Central Hardwood Forest Research Articles

Impacts of Short-Rotation Early-Growing Season Prescribed Fire on a Ground Nesting Bird in the Central Hardwoods Region of North America.

Landscape-scale short-rotation early-growing season prescribed fire, hereafter prescribed fire, in upland hardwood forests represents a recent shift in management strategies across eastern upland forests. Not only does this strategy depart from dormant season to growing season prescriptions, but the strategy also moves from stand-scale to landscape-scale implementation (>1,000 ha). This being so, agencies are making considerable commitments in terms of time and resources to this management strategy, but the effects on wildlife in upland forests, especially those dominated by hardwood canopy species, are relatively unknown. We initiated our study to assess whether this management strategy affects eastern wild turkey reproductive ecology on the Ozark-St. Francis National Forest. We marked 67 wild turkey hens with Global Positioning System (GPS) Platform Transmitting Terminals in 2012 and 2013 to document exposure to prescribed fire, and estimate daily nest survival, nest success, and nest-site selection. We estimated these reproductive parameters in forest units managed with prescribed fire (treated) and units absent of prescribed fire (untreated). Of 60 initial nest attempts monitored, none were destroyed or exposed to prescribed fire because a majority of fires occurred early than a majority of the nesting activity. We found nest success was greater in untreated units than treated units (36.4% versus 14.6%). We did not find any habitat characteristic differences between successful and unsuccessful nest-sites. We found that nest-site selection criteria differed between treated and untreated units. Visual concealment and woody ground cover were common selection criteria in both treated and untreated units. However, in treated units wild turkey selected nest-sites with fewer small shrubs (<5 cm ground diameter) and large trees (>20 cm DBH) but not in untreated units. In untreated units wild turkey selected nest-sites with more large shrubs (≥5cm ground diameter) but did not select for small shrubs or large trees. Our findings suggest that wild turkey have not benefited from the reintroduction of prescribed fire to the WRERA.

Importance of succession, harvest, and climate change in determining future composition in U.S. Central Hardwood Forests

Most temperate forests in U.S. are recovering from heavy exploitation and are in intermediate successional stages where partial tree harvest is the primary disturbance. Changes in regional forest composition in response to climate change are often predicted for plant functional types using biophysical process models. These models usually simplify the simulation of succession and harvest and may not consider important species‐specific demographic processes driving forests changes. We determined the relative importance of succession, harvest, and climate change to forest composition changes in a 125‐million ha area of the Central Hardwood Forest Region of U.S. We used a forest landscape modeling approach to project changes in density and basal area of 23 tree species due to succession, harvest, and four climate scenarios from 2000 to 2300. On average, succession, harvest, and climate change explained 78, 17, and 1% of the variation in species importance values (IV) at 2050, respectively, but their contribution changed to 46, 26, and 20% by 2300. Climate change led to substantial increases in the importance of red maple and southern species (e.g., yellow‐poplar) and decreases in northern species (e.g., sugar maple) and most of widely distributed species (e.g., white oak). Harvest interacted with climate change and accelerated changes in some species (e.g., increasing southern red oak and decreasing American beech) while ameliorated the changes for others (e.g., increasing red maple and decreasing white ash). Succession was the primary driver of forest composition change over the next 300 years. The effects of harvest on composition were more important than climate change in the short term but climate change became more important than harvest in the long term. Our results show that it is important to model species‐specific responses when predicting changes in forest composition and structure in response to succession, harvest, and climate change.

Are more complex physiological models of forest ecosystems better choices for plot and regional predictions?

Process-based forest ecosystem models vary from simple physiological, complex physiological, to hybrid empirical-physiological models. Previous studies indicate that complex models provide the best prediction at plot scale with a temporal extent of less than 10 years, however, it is largely untested as to whether complex models outperform the other two types of models at plot and regional scale in longer timeframe (i.e. decades). We compared model predictions of aboveground carbon by one representative model of each model type (PnET-II, ED2 and LINKAGES v2.2, respectively) with field data (19–77 years) at both scales in the Central Hardwood Forests of the United States. At plot scale, predictions by complex physiological model were the most concordant with field data, suggesting that physiological processes are more influential than forest composition and structure. Hybrid model provided the best predictions at regional scale, suggesting that forest composition and structure may be more influential than physiological processes.

Landscape- and regional-scale shifts in forest composition under climate change in the Central Hardwood Region of the United States

Context Tree species distribution and abundance are affected by forces operating at multiple scales. Niche and biophysical process models have been commonly used to predict climate change effects at regional scales, however, these models have limited capability to include site-scale population dynamics and landscape-scale disturbance and dispersal. We applied a landscape modeling approach that incorporated three levels of spatial hierarchy (pixel, landtype, and ecological subsection) to model regional-scale shifts in forest composition under climate change.

Potential host and range expansion of an exotic insect-pathogen complex: Simulating effects of sassafras mortality from laurel wilt disease invasion in the central hardwoods region1

Potential host and range expansion of an exotic insect-pathogen complex: Simulating effects of sassafras mortality from laurel wilt disease invasion in the central hardwoods region¹

Potential host and range expansion of an exotic insect-pathogen complex: Simulating effects of sassafras mortality from laurel wilt disease invasion in the central hardwoods region1

Abstract Laurel wilt disease is altering forests of the southeastern USA with widespread mortality to lauraceaous hosts, such as redbay (Persea borbonia (L.) Spreng.) and sassafras (Sassafras albidum (Nutt.) Nees). Sassafras is broadly distributed throughout the eastern USA and could serve as a pathway for laurel wilt disease spread into deciduous forests. The resulting invasion and widespread mortality of sassafras would affect these forests ecologically. In anticipation of this, we used preexisting vegetation data and the Forest Vegetation Simulator to predict future characteristics of invaded and noninvaded forests under two sassafras mortality scenarios, 33% and 99%. We calculated changes in total basal area and basal area of dominant species to assess the effects of invasion on forests of central Kentucky. We found that simulated sassafras mortality immediately resulted in significant declines to total basal area (0.87–2.32 m2/ha reductions) and also affected basal areas of selected species over time...

Raccoon Spatial Requirements and Multi-Scale Habitat Selection within an Intensively Managed Central Appalachian Forest

Abstract We studied a raccoon (Procyon lotor) population within a managed central Appalachian hardwood forest in West Virginia to investigate the effects of intensive forest management on raccoon spatial requirements and habitat selection. Raccoon home-range (95% utilization distribution) and core-area (50% utilization distribution) size differed between sexes with males maintaining larger (2×) home ranges and core areas than females. Home-range and core-area size did not differ between seasons for either sex. We used compositional analysis to quantify raccoon selection of six different habitat types at multiple spatial scales. Raccoons selected riparian corridors (riparian management zones [RMZ]) and intact forests (> 70 y old) at the core-area spatial scale. RMZs likely were used by raccoons because they provided abundant denning resources (i.e., large-diameter trees) as well as access to water. Habitat composition associated with raccoon foraging locations indicated selection for intact forests, ripari...

Economic and Life-Cycle Analysis of Forest Carbon Sequestration and Wood-Based Bioenergy Offsets in the Central Hardwood Forest Region of United States

This study investigates the combined impact of carbon and bioenergy markets on upland oak dominated mixed hardwood forests in the Central Hardwood Forest Region (CHFR) of the United States. A modification of the Hartman model was used for the economic analysis of carbon sequestration and using wood-based biomass for bioenergy. A life-cycle assessment was used to determine the amount of carbon sequestered due to stand growth and emitted during harvesting and decay of wood products. Two scenarios were taken, one where additionality of carbon is considered and the other where it is not. Sensitivity analysis was done with the range of carbon and bioenergy prices. The results show that net carbon payments have more impact on land expectation value (LEV) when additionality is not considered; in contrast, bioenergy payments have more impact on LEV when additionality is considered. Carbon and bioenergy prices also influenced the amount of stand level supply of forest products and carbon in both scenarios. In general, sawtimber, wood bioenergy, and carbon supply increased with an increase in carbon prices, whereas, pulpwood supply decreased. With few exceptions at higher carbon prices, bioenergy supply decreased with the increase in wood bioenergy prices, showing a backward bending supply curve in both scenarios.

Facilitating Oak and Hickory Regeneration in Mature Central Hardwood Forests

Advanced oak and hickory regeneration is often absent in mature oak-hickory forests in the Central Hardwood Region of the United States. Prescribed fire and thinning, alone and combined, are commonly prescribed silvicultural treatments that are recommended to initiate the regeneration process. This study examined the regeneration response in three mature oak stands following four treatments: (1) thin, (2) burn, (3) thinning and burning, or (4) no treatment (control). Ten years after initial treatment, results indicate that oak and hickory seedlings had greater height and diameter in the thinning and burning treatment compared to the control and that this treatment may help facilitate desirable regeneration in mature oak-hickory forests.

Changes in Small Mammal Microhabitat Use Following Silvicultural Disturbance

Abstract Silvicultural disturbance can lead to major shifts in biotic and abiotic characteristics of forests, with significant implications for wildlife. Many studies have demonstrated site occupancy and abundance of small mammals changes following silviculture, but few have identified the habitat characteristics associated with small mammal responses. We conducted a study in the central hardwood forest region of the U.S. to examine the relationship between small mammal habitat use and habitat variables at the microsite scale, before and after silvicultural disturbance, while explicitly accounting for imperfect detection. Following the creation of harvest openings, vegetation cover and coarse woody debris increased, and leaf litter depth decreased. Fewer changes occurred following the midstory removal stage of a shelterwood harvest. Eastern chipmunks (Tamias striatus) and white-footed mice (Peromyscus leucopus) were positively correlated with woody vegetation cover and coarse woody debris, and short-taile...

Effects of abundant white-tailed deer on vegetation, animals, mycorrhizal fungi, and soils

The last several decades have seen dramatic increases in ungulate populations worldwide, and white-tailed deer in the eastern United States currently exist at unprecedented densities in many areas. Numerous studies have demonstrated the effects of high densities of white-tailed deer on forest communities. However, few studies have simultaneously examined the effects of deer on multiple components of forest communities across trophic levels. Here, we simultaneously examine effects of excluding white-tailed deer on responses of woody and herbaceous vegetation, terrestrial and subterranean animals, mycorrhizal fungi, and soil characteristics. This study was conducted in a forest preserve with high deer densities in the central hardwoods region of the Midwestern US, using a series of replicated deer exclosures (15×15m) and adjacent unfenced controls that ranged in age from two to seven years. Despite significant tree recruitment inside exclosures, we recorded no native tree seedling recruitment in control plots. In addition, the growth rate of existing tree seedlings was significantly greater in exclosures than in controls, and the growth rate of invasive shrubs was approximately 30 times higher inside exclosures. Exclosures also had increased height, species diversity, and abundance of spring plants, and increased vegetation density in summer. We also found differences in terrestrial animals with higher densities of white-footed mice (Peromyscus leucopus) and dog ticks (Dermacentor variabilis) inside deer exclosures. However, there were no differences in salamanders or earthworms. Soil inside exclosures was significantly less compacted than in control plots despite the short period of deer exclusion, but there were no significant differences in soil nutrients or arbuscular mycorrhizal fungi. These results indicate that there are strong effects of high deer densities on all classes of understory vegetation and indirect effects on animals and soils. However, most belowground effects were nonsignificant, suggesting that responses of belowground communities to deer exclusion are weaker or slower to develop than aboveground effects.

Effects of silvicultural disturbance on acorn infestation and removal

Oak (Quercus spp.) regeneration is an important forest management goal in the central hardwood forest region of the United States. Silvicultural methods that target oak regeneration, such as the creation of canopy openings and removal of shade-tolerant midstory trees, are complicated by the impact of pre- and post-dispersal predators of oak acorns like acorn weevils (Curculio spp.) and granivorous small mammals. Understanding the effects of forest disturbance created by silviculture on these predators is important to promote successful oak regeneration. We conducted a 6-year study of acorn production, weevil infestation, and acorn removal at 113 black (Q. velutina) and white oak (Q. alba) trees impacted by three types of silvicultural treatments: adjacent to harvest openings, midstory removal (first-stage shelterwood harvest), and control (no harvest) in south-central Indiana, USA. We observed highly variable acorn production across years, but minimal impact of silvicultural treatments. Levels of weevil infestation and acorn removal by small mammal seed predators also varied greatly, and predation pressure was highest in years when acorns were scarce. Weevil infestation was reduced following midstory removal in shelterwood harvests, but probability of acorn removal by small mammals was unchanged following harvest. Damaged, germinated, and weevil-infested acorns were less likely to be removed by seed predators, suggesting additive effects of pre- and post-dispersal predators. This study emphasizes the importance of considering acorn predators in oak regeneration silviculture, and timing harvests to follow large acorn crops in order to reduce predation pressure and generate a high number of seedlings.

LANDIS PRO: a landscape model that predicts forest composition and structure changes at regional scales

LANDIS PRO predicts forest composition and structure changes incorporating species‐, stand‐, and landscape‐scales processes at regional scales. Species‐scale processes include tree growth, establishment, and mortality. Stand‐scale processes contain density‐ and size‐related resource competition that regulates self‐thinning and seedling establishment. Landscape‐scale processes include seed dispersal and disturbances. LANDIS PRO is designed to be compatible with forest inventory data, thus extensive inventory data can be directly utilized to initialize and calibrate model parameters before predicting future forest changes. LANDIS PRO allows for exploring the effects of disturbances, management, climate change, and modeling the spread of invasive species. We demonstrate that LANDIS PRO successfully predicts forest successional trajectories and stand development patterns in the Central Hardwood Forest region in U.S.

Financial and Management Implications of Producing Bioenergy in Upland Oak Stands in Kentucky

Wood-based bioenergy or energywood has been suggested as an alternative to various fossil-fuel-based energy sources. While a variety of studies have investigated some economic aspects of forest-based bioenergy throughout the United States, none have yet examined the profitability of forest-based bioenergy from a landowner perspective in the Central Hardwood Forest Region. This study assesses how a forest-based bioenergy market would impact the optimal rotation age, the mix of forest products produced, and the potential financial return from typical mixed hardwood nonindustrial private forest (NIPF) lands in Kentucky. Results indicate that producing woody biomass for energy alongside other traditional forest products substantially decreases rotation age and increases the financial returns to the landowner. The reduction in rotation age is substantial enough that there could be fairly large changes in the product mix obtained from a typical mixed hardwood stand in the region. This result indicates that policies aimed at regulating the forest-based bioenergy market should take the potential for significant changes in forest management into account.

Soil richness and endemism across an environmental transition zone in Wisconsin, USA

Soil richness was examined across the Wisconsin ecological tension zone, which constitutes a transition between the central hardwood forest and prairie biomes to the south and the northern mixed hardwood and conifer forest biome to the north. There were greater numbers (normalized by county area) of soil orders, suborders, and great groups in counties within the transition zone than in those outside the zone. A zone of soils containing glossic horizons extends 75km to the north of the Wisconsin transition zone separates Alfisols (dominantly Hapludalfs) and Mollisols in the south from Spodosols and Glossudalfs in the north; this zone may represent the mid-Holocene position of the tension zone. Soil endemism is a concept whereby soils are restricted to a limited geographic area based on a unique set of soil-forming factors. In this study, endemic soils were identified on the basis of having a centralized distribution, lacking competing soil series, and being unique to Wisconsin and adjoining states. Although the transition zone contains 13% of the state's area, it has 40% of the endemic soils. Endemic soils in Wisconsin occur in 7 orders, 14 suborders, 29 great groups, 83 subgroups, and 138 families; they include 159 soil series that cover 1.44millionha (19% of state land area). The predominant soil properties related to soil endemism include (i) the presence of a glossic horizon (34% of endemic soils), (ii) aquic conditions or oxyaquic subgroups (28%), and (iii) bisequal profiles (20%). There are 102 vascular plant species endemic to Wisconsin, the distribution of which appears to be related more to the landform than to soil taxa.

Results of 20 years of experimental forest management on breeding birds in Ozark forests of Missouri, USA

Understanding the relationship between forest management and bird populations requires understanding the effects of silvicultural practices on avian demography at large spatio-temporal scales. The Missouri Ozark Forest Ecosystem Project (MOFEP) is a long-term, large-scale manipulative experiment testing the effects of even-aged (3–13ha cuts over 10–15% of the site; n=3), uneven-aged (0.03–3.14ha cuts over 57% of the site; n=3), and no harvest forest management on ecosystem level responses. We report on the effects of these management systems on the density and reproductive success of 11 songbird species from 5years of pre-harvest (1991–1995) to 14years of post-harvest (1997–2010). Density of four of the five mature forest species were lower after harvest in all management types and did not return to pre-harvest density, even in no harvest sites. Ovenbird (Seiurus aurocapilla) and Wood Thrush (Hylocichla mustelina) responded most negatively to even-aged management in the early post-harvest period (1997–2003) where density was significantly lower than in no harvest sites. Kentucky Warbler (Geothlypis formosa) density increased on uneven-aged and even-aged sites during early post-harvest, but returned to pre-harvest density on both management types by 14years post-harvest. Acadian Flycatcher (Empidonax virescens) and Worm-eating Warbler (Helmitheros vermivorus) had lower density in all treatments post-harvest. Among the six early-successional species, density of Blue-winged Warbler (Vermivora cyanoptera), Hooded Warbler (Setophaga citrina), Indigo Bunting (Passerina cyanea) White-eyed Vireo (Vireo griseus) and Yellow-breasted Chat (Icteria virens) were significantly higher in even-aged and uneven-aged sites than in no harvest sites after harvest. Density of Prairie Warbler (Setophaga discolor) were significantly higher only in even-aged management after harvest. Prairie Warbler, Hooded Warbler, and White-eyed vireo appeared on the study sites following harvest while Indigo Bunting, Prairie Warbler, and Yellow-breasted Chat were absent from the study area 14years post-harvest. Nest survival of mature forest and early-successional species did not change significantly from the pre- to the late post-harvest period or with forest management. Brood parasitism rates remained low from pre-harvest to late post-harvest, but parasitism rates were higher for early-successional species (4%) than mature forest species (1%). Although forest management had variable effects on species, we suggest a modified version of even-aged management could maximize benefits to early-successional species while minimizing decreases in mature forest bird species in central hardwood forests. Rather than the current prescription to harvest 10–15% of the mature stands every 15years, we recommend harvesting approximately half the number of mature stands with a shorter re-entry period of 8–10years.

Simulating stand-level harvest prescriptions across landscapes: LANDIS PRO harvest module design

Forest landscape models (FLMs) are an important tool for assessing the long-term cumulative effects of harvest over large spatial extents. However, they have not been commonly used to guide forest management planning and on-the-ground operations. This is largely because FLMs track relatively simplistic vegetation information such as age cohort presence/absence, forest type, and biomass that are incompatible with tree density and size on which most harvest prescriptions are based. We describe and demonstrate the newly developed harvest module of the LANDIS PRO FLM, which tracks density, size, basal area, and stocking by species age cohorts for each site (cell). With this quantitative information, the module can simulate basal area controlled harvest, stocking-level controlled harvest, and group selection harvest. Through user-specified harvest year (frequency), stand ranking, and species and age preference, the new module can simulate a wide variety of harvest prescriptions such as thinning from above and below, shelterwood, clear-cutting, and group selection. We applied the LANDIS PRO harvest module to a large (17 000 km2) central hardwood forest landscape in Missouri. The simulated harvest prescriptions produced realistic stand-scale results when plotted on Gingrich stocking charts. The harvest module improves on previous versions by allowing partial treatment of individual age-classes within a cell and reporting results in metrics commonly used in stand-scale silviculture. It provides a closer link between landscape-scale simulation methods and stand-scale management.

Short-term responses of small mammals to timber harvest in the United States Central Hardwood Forest Region

Identifying the effect of timber harvest on plant and animal communities is important for managers seeking to conserve ecosystem function. Timber harvest affects many forest species, including small mammals, a key component of forest food webs. We studied short-term responses of several common small-mammal species to clearcutting and shelterwood harvest in hardwood forests of southern Indiana. We trapped small mammals at 32 forest stands for 2 years before harvest. Each stand then received a timber harvest treatment: either the creation of a 0.4-, 2-, or 4-ha clearcut opening, shelterwood harvest, or no harvest. Following harvest, we trapped small mammals for 3 additional years. We estimated abundance from capture data and compared estimates before and after harvests using an N-mixture model fit in a Bayesian framework. Small mammals in our study differed in their responses to timber harvest. Eastern chipmunks (Tamias striatus) increased in all clearcut opening sizes, whereas white-footed mice (Peromyscus leucopus) and short-tailed shrews (Blarina brevicauda) were less abundant in larger clearcuts. The first stage (midstory removal) of a 3-stage shelterwood harvest had no impact on the small-mammal community. Mast production influenced small-mammal populations independent of silvicultural treatments. In the years immediately following harvest, managers can expect populations of common small-mammal species to increase or remain unchanged in small clearcut openings, but some species decline in larger openings that reduce the edge to interior ratio of habitat created. The phased shelterwood harvest system in which habitat is altered over a longer period may be ideal for maintaining existing small-mammal populations. © 2013 The Wildlife Society.

Restoring Riparian Forests in the Missouri Ozarks

Restoring the function of riparian forest ecosystems has become a primary objective of many land management agencies throughout the central hardwood region, and consequently, much emphasis has been placed on planting native hardwood tree species in former bottomland agricultural fields. However, there is little information providing successful restoration techniques in old-field riparian ecosystems, especially in the Ozark highlands ecoregion of Missouri. Objectives of this study were to examine the efficacy of two herbicide and three cover-crop vegetation management treatments on the (1) composition and density of competing vegetation, (2) survival and height growth of planted seedlings of 13 native bottomland tree species, and (3) the density and composition of natural reproduction colonizing three old-field riparian sites in the Missouri Ozarks. Overall, we found selection of tree species was a more important determinant of afforestation success (i.e., high survival and height growth) than the type of vegetation management used during establishment. Planting bareroot stock is an important strategy for establishing hardmast species because there is little evidence that they will colonize naturally very quickly following abandonment of tall fescue pastures in Ozark bottomlands.

Components and Nutrient Concentrations of Small-Diameter Woody Biomass for Energy

The growing interest in using woody biomass for energy offers a potential opportunity to commercially remove cohorts of small-diameter trees (
<25 cm dbh) during thinning operations that otherwise have little or no economic value. However, there is little information about the quantity of biomass and the nutrients that would be removed during small-diameter harvests in oak stands of the Central Hardwood Region. The objectives of the study were to quantify biomass removals by component (foliage, twigs, bark, and stemwood) and the nutrient concentrations within components for estimating quantities of both wood and nutrients that would be removed under alternative harvest prescriptions. White oak was the most common species harvested; others included post oak, black oak, mockernut hickory, American elm, persimmon, white ash, and dogwood. Sampling indicated that heartwood and sapwood comprised most of the biomass (78 -79%) followed by bark (15%), twigs (4 - 5%), and leaves (about 2%). Estimated nutrient removals during a small-diameter harvest in this region were 1.3-3 times greater than during conventional sawlog harvests. The relatively high nutrient removals that can occur for biomass harvesting compared to traditional sawlog harvests underscore an ongoing need to ensure that nutrient removals during biomass harvesting do not exceed inputs from soil mineral weathering and the atmosphere.