Upland Oak Forests Research Articles

Habitat type influences parasite load in Algerian Psammodromus (Psammodromus algirus) lizards

Understanding how habitat type and deterioration may affect parasitism is important in assessing the effects of human-induced environmental change on host–parasite dynamics. In this study, we examined inter-population differences in parasite load in the Mediterranean lizard Psammodromus algirus (Linnaeus, 1758). We analyzed prevalence and intensity of infection by blood parasites and ectoparasites in two populations separated by a 400 m elevational gradient and with different habitat types that also differed in the degree of human alteration. We also compared data obtained from the same populations 10 years later to assess whether there have been temporary changes in parasite loads. Results showed that prevalence and intensity of blood parasites were higher in the deteriorated lowland holm oak forest population than in the well-preserved upland oak forest. In contrast, the prevalence and intensity of infection by Ixodes Latreille, 1795 ticks was higher in the upland oak forest population. Individuals from the lowland population were in poorer condition. Intensities of infection by blood parasites and ectoparasites have decreased significantly from 2005–2006 to 2016 in both populations. Our results suggest that inter-population differences in parasite load may be explained by differences in habitat characteristics. This study contributes to the identification of ecosystems and habitats that are most sensitive to prevalence and intensity of infection by parasites.

Soil composition and properties: a case study of Shilovsky Upland Oak Forest (Russia)

The paper deals with environmental properties properties of the soil cover taken from the Upland Oak Forest (Voronezh region, Russia). Morphological structure, physical and chemical properties, humus content and nutrients in urban forest soils are important for assessing their ecological status. Forest soils are characterized by a low degree of disturbance and close to the morphological structure to of the natural analogs outside the cities. Dark grey forest-steppe soils have the most favorable environmental properties. The low contents of total forms of heavy metals allows for the consideration of these soils in the category of environmentally friendly. The highest contents are characterized by the humus horizons of dark grey and grey forest-steppe soils, which maximum content is for Mn 754, Zn 49, Cu 13, Pb 16, Ni 25, Cd 0.26, Cr 60, Co 9, As 0.1, and for Hg 0.1 mg/kg. The content of mobile forms of heavy metals reaches Mn 105, Zn 0.9, Cu -.5, Pb 1.8, Ni 2.6, Cd 0.08, Cr 0.2, and Co 2.9 mg/kg. The obtained data can be used to assess the degree of disturbance and anthropogenic impacts on anthropogenic-altered urban soils. The study area may be used as a background in assessment of the urban environment.

The relationship of spore (mosses) and seed plants with mesorelief types of oak forests

A transect from the watershed to Voronezh reservoir storage has been made to study the influence of geomorphological factors on the biodiversity level of mosses and vascular plants in Voronezh upland oak forest (East of Russia). Taxonomic, ecological, biological, and geographical analyses of flora have been done. Geobotanical research methods have been used to assess phytocoenosis. Certain laws in ecotopic plants distribution and projective covering have been scored; the parameters to assess ecosystem biodiversity have been proposed and used in the studies. The three chosen zones are very different in a number of natural indicators, especially in mesorelief type and moisture degree. Mosses and vascular plants, while developing the habitats, are differently manifested in these areas. Very often they do not reflect landscape and environment peculiarities. But, according to the results, most plant species (over 55.9%), belong to mesophytes no matter which zone they grow. So, the near-valley slope zone of the Voronezh River is poor in species richness and density, genus and family diversity. These parameters increase towards the plateau.

Многолетний опыт по влиянию рубок ухода на нагорные искусственные насаждения дуба черешчатого южной лесостепи

The results of a 60-year experience on the effect of thinning on the stability and productivity of the stand of English oak of artificial origin in the Tellerman experimental forestry of the Institute of Forestry of the Russian Academy of Sciences have been summed up. Cleaning cuttings was carried out on permanent trial plots in 2 ways - by the grassroots method and by method of V.G. Nesterov with an intensity of up to 35% in stock 3 times. In the long-term dynamics, the ranking of stands on the average height and diameter, the number of trunks and the sum of cross-sectional areas, stock and total productivity, given by the intensity and the method of thinning, was mainly preserved. With increasing felling intensity, regardless of their method, relative increment and change in the stock have increased. In conditions of periodic moisture deficiency and accompanying damage to the leaves by insects, the stands could not restore previous trajectory of stock after the third felling. After 60 years of age, the stock of forest stands has not practically increased. Regardless of the intensity and the method, cleaning cutting contributed to the stability of growth rate of the stands. In the control, the stock decreased as a result of wave detachment, including large trunks. The stock of large trunks by the age of 80 years in the options with cutting was higher than in control one by an average of 17%. In order to reduce the risk of stock reduction by the age of ripeness in the upland oak forests of the southern forest-steppe, it is recommended to limit the period of intensive cutting up to 40 years. In this case, the trees will be able to form well-developed crowns at the end of the period of rapid growth. During unfavorable periods there is a decrease in the productivity of plantations and a decrease in the effect of thinning, which is important to take into account when predicting the growth of stands.

Protected plants on the territory of the Racheiskii forest natural monuments (Samara Region)

The paper contains species composition of the rare taxa growing in specially protected natural areas in the Samara Region Gremiachii, the source of Usa river, Malousinskie upland pine and oak forests, Racheiskaia taiga, Racheiskie skaly and Seven springs, located in the Racheiskii forest (upper reaches of the Usa river basin). The authors assess their occurrence in the protected areas. They have established that 98 species of rare vascular plants that included in the Red Book of the Samara Region grow here, among them 4 species are included in the Red Book of the Russian Federation (Iris aphylla L., Fritillaria ruthenica Wikstr., Cypripedium calceolus L., Neottiantha cucullata (L.) Schlechter). Another 17 species need constant monitoring and surveillance. Previously presented for the Usa river basin Cotoneaster alaunicus Golitsin, Dactyloriza longifolia (L.) Aver. and Jurinea ewersmannii Bunge have not been found, their location in the region requires additional research. For the revision of rare plant species the authors have used published materials and unpublished materials of expeditionary research integrated in Information-analytical system Salix. The obtained materials make it possible to correct the natural monuments system by combining identical natural-territorial complexes.

Alterations to the fuel bed after single and repeated prescribed fires in an Appalachian hardwood forest

To manage upland oak forests across the central and southern Appalachian mountain and plateau regions, prescribed fire is applied more frequently and across larger areas than in the recent past. The often stated objective is to reduce fuels, but there is a paucity of information on the impacts of repeated burning on fuels, including woody materials and the soil organic layer. These are complex components of forest ecosystems with significant impacts on nutrient and carbon cycling, forest successional dynamics, and soil protection from loss via erosion. Thus, understanding fuel bed response to prescribed fire is essential for predicting future forest function. Using study sites distributed across a range of landscape positions in the Daniel Boone National Forest on the Cumberland Plateau of eastern Kentucky, we examined changes to the fuel bed over six years in response to a single fire (burned once in six years), repeated fire (burned four times in six years), and fire-excluded treatments to determine prescribed fire impacts on fuel loads and mineral soil exposure. Prior to burning, fuel loads were generally similar among landscape positions, although the duff layer was lowest on sub-mesic and greatest on sub-xeric positions. A single fire reduced duff depth by 50%, whereas repeated burning led to depth reductions of >60%. Repeated burning also significantly increased mineral soil exposure (25%) compared to single burn and fire-excluded (2–4%) treatments, with the greatest effects on sub-mesic and intermediate landscape positions. Repeated burning significantly reduced fine woody (1-h) fuels, but only after three burns, whereas fine fuel mass on sites burned once was similar to those where fire was excluded. There were no statistically significant effects of burning on large woody fuels (100- and 1000-h fuels). Overall, the primary impact of prescribed fire on the fuel bed was to consume the organic horizon and expose mineral soil, which has the potential to reduce fuel continuity for subsequent burns. Fire behavior in this region is driven primarily by fine fuels (litter and duff) and fuel continuity, both of which recover in relatively short periods of one to several years. Reduction of woody fuels is more intractable under a prescribed fire regime.

Количественная оценка популяционных стратегий представителей древесного яруса воронежской нагорной дубравы

The article presents the results of the investigation of the species composition of trees at the canopy layer in upland oak forest on the sample slots. On the basis of the trees-presence formula the degree of realization the competitiveness, tolerance and reactive strategies was determined. It was found that the quantity of Quercus robur increases the competitiveness degree of the community. The contribution of other trees in the amplification of this population strategy is insignificant. Relatively high values of competitiveness are forming oaks in the amount not less than 40% of the total number of trees.

Influence of resource availability onJuniperus virginianaexpansion in a forest–prairie ecotone

AbstractWoody plant expansion into grasslands and savannas is a global concern. Rapid expansion ofJuniperus virginiana, a tree native to North America, has profound ecological consequences. We used transplantedJ. virginianaseedlings to investigate the role of resource availability onJ. virginianaexpansion following the removal of fire, the factor historically limiting range expansion of this fire‐intolerant species. We evaluatedJ. virginianaseedling survival and seedling growth, two important phases in woody plant expansion, relative to two belowground resource factors, plant‐available soil water (soil clay content, an index of plant‐available soil water) and plant‐available nitrogen (PAN), and an aboveground factor, photosynthetic active radiation (PAR). In three plant communities associated with an oak forest–tallgrass prairie ecotone, we transplanted 2‐yr‐oldJ. virginianaseedlings in a systematic grid design and measuredJ. virginianaseedling survival and growth 8, 20, and 30 months following the transplant. We also measured soil clay content, PAN, and PAR in 1‐m2quadrats centered on each transplanted seedling. We employed path analysis at two spatial scales (144 and 2916 m2) to compare the role of resource factors in seedling growth and survival.Juniperus virginianaseedling survival was about 10% greater in tallgrass prairie and upland oak forest than in the old field, and seedling growth in tallgrass prairie exceeded the two other communities by about a factor of five. Tallgrass prairie in our study area is clearly more vulnerable to expansion ofJ. virginianathan the other two plant communities. Survival and growth were controlled largely by available light (PAR) and secondarily by plant‐available soil water, indexed by soil clay content. In all three vegetation types and at both fine and coarse scales, soil clay content also exerted an indirect effect, possibly by mitigating the influence of light. Results of this study suggest that soil distribution maps and associated ecological site designations might be useful for directingJ. virginianamanagement in the oak forest–tallgrass prairie ecotone by identifying the potential hotspots of invasion.

The avifauna of the National Nature Park "Homilshanski Lisy"

In the recreational zone of "Homilshanski Lisy" National Park 137 species of birds were identified during the period 1980–2015, of which 127 species nest, 8 winter, and 2 observed during the spring migration. The nesting species are distributed in 4 ecological groups dominated by dendrophylls (67 species), with fewer limnophylls-fresh water species (29), campophylls-open country species (16) and sclerophylls (11). Among the nesting birds 11 landscape-genetic faunal assemblages were distinguished, dominated by typical nemoral-woodland (19%), tropical (14%) and forest-steppe (13%) species. The average density of the birds nesting in the park amounts to 1.2 ± 0.2 with n overall density of 148.3 pairs/km route line. The habitat distribution of the bird population was relatively even. The most intensively populated habitat was upland oak forest, the least were pine and mixed forests. It was found that the communities of breeding birds in tree plantations changed due to the natural aging process of forests, which has led to an increase in the number of birds of prey (Falconiiformes), woodpeckers (Piciformes), secondary hollow-nesting birds. The bird communities of floodplain and steppe meadows, as well as habitats in residential areas subject to constant recreational pressure, changed under the pressure of anthropogenic loading. The favorable natural and geographical location of the park and the diversity of its habitats contributed to the emergence in the list of fauna of which are expanding their range. Analysis of the dominant species in the community points to a significant negative impact of recreational pressure on all habitats of the park. The dominant birds in the pinewood community list included only one campophyll, tree pipit (Anthus trivialis L.). For the steppe meadows, in addition to the dominant colonial birds that nest in holes , the yellow wagtail (Motacilla flava L.) was marked as subdominant. In general, in the recreational area of NPP "Homilshanski Lisy" 30 common species (24.2%, total abundance 0.198) nest on the ground. The variety and balance of breeding bird communities in most habitats is stable, but in the meadow ecosystem communities the uniformity of the distribution of species abundance is being significantly disrupted. The Jacquard and Sorenson performance indices for floodplain and steppe meadows are 0.4 and 0.5, and for grove and pine woods, respectively, 0.7 and 0.8. Taking into account the data of the cluster analysis, the distribution curves of shared abundance and participation indicatee sinanthropic breeding bird communities. It follows that anthropogenic pressure exerts the most significant effect on the birds’ occupation of breeding habitats in the recreational zone NPP "Homilshanski Lisy". The highest performance is characterized by the condition of the avifauna of forest habitats, such as oak forest and pine woods, the most threatened breeding bird communities being those of floodplain meadows.

К проблеме повышения устойчивости насаждений Воронежской нагорной дубравы

The article is devoted to the definition of forest pathology condition of plantations of biology (for-est) nature monument "Old-growth areas of upland oak forests", located in the quarter 52 of Pravobe-rezhnoe forestry of Prigorodny district forest, Voronezh region. Definition of certain classes of biological sustainability of forests and evaluation of its sanitary condition during the examination of trees on test plots is carried out. The factors reducing the stability of oak trees are indentified and analyzed. Forest pa-thology plants condition were evaluated for three classes of biological sustainability. Sanitary condition of plantations is evaluated.

Радиоэкологический мониторинг в лесных экосистемах Центральной лесостепи России

It was found that during the period of observation at hospitals forestry radiation monitoring in fresh upland oak forests and wet Pinetum compositum main drive radiocaesium is oak, which is connected, apparently, with its biological and ecological features. It is also clear that, along with the biological specificity of a particular tree species, an important role in the accumulation of woody plants play a cesium type of forest growth conditions (trophicity, humidity). In woody plants most contaminated surface tissues that make up the crust. Further, the degree of contamination, followed by leaves (needles), small branches, wood with bark and wood peeled, where radiocaesium virtually identified.

Efficacy and Associated Factors of Even- and Uneven-Aged Management to Promote Oak Regeneration in the Missouri Ozarks

Oak regeneration problems have been noted in the Missouri Ozarks and elsewhere in the eastern United States. Alteration of disturbance regimes, competition from nonoak species, and high overstory stocking are believed to be major barriers that impede oak regeneration. We studied regeneration in upland oak forests that were harvested by both even-aged (clearcutting) and uneven-aged (single-tree selection and group selection) regeneration methods, focusing on differences in oak regeneration among stands that received alternative harvest treatments. Ten years after treatments, the density of oak regeneration generally increased with increased removal of overstory trees, but only the clearcutting treatment resulted in a statistically significant increase in the density of oak seedlings and saplings over that in the no harvest treatment (the control). There were no differences among treatments in the relative proportions of oak seedlings and saplings as a whole or by size classes among the treatments. Successful oak regeneration after removal of overstory trees highly depends on the number and size of advance oak reproduction and is closely related to site conditions such as aspect and bedrock geology. Both site factors and advance oak reproduction must be considered when a regeneration method to promote oak is chosen. Compared with the uneven-aged methods (single-tree selection and group selection), clearcutting favored the red oak species over the white oak species.

Structure and composition of an oak-hickory forest after over 60 years of repeated prescribed burning in Missouri, U.S.A

Prescribed fire is often used in upland oak forests to achieve objectives related to woodland restoration or oak regeneration. While not uncommon for prescriptions to include repeated burning at short fire return intervals, long-term frequent fire effects in hardwood forests have rarely been quantified. We describe the effects of over 60years of repeated prescribed burning on stand structure and composition in a Missouri Ozark oak-hickory forest. Data were collected in 2010 and 2013 from 40×40m plots arranged in a randomized complete block design with two blocks and three treatments: an unburned control (Control), annual prescribed fire (Annual; one-year fire return interval), and periodic prescribed fire (Periodic; four-year fire return interval). In 2013, the diameter distribution of the Control was an exponential decay, whereas those in both burn treatments were unimodal. Repeated prescribed burning, especially at four-year fire return intervals, reduced overstory density and canopy cover and shifted overstory composition from a mixture of white oak species, red oak species, and hickories to primarily white oak species. Although small-diameter stems were top-killed on Periodic plots, resprouting created a dense mid-story of small stature saplings. In contrast, Annual plots were virtually void of woody seedlings and saplings. There was no apparent tree recruitment on either Annual or Periodic plots. The abundance, richness, diversity, and evenness of the understory plant community were greater on the burned plots than on the Control plots, with forbs dominating the Annual plots and woody species dominating the Control plots. Periodic plots included a mixture of forbs and woody species, and graminoids were not common in any plots. Understory species richness per square meter was nearly three times greater on both burn treatments relative to the Control. Our results indicate that long-term, repeated prescribed burning can approximate woodland conditions. However, the lack of tree recruitment suggests that periods without fire are critical for replacing overstory trees. Moreover, additional treatments such as mechanical thinning may be important for modifying the understory environment to benefit graminoids or for reaching management objectives on desirable timescales.

Proactive Restoration: Planning, Implementation, and Early Results of Silvicultural Strategies for Increasing Resilience against Gypsy Moth Infestation in Upland Oak Forests on the Daniel Boone National Forest, Kentucky

Determining targets in forest restoration is a complicated task that can be facilitated by cooperative partnerships. Too often restoration plans are implemented after adverse events that cause widespread tree mortality, such as drought or insect outbreaks, have occurred. Reactive management precludes the use of preemptive management techniques that can result in more effective restoration. The potential recognition and risks associated with a large-scale mortality event cultivated a proactive partnership among managers, stakeholders, and researchers on the Daniel Boone National Forest in Kentucky. This partnership resulted in the development of innovative proactive approaches to mitigate the negative impacts of threat of declining forest health, thus reducing the need for untested and expensive postdisturbance restorative operations. The partnership comprised four Research Work Units in the USDA Forest Service (including the Northern and Southern Research Stations), three universities (one land grant and two liberal arts), two natural resource state agencies, private logging contractors, an electrical utility, and National Forest system personnel at the district, forest supervisor, and Washington office levels. We tested forest management prescriptions designed to meet targets for future forest conditions. The goal of the silviculture treatments was to improve forest health and productivity to increase resilience to and/or avoidance of exotic invasive insect defoliation and oak decline. Treatments varied from high levels of disturbance to low levels of disturbance and ranged from even-aged regeneration treatments coupled with prescribed burning to thinning. Research assessed the alteration in species composition and stand structure, the projected regeneration outcomes and the costs and operational efficacy of mechanized forest operations used to implement the treatments. The relatively large scale of the study and diversity of treatments has afforded additional multidisciplinary research activities. Via partnership building and information and technology sharing, this project has been sustained for 10 years.

Development of Prescribed Fire as a Silvicultural Tool for the Upland Oak Forests of the Eastern United States

In the past 40 years, the perception of periodic fire in upland oak (Quercus spp.) forests in the eastern United States has changed dramatically. Once thought of as a wholly destructive force, periodic fire is now considered an important disturbance whose absence is a major contributing factor to oak regeneration problems. This change in attitude and the concurrent development of prescribed fire as an accepted oak regeneration tool are due to several research—management partnerships. Starting in the 1970s, cooperative research between the USDA Forest Service and various land management agencies examined fire effects in mature, uncut oak forests. These failed to regenerate oak but identified some key limitations leading to the failures. Subsequent research in the 1990s shifted to oak shelterwoods and ultimately identified hot spring fires as a treatment that would regenerate oak. Since then, other partnerships have expanded fire–oak research to include woodland restoration burning. This paper reviews the history of cooperative fire–oak research over the past 40 years and the key role partnerships have played in the development of current prescribed fire practices in upland oak forests.

Increasing Red Maple Leaf Litter Alters Decomposition Rates and Nitrogen Cycling in Historically Oak-Dominated Forests of the Eastern U.S.

Without canopy-opening fire disturbances, shade-tolerant, fire-sensitive species like red maple (Acer rubrum L.) proliferate in many historically oak-dominated forests of the eastern U.S. Here, we evaluate potential implications of increased red maple dominance in upland oak forests of Kentucky on rates of leaf litter decomposition and nitrogen (N) cycling. Over 5 years, we evaluated mass loss of leaf litter and changes in total N and carbon (C) within six leaf litter treatments comprised of scarlet oak, chestnut oak, and red maple, and three mixed treatments of increasing red maple contribution to the leaf litter pool (25, 50, and 75% red maple). Over a 1.5-year period, we conducted a plot-level leaf litter manipulation study using the same treatments plus a control and assessed changes in net nitrification, ammonification, and N mineralization within leaf litter and upper (0–5 cm depth) mineral soil horizons. Red maple leaf litter contained more “fast” decomposing material and initially lost mass faster than either oak species. All litter treatments immobilized N during initial stages of decomposition, but the degree of immobilization decreased with decreasing red maple contribution. The leaf litter plot-level experiment confirmed slower N mineralization rates for red maple only plots compared to chestnut oak plots. As red maple increases, initial leaf litter decomposition rates will increase, leading to lower fuel loads and more N immobilization from the surrounding environment. These changes may reduce forest flammability and resource availability and promote red maple expansion and thereby the “mesophication” of eastern forests of the U.S.

Water regime of upland oak forests of the south Russian forest steppe

In the southern forest steppe, the upland oak forests on loamy dark grey soils, which have the automorphic mode of water supply, usually endure droughts during the second half of the vegetative season due to the creation and use by biogeocenoses of some moisture reserves into soil and groundwater (GW), which are accessible to deep layers of root systems of trees. Two shallow sandy horizons interlaying moraine loams of the Dnieper glaciation at altitudes of 120 and 143 m above sea level serve as collectors and transporters of GW, the table of which is 10-15 m lower than the surface of the watershed plateaus and terraces. By autumn, trees desiccate subsoil horizons to the capillary fringe of GW. In early spring, the moisture of dried horizons is restored. The reserves of GW permit the upland oak forests to preserve rather high values of predawn leaf water potential such as Ψ PD ≥ −0.8 MPa despite the decrease in water potential of soil at a depth of 0-2 m of the soil layer to a value of Ψ S ≈ −2.4 MPa.

Laboratory and field bioassays on the effects of Beauveria bassiana Vuillemin (Hypocreales: Cordycipitaceae) on red oak borer, Enaphalodes rufulus (Haldeman) (Coleoptera: Cerambycidae)

An unexpected outbreak of a native longhorned beetle, the red oak borer (Enaphalodes rufulus (Haldeman)), occurred in upland oak forests of Arkansas, Missouri and Oklahoma ca. 1999–2005. Few management tools exist for reducing E. rufulus populations. Laboratory bioassays were conducted to determine susceptibility of all E. rufulus life stages to the fungal pathogen Beauveria bassiana Vuillemin. Egg, neonate, early-instar, pupal, and adult stages of E. rufulus were all susceptible to a natural isolate of B. bassiana collected from E. rufulus (ARSEF 7404) or a commercial B. bassiana product, BotaniGard®. In July 2003, 10 living, E. rufulus-infested northern red oak (Quercus rubra L.) boles were sprayed with a 2 L BotaniGard®B. bassiana suspension of 1.3×1011 viable conidia per 2m of each bole at a forested site in the Ozark National Forest, Franklin County, Arkansas. The following spring, trees were removed and sampled for E. rufulus larvae that had survived or died during the winter. Live E. rufulus larval density in untreated Q. rubra log samples was significantly greater than in treated log samples with means of 16.4±1.8 (SE) and 4.4±2.0 larvae per m2 of bark for untreated and treated logs, respectively. Application of B. bassiana spray against early-instar E. rufulus would be most effective in mid-summer of odd-numbered years to target vulnerable early E. rufulus life stages and to reduce structural damage to trees caused by E. rufulus feeding.

Juniperus virginiana encroachment into upland oak forests alters arbuscular mycorrhizal abundance and litter chemistry

Upland oak forests in the ecotone between the eastern deciduous forest and the southern Great Plains are threatened by encroachment of eastern redcedar (Juniperus virginiana) due to fire suppression. The rapid rate of encroachment caused concern about concomitant alterations of site characteristics including nutrient cycling and the soil microbial communities (SMC) that could lead to positive feedbacks reinforcing eastern redcedar encroachment. We studied eight upland oak forests across central and western Oklahoma with stands representing three levels of encroachment: oak-dominated, eastern redcedar-dominated, and an intermediate mixture of both species. We analyzed litter chemistry (carbon, lignin, and nitrogen), soil chemistry (soil organic matter, NH4N, NO3-N, PO4, K, and pH), and profiled soil microbial communities using phospholipid fatty acid analysis (PLFA). Eastern redcedar encroachment was accompanied by reduced litter carbon along with higher levels of arbuscular mycorrhizal (AM) fungi while litter N was lower in mixed stands. However, we detected no change in soil chemistry. Our results indicate eastern redcedar encroachment in these upland oak forests reduced litter quality and altered the SMC through increases in AM fungi, a symbiont associated with eastern redcedar. These alterations may create positive soil–microbial feedbacks by reducing the fitness of the dominant oak species and facilitating rapid increase in eastern redcedar in this threatened, oak-dominated ecosystem.

Effect of long-term understory prescribed burning on standing and down dead woody material in dry upland oak forests

Dead woody material, long ignored or viewed as a nuisance for forest management, has gained appreciation for its many roles in the forest including wildlife habitat, nutrient storage and cycling, energy for trophic webs, protection of soil, fuel for fire and carbon storage. The growing interest in managing dead woody material has created strong demand for greater understanding of factors controlling amounts and turnover. Prescribed burning, an important management tool, may have strong effects of dead woody material given fire’s capacity to create and consume dead woody material. We determined effects of long-term understory prescribed burning on standing and down woody material in upland oak forests in south-central North America. We hypothesized that as frequency of fire increased in these stands the amount of deadwood would decrease and the fine woody material would decrease more rapidly than coarse woody material. The study was conducted in forests dominated by post oak (Quercus stellata) and blackjack oak (Quercus marilandica) in wildlife management areas where understory prescribed burning had been practiced for over 20years and the range of burn frequencies was 0 (unburned) fires per decade (FPD) to 4.6 FPD. The amount of deadwood was low compared with more productive forests in southeastern North America. The biomass (24.7Mgha−1) and carbon stocks (11.7Mgha−1) were distributed among standing dead (22%), coarse woody debris (CWD, dia.>7.5cm., 12%), fine woody debris (FWD, dia.⩽7.5cm., 23%), and forest floor (43%). There was no evidence that understory prescribed burning influenced the amount and size distribution of standing and down dead woody material. There were two explanations for the lack of a detectable effect. First, a high incidence of severe weather including ice storms and strong winds that produce large amounts of deadwood intermittently in an irregular pattern across the landscape may preclude detecting a strong effect of understory prescribed burning. Second, fire suppression during the first one-half of the 20th Century may have led to encroachment of woody plants into forest gaps and savannas creating a patchwork of young and old stands that produced deadwood of different sizes and at different rates.