), Southern Research Station, USDA Forest Service
Oaks are important fixtures of many eastern United States forests, providing both ecological and economic benefits. While regeneration is a major issue impacting oaks currently, biotic (e.g. pests and pathogens) and abiotic (e.g. abnormal weather and climate change) stressors, may also threaten oaks in this region. The goal of our Delphi expert opinion survey is to identify the most significant threats (biotic and abiotic) to oaks in the eastern United States (as defined by the eastern and southern regions of the U.S. Forest Service), and to gauge the potential impact of these threats on oaks. To accomplish this, we initiated a three-part Delphi expert opinion survey. The iterative Delphi approach is useful for evaluating consensus (or lack thereof) among experts on a specific topic. In the course of this survey series, we asked experts to identify current and future biotic and abiotic threats to oaks, and then based on expert opinions, gauged the current and potential impact of these threats by asking a series of questions concerning, for example, their spatial and temporal manifestation. Data collected as part of this Delphi survey series will be used to support subsequent analyses aimed at assessing the economic impact of these threats, and may be useful for prioritizing the management of these threats within the eastern United States.
Survival, cause-specific mortality, and spatial ecology of white-tailed deer in the North Georgia Mountains
Gino J. D’Angelo, Adam C. Edge, Cheyenne J. Yates, Andrew R. Little, Charlie H. Killmaster, Kristina L. Johannsen, David A. Osborn, and Karl V. Miller
Assistant Professor (GJD), Graduate Research Assistants (ACE and CJY), Senior Research Associate (ARL), Wildlife Research Coordinator (DAO), and Wheatley Distinguished Professor (KVM), Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia; State Deer Biologist (CHK) and Program Operations Manager (KLJ), Game Management Section, Wildlife Resources Division, Georgia Department of Natural Resources
Acorn abundance in the Southern Appalachians has been shown to be an important driver of white-tailed deer (Odocoileus virginianus) populations. Reductions in timber harvests on National Forests in recent years has resulted in increased coverage of mature forests and little early successional habitat. The Georgia Department of Natural Resources (DNR) documented an 85% decline in the harvest of male white-tailed deer from 1979-2015 on 8 Wildlife Management Areas (WMAs) in the North Georgia Mountains. DNR substantially reduced harvest of female deer, but populations continued to decline. As densities decreased, the condition of deer improved, suggesting that habitat conditions have not caused declines in fecundity. Therefore, factors other than acorn availability may be driving declines in these populations. Simultaneously, predator populations increased in northern Georgia, including black bears (Ursus americanus) and coyotes (Canis latrans). Therefore, insufficient recruitment of fawns due to predation is suspected as a reason for population declines. In January 2018, we are initiating a study in the North Georgia Mountains to investigate: (1) survival and cause-specific mortality of deer fawns, (2) home ranges and habitat selection of deer, and (3) influence of mast on space-use by deer. We will GPS-collar 30 adult does per year for 3 years on WMAs, and capture and radio-collar their fawns. We will investigate habitat selection and cause-specific mortality of adults and neonates. By identifying habitats most utilized by deer, especially where fawn survival is greater, we hope to provide recommendations for managing habitats and deer populations to reverse population declines.
Twenty-Five years of oak-mast surveys and Allegheny woodrat populations in western Maryland
Erica Duda, Sunshine L. Brosi, A.J. Dayton, Dan J. Feller, and Rande Brown
Master’s Student (ED), Associate Professor (SLB), and Undergraduate Student (AJD), Department of Biology, Frostburg State University; Western Region Ecologist (DJF) and Wildlife Biologist (RB), Wildlife & Heritage Program, Maryland Department of Natural Resources
Allegheny woodrats, Neotoma magister, occur on rocky outcrops, cliffs, and caves in oak-dominated forests where they play an important role dispersing fruits and nuts and altering vegetation. The decline of the Allegheny woodrat corresponds with the loss of the Castanea dentata and currently acorns, Quercus, are their most important food source. Since 1991, acorn production and three extant woodrat populations have been monitored in Western Maryland in the Appalachian Plateau, Eastern Ridge & Valley, and Blue Ridge physiographic regions. Mean number of acorns per branch were recorded from the same ten trees of each section Lepidobalanus and Erythrobalanus at multiple sites within each region. Woodrat populations were monitored using two consecutive night mark-recapture techniques. On the Appalachian Plateau, bumper crop years of black oak acorns were followed by an increase in woodrat captures 75% of the time. Mast failures were followed by sharp declines in woodrat captures 100% of the time. In the Eastern Ridge and Valley there have been no bumper crop years and limited fair-good years for white oak as well as sharp declines in woodrat captures. In the Blue Ridge, there have been limited bumper mast events of white oak, but fair-good years were followed by an increase in woodrats captures 100% of the time (r = 0.575, p = 0.05). Additional factors influencing the woodrat could include habitat fragmentation, gypsy moth, and raccoon roundworm. Allegheny woodrat population viability may improve with supplemental planting of species from the white oak and the black oak group in addition to mast species less impacted by gypsy moth.
Twenty-Five year effects of cutting and prescirbed fire on northern red oak regeneration in Michigan oak and pine stands
Joshua J. Granger, David S. Buckley, Terry L. Sharik, John M. Zobel, William W. DeBord, Jason P. Hartman, Jason G. Henning, Tara L. Keyser, and Jordan M. Marshall
Postdoctoral Research Associate (JJG), Professor (DSB), and Assistant Professor (JMZ), Department of Forestry, Wildlife and Fisheries, The University of Tennessee; Dean (TLS), School of Forest Resources and Environmental Science, Michigan Technological University; Surface Mining Reclamation Specialist (WWD), USDI Office of Surface Mining; State Silviculturist (JPH), Michigan Department of Natural Resources; Research Urban Forester (JGH), Davey Tree Expert Company; Research Forester (TLK), Southern Research Station, USDA Forest Service; Associate Professor (JMM) Indiana University-Purdue University Fort Wayne
Reviews of likely causes of the oak regeneration problem in the 1980s and 1990s stimulated several studies designed to test different methods of reducing competition between oaks and other hardwoods. A study involving multiple overstory and understory treatments was established in 1991 in Michigan oak stands and red pine plantations to test the hypotheses that 1) northern red oak regeneration would be more successful in pine than oak stands and 2) removal of competitors would enhance northern red oak seedling growth and survival. Late spring prescribed fires were implemented on all plots in 2002 and 2008 to investigate their effectiveness in controlling understory red maple. Planted northern red oak performance and natural regeneration of oak and red maple have been documented since 1991. A subset of planted seedlings has been protected against deer browsing since planting. Results suggest partial removal of competitors enhances oak seedling performance, whereas complete removal greatly increases mortality from browsing and frost. Prescribed fire appeared to be ineffective as red maple abundance increased and oak abundance decreased after burning. Greater growth and survival of planted oaks occurred in the pine stands, provided they were protected from browsing. Based on these results, the most viable technique for regenerating oak in the study region would include protecting oak seedlings from deer in 25% canopy cover shelterwoods in pine plantations. Opportunities exist for developing systems involving alternating rotations and mixtures of oak and pine species.
Dendroecological analysis of continued Quercus dominance on edaphically extreme southeastern slopes of the Allegheny Front
Karen J. Heeter and Sunshine L. Brosi
Master’s Candidate (KJH) and Associate Professor (SLB), Department of Biology, Frostburg State University
The Allegheny Front escarpment forms the boundary between the Ridge-and-Valley to the east and the Allegheny Plateau to the west. Peaks including Mount Porte Crayon in West Virginia (1,450m), Blue Knob in Pennsylvania (882m), and the focal area of this study, Dans Mountain (882m) in western Maryland. Dans Mountain contains infertile, xeric habitats due to thin weathered soils on southeastern-facing convex slopes. These edaphically extreme situations also occur in the interior low plateau of Kentucky, Tennessee, and Indiana on bluff tops and narrow ridges including the Knobstone Escarpment. These fire-adapted communities have been dominated by Quercus and Pinus since the demise of Castanea dentata. The Quercus component providing essential mast for Neotoma magister and contributes to the complex canopy structures for northern long-eared bat Myotis septentrionalis and Appalachian cottontail Sylvilagus obscurus. Unlike other Quercus-dominated sites, old-growth forests on Dans Mountain, have adequate oak regeneration based on SILVAH 7 (primarily prinus, rubra, and alba) and have escaped the typical encroachment of Acer. Our study presents the recruitment dates, species compositions and densities, fire histories and deer densities that have resulted in continued oak-domination even on sites impacted by Lymantria dispar dispar. We suggest additional fire management and active measures to reduce deer densities to continue the suppression of Acer on these unique and often overlooked ecosystems.
Two image classification options for quantifying eastern redcedar (Juniperus virginiana) encroachment into the Cross Timbers Region
Daniel L. Hoff, Rodney E. Will, Chris B. Zou, John R. Weir, Mark S. Gregory, and Nathan D. Lillie
Graduate Research Assistant (DLH), Professor (REW), Associate Professor (CBZ), Research Associate (JRW), and Assistant Researcher (MSG), Department of Natural Resources Ecology and Management, Oklahoma State University; Natural Resource Specialist-GIS (NDL), Southern Plains Region, Bureau of Indian Affairs
Encroachment of eastern redcedar (ERC; Juniperus virginiana) into the Quercus-dominated Cross Timbers region of the Southern Great Plains is an ongoing management issue that affects ecosystem services and wildfire risk. The location and density of ERC canopy in the forest understory and midstory and in forest gaps are important information for fire managers seeking to estimate the behavior of fires or anticipate resources and attack methods needed to contain wildland fires. We compared a supervised classification method of 3-band (RGB) imagery taken from Google Earth and an unsupervised isocluster classification of multispectral RGB + Near Infrared imagery augmented with an NDVI and texture layer to identify the canopy of ERC on 124 forested field plots located in the Cross Timbers forest matrix of Pawnee and Payne Counties OK, USA. The 3-band imagery detected approximately 50% of the canopy area ([Actual Canopy Area (m2)] = 1.95 * [Classified Canopy Area (m2)] + 13.01, r2 = 0.78, n = 124). The multispectral imagery identified a greater proportion of ERC canopy area (95%) but had higher variance, particularly for plots with less ERC canopy area ([Actual Canopy Area] = 1.05 * [Classified Canopy Area] + 19.62, r2 = 0.43, n = 124). Both of these techniques can be used throughout the Cross Timbers region to identify the best locations for fuels reduction treatments, such as mastication or prescribed fire, to reduce wildfire risk and potential property damage.
Upland oak regeneration response to prescribed fire and canopy gap disturbances
Brian J. Izbicki, Heather D. Alexander, Brent R. Frey, Ryan W. McEwan, and Andrew I. Berry
Master’s student (BJI), Assistant Professors (HDA and BRF), Department of Forestry, Mississippi State University; Associate Professor (RWM), Department of Biology, University of Dayton; Natural Areas Director (AIB), Bernheim Arboretum and Research Forest
In the Central Hardwood and southern Appalachian regions, fire suppression contributes to oak regeneration failure and compositional shifts toward more shade-tolerant species. Prescribed fire may maintain upland oak ecosystems by removing competing species and increasing understory light; however, the most appropriate fire regimes to meet these objectives have yet to be identified. In Kentucky, single and multiple (2x, 3x) prescribed fires were implemented over 3 and 5-yr periods. Each growing season, canopy cover, annual growth, height, basal diameter and survival were quantified for oak (Quercus alba, Q. coccinea, Q. montana, Q. rubra, Q. velutina), hickory (Carya glabra, C. tomentosa), and competing red maple (Acer rubrum) and American beech (Fagus grandifolia) seedlings in three burned and two unburned plots at six treatment sites. Tree regeneration within canopy gaps of varying age and size within both burned and unburned areas was also quantified to identify gap influences on regeneration dynamics of oaks and competing species. Thus far, results suggest single fires are ineffective at promoting oak growth and survival, while multiple fires have modest positive impacts on oak growth and survival relative to competing species. This difference may be because single fires had no impact on canopy cover, whereas multiple fires caused ~10% reduction in canopy cover. Canopy gap data suggest gaps influence species composition and stand dynamics, with larger gaps having greater oak dominance than smaller gaps. This study could demonstrate how prescribed fire can help maintain upland oak ecosystems and determine future dynamics of upland forests with continued fire suppression.
On the origin(s) of Diplodia corticola: causal agent of cosmopolitan canker disease of Quercus spp.
D.K.H. Martin, C.M. Stauder, R.M. Turcotte, I.A. Munck, S.G. Aćimović, and M.T. Kasson
Plant Pathologists (DKHM and IAM), Forest Health Group Leader (RMT), Northeastern Area, USDA Forest Service; Extension Associate (SGA), College of Agriculture and Life Sciences, Cornell University; Assistant Professor (MTK) and Doctoral Candidate (CMS), Division of Plant and Soil Sciences, West Virginia University
Diplodia corticola (Dc) has emerged as an important canker pathogen of oaks in the US with introductions to ME, MA, WV, FL, and CA since 2010. In 2014, symptomatic red oaks (Quercus rubra) were observed in Seneca State Forest (SSF), WV exhibiting premature leaf drop with associated branch dieback, bleeding cankers and mortality. Wood plugs were sampled from canker margins, and a dominant fungus was identified molecularly as Diplodia corticola using the fungal barcoding gene (ITS). Two WV Dc isolates, 1 ME isolate, and 1 MA isolate were used to confirm pathogenicity on red oak seedlings. By 8 weeks post-inoculation, all inoculated seedlings had cankers while controls remained canker-free. Combined canker area means for WV Dc isolates were significantly larger (P < 0.05, 4.8cm2) than the controls (0.2cm2). All sampled Dc-inoculated stems showed vascular streaks and occlusions, while controls remained asymptomatic. Combined means for WV Dc isolates showed longer streaking (P < 0.05, 23.6cm) than the controls (0.0cm). Isolations of Dc from 80% of cankers and 25% of symptomatic vascular tissues across all Dc treatments confirmed pathogenicity of Dc. Due to the synchronous nature of outbreaks among geographically distinct disease epicenters in the U.S. following similar outbreaks in Europe, questions regarding the origin of these various Dc introductions have been raised. Phylogenetic analyses and mating type assays are currently being conducted to further explore these relationships and determine if global decline of oaks by D. corticola can be attributed to an invasive pathogen.
Assessing change in hardwood forests of the Wayne National Forest, southeastern Ohio
Stephen N. Matthews, David M. Hix, James D. Palus, Erin E. Andrew, P. Charles Goebel, and Donald Radcliffe.
Assistant Professor (SNM), Professors (DMH, PCG, and DR), and former Graduate Research Assistants (JPD and EEA), School of Environment and Natural Resources, The Ohio State University
Many forest ecosystems of the unglaciated Allegheny Plateau of southeastern Ohio are undergoing a conversion from oak–hickory (Quercus–Carya) species to future dominance by mesophytic species (e.g., Acer rubrum). In this study, we examined the changes in tagged trees that were measured on permanent plots during 1992-1993 on the Athens Unit of the Wayne National Forest. In 2016, we relocated 102 plots to measure the same tagged trees. Tagged, or witness, trees were the two living trees (DBH > 10.1 cm) closest to the plot center, and along with DBH (cm), we recorded the direction and distance of each tree from plot center. On returning to the plots, we relocated each tree if it was still alive or standing dead; we searched for the remnants of the tree if it was missing. There had been no harvesting on the plots; therefore, we believe the missing witness trees had fallen and decayed. Twenty-three species were represented as witness trees. Quercus alba was the most common across all plots; Acer saccharum and Fagus grandifolia (the second and third most common species) were concentrated on mesic northeast-facing slope ecological land types (ELT). Nearly 80% of the trees were still alive; about half of the mortality occurred on mesic ELTs. Growth varied considerably by species with Quercus rubra having the largest median increase in DBH. Among the ELTs, dry southwest slope ELTs had the smallest increase in DBH across the ELTs. These data capture the current dominance of oak in the overstory and reflect the initiation of change in a unique individual tree database across a diverse landscape.
Methods to tame Ailanthus in mixed oak forests, what works: prescribed fire, herbicides, or biological control?
Joanne Rebbeck, Todd Hutchinson, Louis Iverson, Matthew Peters, and Joan Jolliff
Research Plant Physiologist (JR), Research Ecologist (TH), Landscape Ecologist (LI), Ecologist (MP), and Biological Lab Technician (JJ), Northern Research Station, USDA Forest Service
Just as oaks can thrive in disturbed forests, so can non-natives trees like Ailanthus. Land managers need to be proactive and integrate control strategies into management activities at a landscape level to minimize the spread of non-natives. Unfortunately, current control recommendations for Ailanthus are inconsistent and often ineffective. Over the last several years, we have conducted studies to quantify the impacts of silvicultural practices on Ailanthus populations within a mixed oak forest landscape. We analyzed the presence and abundance of Ailanthus across the landscape in relation to prescribed fire, timber harvest, and stand structure. We found that recent timber harvest activity (<25 years) was the best predictor of Ailanthus presence. In other work, we found that fall stem-injections of imazapyr herbicide (6% a.i.) were 100% effective in killing Ailanthus trees and saplings compared to a winter herbicide treatment followed by a prescribed fire (86% decrease), or prescribed fire alone (10% increase). Post-burn, Ailanthus germinants and sprouts from top-killed saplings and trees were poor competitors with faster-growing post-fire woody regeneration as forest floor shading increased over subsequent years. More recently, we began testing a native fungus Verticillium nonalfalfae, as a biological control agent for Ailanthus. After two growing seasons, 78% of inoculated trees were either dead or 90-100% defoliated. Studies are ongoing to develop biocontrol methodologies, continue non-target risk assessments and study post-inoculation spread of the fungus. The goal is develop integrated recommendations for cost-effective control of Ailanthus in Appalachian forests.
Drought resistance and resilience of adult Quercus spp. after 60 years of experimentally manipulated fire regimes
Tyler Refsland, Benjamin Knapp, and Jennifer Fraterrigo
PhD Candidate (TR), Program in Ecology, Evolution and Conservation Biology, University of Illinois at Urbana-Champaign; Assistant Professor (BK), School of Natural Resources, University of Missouri; Associate Professor (JF), Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign
By killing fire intolerant individuals and reducing stand density, recurring fire disturbance may increase the drought resistance and resilience of adult oak (Quercus) trees. Past studies have shown that reduced stand density through thinning can at least temporarily reduce drought vulnerability of trees relative to unthinned stands. It remains unclear, however, how fire history affects forest functioning during drought. We compared markers of past drought stress found in tree rings of adult Quercus spp. growing under contrasting fire disturbance histories. In March 2015, we collected increment cores from 180 adults (≥ 10 cm DBH) within the University of Missouri Experimental Burn Unit forest sites in Mark Twain National Forest (MTNF). We compared the drought-induced decline in basal area increment (BAI) of adults located in one of three treatments (1) unburned controls (2) annually burned since 1951 and (3) periodic burned (four-year return interval) since 1951. We found adult oaks in annual and periodic burned plots experienced 10-15% reductions in BAI over the past 15 years relative to individuals in unburned plots, regardless of drought (P < 0.001). During the five most severe drought events of recent record (1953, 1954, 1980, 2007, 2010), we found adult trees in burned plots had marginally greater drought resistance and resilience than unburned trees, but not significantly so (P > 0.05). Our results suggest that adult oaks responded similarly to severe drought regardless of burn history, but that 60 years of annual and periodic fires may negatively affect tree growth during favorable wet years.
Red maple sprouting clumps dominate oaks after thinning and burning
Callie Jo Schweitzer, Yong Wang, and Dan Dey
Research Forester (CJS), Southern Research Station, USDA Forest Service; Professor (YW), Department of Biological and Environmental Sciences, Alabama A&M University; Research Forester and Project Leader (DD), Northern Research Station, USDA Forest Service
We studied the response of the regeneration cohort under various prescriptions aimed at restoring hardwood dominance in existing 50-year old pine-hardwood mixedwoods on the William B. Bankhead National Forest in northcentral Alabama. We evaluated various prescriptions combining thinning of pine followed by prescribed burning using a randomized complete block design with a three-by-three factorial treatment arrangement and four replications of each treatment. Treatments were combinations of three residual basal areas (heavy thin, 50 ft2 ac-1; light thin, 75 ft2 ac-1; and untreated control) with three burn frequencies (burns once every 3 years; burns once every 9 years, and unburned control). Stands were thinned June through December, and burned January through March. We examined the sprouting dynamics of the reproduction cohort in response to these disturbances. The number of clumps of sprouts for oak and red maple, as well as the number of sprouts per clump, increased for both species with infrequent and frequent fire. The majority of red maple sprouts were in the largest size class, while the majority of oak sprouts were half as tall as the red maple. Repeated fire with a heavy thin appear to be eliminating red maple from the sapling-midstory stratum, but recruitment seem inevitable due to the sprouting response of the juvenile cohort.
The use of fire and thinning to promote oak regeneration on private property in the Southern Cumberland Plateau
C. Ken Smith, Ellie Fowler, Nate Wilson, Nicole Nunley, and Victoria Schnaufer
Professor (CKS), Undergraduate Student (EF), Forest Manager (NW), Field Coordinator and GIS Specialist (NN), and Undergraduate Student (VS), Department of Forestry and Geology, The University of the South
Oak regeneration and recruitment of oak seedlings into the sapling stage is a major goal for many land managers in the southeastern US. Over the past seven years and on three sites, we have attempted to restore forest stands that were partially planted in loblolly pine (Pinus taeda) and eastern white pine (Pinus strobus) in the 1960s back to oak dominated stands. The primary objectives of this work were to examine the effectiveness of thinning and fire in the restoration of the native hardwood component, particularly with regard to our primary oak species (Quercus alba, Quercus montana, Quercus velutina, Quercus coccinea), to integrate undergraduate students into the management process (inventory, tree marking, prescribed fire), to create long-term research sites for student projects, and to create habitat diversity in a matrix of closed upland forest. After basal area reductions ranging from 21-60% and three fires, oak seedling densities increased from pre-treatment densities that ranged from 2000 – 9000 seedlings per ha to 8000 – 54,000 per ha two growing seasons after the third fire. After the third fire, mean litter depths ranged from 0.4 to 1.2 cm, with no statistical differences for litter and O Horizon depth among the three sites (P>.15). Browse of oak seedlings has been light with Vaccinium spp., Smilax spp., Sassafras albidum and Nyssa sylvatica the preferred species. We noted that logging technology and the resulting slash distribution greatly influenced the intensity and spread of the first fire at each site.
Value and status of state-and-transition models for oak systems: Appalachians and Central Hardwood Regions
James Smith, Randy Swaty, Kori Blankenship, Sarah Hagen, Kimberly Hall, Jeannie Patton, and Katherine Medlock
LANDFIRE Program Lead (JS), LANDFIRE Team Ecologist (RS), LANDFIRE Team Fire Ecologist (KB), LANDFIRE Team Spatial Scientist (SH), Climate Scientist (KH), LANDFIRE Team Communications Lead (JP), and Tennessee Project Director (KM), The Nature Conservancy
Quantitative state-and-transition ecosystem models, representing both current and historic time periods, are available for key oak ecosystems in the Central Hardwood and Appalachian regions. These models, originally developed by the LANDFIRE program and modified locally, document succession classes, key disturbance rates and often highlight areas where more information is needed. We illustrate their value to the conservation community, update participants on the current status of the model suite and solicit participation in a continuous improvement process for both the models and their application.
Oak decline – what we know today and what to do about it
Martin A. Spetich, Zhaofei Fan, Hong S. He, Wen J. Wang, Michael K. Crosby, and Stephen R. Shifley
Research Forest Ecologist (MAS), Southern Research Station, USDA Forest Service; Associate Professor (ZF), School of Forestry & Wildlife Sciences, Auburn University; Professor (HSH) and Research Associate (WJW), Department of Forestry, University of Missouri; Assistant Professor (MKC), Department of Natural Sciences, Shorter University; Research Forester (SRS), Northern Research Station, USDA Forest Service
Oak decline was the focus of the last Oak Symposium in 2002. Since then, in the Ozark Highlands alone over 60.5% of red oak dominated forest has been severely impacted by oak decline. This is a synthesis of our past fifteen years of research into oak decline where our overall objective was to develop management methods to reduce the area of decline susceptible forest across the eastern United States. Our research methods included intensive inventories at seedling and forest stand scales, while analyzing Forest Inventory and Analysis data for landscape and regional scale modeling. Within one year of oak decline onset at the stand scale the number of standing dead northern red oak (Quercus rubra L.) trees increased by 55% (p=0.029). Across the Ozark Highlands 3.6 million ha of northern red oak, 0.4 million ha of white oak (Quercus alba) and 0.28 million ha of non-oak dominated forests had severe oak decline between 2006 to 2010. While model simulations across a 0.43 million ha area through the next century predict a reduction of potential oak decline sites by 25% if historic fire frequencies are re-established. However, simulations by harvesting alone resulted in only a of 3% reduction of high risk sites over doing nothing. Our analysis across eleven states indicates that red oak had 7% greater crown dieback than white oak during 2003 to 2010 following drought. Results indicate methods to reduce decline susceptible forests to include fire, favoring decline resistant species and managing physiological age of susceptible trees.
Upland oak and mesophyte seedling morphological traits in response to prescribed fire
Evangelin Von Boeckman, Heather D. Alexander, Brian Izbicki, and Emily Babl
Undergraduate Researcher (EVB), Assistant Professor (HDA), and Graduate students (BI and EB), Department of Forestry, Forest and Wildlife Research Center, Mississippi State University
Morphological traits of upland oak (Quercus) seedlings are a direct expression of resource allocation, and fire is believed to alter resource allocation. There have been few studies in upland oak forests that identify a relationship between above and below ground traits of seedlings in response to fire. The objective of this study was to quantify species distribution of resources to various structural components, and whether oaks or shade-tolerant, fire sensitive species (i.e. mesophytes) differ. To address this issue, we chose seven species in Kentucky, which included upland oaks (Q. alba, Q. coccinea, and Q. montana) and hypothesized mesophytes (Acer rubrum, A. saccharum, Carya glabra, and Fagus grandifolia) that were sampled in various fire treatments (unburned,1x, 2x, and 3x burned). In the field, environmental variables such as canopy cover and soil organic layer depth and seedling traits such as height, basal diameter, and root collar were measured before seedling harvest; lab procedures included measurement of specific leaf area, leaf thickness, and nitrogen content to understand photosynthetic capabilities, along with the development of allometric equations for linking above and below-ground traits. We hypothesized oak species will allocate more resources to below-ground structures with increased fire treatments compared to mesophytes due to oaks’ physiological and morphological traits to withstand fire. This research could contribute to the further understanding of oak regeneration response to prescribed fire and the pattern of resource allocation between oaks and mesophytes.