Oak Ecosystem Restoration and Maintenance in Southern Illinois (original) (raw)
Related papers
2008
We document an increase in oak and hickory advance regeneration, depending on landscape position, in the sixth year following mechanical thinning and repeated prescribed fires in southern Ohio, USA. Oak-dominated communities provide a multitude of human and natural resource values throughout the eastern United States, but their long-term sustainability is threatened throughout the region by poor regeneration. This study was established to assess regeneration following midstory thinning (late 2000) and prescribed fire application (2001 and 2005) at two sites in southern Ohio. Each of the four 20+ ha treatment units (two thin and burn, two untreated controls) were modeled for long-term moisture regime using the integrated moisture index (IMI), and a 50 m grid of sampling points was established throughout the units. Vegetation and canopy openness were sampled at each gridpoint before and after treatments, in 2000, 2001, 2004, and 2006. The thin and burn treatment generally resulted in more advance regeneration (>50 cm height) of oak and hickory. The second fires in 2005 created additional landscape heterogeneity by causing variable tree mortality, and thus canopy openness, across the IMI gradient. The drier landscape positions generally had more intense fires, more canopy openness, and more oak and hickory advance regeneration; several other tree species also exhibited marked landscape variation in regeneration after treatments. Though advance regeneration of several competing species became abundant after the initial treatments, the second fires reduced the high densities of the two major competitors, Acer rubrum and Liriodendron tulipifera. Two simple models were developed: (1) a model of oak ''competitiveness'' based on the plot data related to advance regeneration of oaks and competitors and (2) a model estimating the probability of a plot becoming 'competitive for oak' based on canopy openness, IMI class, and number of oak and hickory seedlings present. For dry or intermediate sites with at least 5000 oak and hickory seedlings/ha, opening the canopy to 8.5-19% followed by at least two fires should promote oak and hickory to be 'competitive' over about 50% of the area. However, no appreciable oak and hickory regeneration developed on mesic sites. Overall, these results suggest promise for partial harvesting and repeated fires as a management strategy to reverse the accelerating loss of oak dominance in the central hardwoods region. Published by Elsevier B.V.
Forest Ecology and Management, 2005
This study quantifies prescribed fire effects at four sites in southern Ohio, from 1995 to 2002. Each site had three treatment units: an unburned control, a unit burned 2 x (1996 and 1999), and a unit burned 4 x (1996-1 999). Vegetation plots were stratified by an integrated moisture index (IMI) into xeric, intermediate, and mesic classes. Prior to treatments, oak (Quercus spp.) and hickory (Carya spp.) comprised 74-83% of basal area among sites but shade-tolerant species (e.g., Acer rubmm) were abundant in the midstory and completely dominated the sapling layer. Fires were conducted in March and April. Fire intensity, estimated by temperature-sensitive paints, was highest on the 2 x bum units. Fires had little effect on large tree (>25 cm DBH) density and stand basal area. By contrast, the density of small trees (10-25 cm DBH) was reduced by 31% on 2 x burn units and by 19% on 4x burn units. "Fire-induced" mortality (i.e., mortality on bum units above that of unburned units) for the most common species of small trees was: A. rubrum = 33%; Quercus alba = 17%; Carya spp. = 13%; Nyssa sylvatica = 10%; Acer saccharwn = 4%; Quercus prinus = 2%. Sapling density was reduced by 86% on burn treatments. Despite reduced small tree and sapling densities on burned units, canopy openness, estimated by hemispherical photography, remained low (<6%). In general, the composition of tree regeneration was not substantially altered by fire treatments. On bum units, a significant initial decrease in A. rubncrn seedling density and a significant increase in Liriodendron tulipifera from the seed bank did not persist throughout the study. Oak + hickory seedling density was not significantly affected by fire nor was the density of shade-tolerant seedlings. Post-treatment (2002) sampling of large seedlings (>30 cm height) indicated no significant differences in the abundance of oak + hickory nor that of shade-tolerant seedlings among fire treatments. For most vegetation response variables, fire effects tended to be similar among IMI classes. The application of fire alone, without partial harvesting, failed to improve oak regeneration consistently. However, given that two fires reduced stand density, the longer term application of periodic fire, coupled with natural gap dynamics, may still be a feasible management strategy for improving the sustainability of oak forests where harvesting is not permitted or desired.
Journal of Forestry, 2012
Prescribed fires are increasingly implemented throughout eastern deciduous forests to accomplish various management objectives, including maintenance of oak-dominated (Quercus spp.) forests. Despite a regional research-based understanding of prehistoric and historic fire regimes, a parallel understanding of contemporary fire use to preserve oak forests is only emerging, and with somewhat inconsistent results. For prescribed fires to be effective, they must positively influence oak regeneration at one or more critical life stages: pollination, flowering, seed set, germination, establishment, seedling development, and release into the canopy. We posit that a simplistic view of the relationship between fire and oak forests has led to a departure from an ecologically based management approach with prescribed fire. Here, we call for a refinement in our thinking to improve the match between management tools and objectives and provide some guidelines for thinking more ecologically about when and where to apply fire on the landscape to sustain oak-dominated forests.
Characteristics of mixed-oak forest ecosystems in southern Ohio prior to the reintroduction of fire
2003
Mixed-oak forests occupied much of the Unglaciated Allegheny Plateau region of southern Ohio at the onset of Euro-American settlement (ca. 1800). Historically, Native Americans used fire to manage the landscape and fire was frequent throughout the 19 th and early 20 th centuries during extensive forest harvesting and then re-growth. Today, though mixed-oak forests remain dominant across much of the region, oak regeneration is often poor as other tree species (e.g., maples) are becoming much more abundant. This shift has occurred concurrently with fire suppression policies that began in 1923. A multidisciplinary experiment was initiated in southern Ohio to explore the use of prescribed fire as a tool to improve the sustainability of mixed-oak forests. This report describes the experimental design and study areas, and provides baseline data on ecosystem characteristics prior to prescribed fire treatments. Chapters describe forest history, an integrated moisture index, geology and soils, understory light environments, understory vegetation, tree regeneration, overstory vegetation, foliar nutrient status, arthropods, and breeding birds.
Refining the oak-fire hypothesis for managment of oak-dominated forests of the eastern United States
2012
Prescribed fires are increasingly implemented throughout eastern deciduous forests to accomplish various management objectives, including maintenance of oak-dominated (Quercus spp.) forests. Despite a regional research-based understanding of prehistoric and historic fire regimes, a parallel understanding of contemporary fire use to preserve oak forests is only emerging, and with somewhat inconsistent results. For prescribed fires to be effective, they must positively influence oak regeneration at one or more critical life stages: pollination, flowering, seed set, germination, establishment, seedling development, and release into the canopy. We posit that a simplistic view of the relationship between fire and oak forests has led to a departure from an ecologically based management approach with prescribed fire. Here, we call for a refinement in our thinking to improve the match between management tools and objectives and provide some guidelines for thinking more ecologically about when and where to apply fire on the landscape to sustain oak-dominated forests.
Forest Ecology and Management, 2012
The survival and growth of oak advance regeneration is often limited by shade-tolerant species that are abundant in the understory of oak stands. Evidence of historic burning has prompted the use of prescribed fire as a tool to improve the competitive status of oak regeneration in mature stands. A primary shortfall of fire effects research in oak forests has been a lack of long-term studies on the effects of multiple fires. Here we describe the effects of repeated fires on stand structure and tree regeneration over a 13year period in mature mixed-oak forests located in southern Ohio, USA. Three stands were burned 3-5 times from 1996 to 2005 with low-intensity dormant-season fires, and two stands remained unburned. Woody vegetation was sampled periodically on nine 0.125 ha plots per stand. Plots were located across the upland landscape and were characterized by an Integrated Moisture Index. Fire altered stand structure by reducing the density of large saplings (3.0-9.9 cm DBH) and midstory trees (10-25 cm DBH) by 76% and 34%, respectively. Fire had little impact on trees >25 cm DBH. Small saplings (1.4 m tall to 2.9 cm DBH) were dynamic over time on dry plots that were burned. After being repeatedly topkilled from year 1-8, the small sapling layer had redeveloped on dry burned plots by year 13 and species composition had shifted from dominance by shade-tolerant species to a more equal distribution of shade-tolerants, oaks + hickories, and sassafras. The density of oak + hickory and sassafras advance regeneration (stems 30 cm tall to 2.9 cm DBH) was significantly greater on burned plots than on unburned plots in year 13, though variability among plots was high. Advance regeneration of shade-tolerant species was equally abundant on burned and unburned plots. Density of oak + hickory advance regeneration in year 13 was positively related to its weighted frequency (a surrogate for size and abundance) in year 0 (r 2 = 0.67, p < 0.0001) and inversely related to stand density (r 2 = 0.33, p < 0.0001) and canopy cover (r 2 = 0.31, p < 0.0001), both of which were reduced by fire. Although oak + hickory advance regeneration was more abundant on burned plots, we conclude that other methods (e.g., herbicide, partial cutting) are necessary to further reduce stand density and promote the development of larger oak + hickory regeneration, particularly on mesic sites.
Canadian Journal of Forest Research, 2019
Understanding the effects of fire on advance regeneration of oak (Quercus L.) species and their competitors is an important step in determining the role of prescribed fire in regenerating and restoring upland oak ecosystems. Our study aimed to understand how dormant-season prescribed fire affects advance regeneration of chinkapin oak (Quercus muehlenbergii Engelm.), black oak (Quercus velutina Lam.), and their major competitors at sites targeted for woodland restoration and management. We analyzed relationships between stem size and survival probability; determined the effect of fire temperature on survival probability; and compared how mortality, sprouting, and survival differed among species. For chinkapin oak, black oak, and bitternut hickory (Carya cordiformis (Wangenh.) K. Koch), mortality was low and rate of sprouting was high after shoot dieback. Initial basal diameter was significantly related to survival probability after one fire for all species except chinkapin oak and bl...
Silvicultural considerations for managing fire-dependent oak woodland ecosystems
2014
Oak woodlands are characterized by open understories and dense ground flora composed of forbs, grasses, and sedges. They once were common in the western Central Hardwood Forest region and the prairie-forest transition zone where lowintensity fires occurred frequently. In the absence of fire, many of the woodland ecosystems throughout much of this region have succeeded to compositions and structures resembling those of mesophytic forests. Consequently, forest managers are increasingly interested in restoring the structure and composition of oak woodlands by thinning and prescribed burning. Presently, there are few guidelines based upon silvicultural principles for restoring and managing woodland ecosystems. However, many silvicultural concepts, principles, and methods used for managing forests can also be used for managing woodlands, but the application and timing of treatments may differ to meet the objectives of woodland management. In this paper, we summarize findings from a number of studies and offer guidelines for restoring and managing oak woodlands.