Forests dominated by loblolly pine (Pinus taeda) are presently the most extensive vegetation type in the Southeastern United States, encompassing a wide range of climate, soils, and topography. Loblolly pine was also widespread prior to the arrival of Europeans, but was probably limited to a much narrow range of habitats. A history of intensive agricultural land use and land abandonment, combined with intensifying forest management and changes in the historical fire regime, led to the rapid expansion of loblolly pine forests throughout the 20^th century.

Loblolly pine colonizes former agricultural fields within a decade of their abandonment if a sufficient seed source is available. These old-field stands are dominated by loblolly pine for the first several decades of forest succession. Eventually, a cohort of hardwoods establishes in the forest understory and gradually increases in dominance as the overstory pines die. Successional pathways following timber harvesting or natural disturbance often are more complex, because hardwoods establish as seedlings or sprouts along with the initial pine cohort.

Fire alters pathways of forest succession by causing mortality of existing trees, and by facilitating the establishment of new trees. Although loblolly pine seedlings and saplings are vulnerable to girdling and crown scorch, larger trees can survive most low-intensity surface fires. The establishment of loblolly pine seedlings is facilitated by high-intensity fires that kill overstory trees, expose mineral soil, and allow light to reach the forest floor. Hardwood seedlings and saplings are also susceptible to fire mortality, but can resprout vigorously from stumps and buried rootstocks. Depending on the season and frequency of burning, fires can either increase or decrease hardwood density in the forest understory. Fire can also affect forest health by influencing the susceptibility of loblolly pine to insects and disease.

Fire influences soils as well as aboveground components of the forest ecosystem. Although nitrogen and other nutrients are released to the atmosphere as gasses and particulates, the losses resulting from low-intensity surface fires typically do not lead to reductions in site productivity. Similarly low-intensity fires typically leave a layer of unburned organic matter that protects the mineral soil from post-fire erosion.

In the modern landscape, prescribed fire is commonly used as a management tool in loblolly pine forests, whereas large wildfires are comparatively rare. Prescribed burning is frequently applied as a fuel-reduction treatment to reduce the risk of catastrophic wildfire, and is particularly effective at reducing fine fuel loads. Fire can also be used in timber management for site preparation, to reduce hardwood competition, and to thin dense stands of young pine.

Because fire affects the structure and species composition of understory vegetation in loblolly pine forests, it also has a strong influence on the wildlife species that utilize these forests as habitat. Annual burning produces abundant herbs and grasses, providing food for a variety of birds and mammals. Burning at longer intervals can be effective for maintaining mast-producing trees and shrubs in the understory. The open, savannah-like forest structure produced by frequent fires is critical habitat for several threatened and endangered species such as the red-cockaded woodpecker (Picoides borealis), gopher tortoise (Gopherus polyphemus), and indigo snake (Drymarchon corais).

Ecosystem Distribution and Extent

The range of loblolly pine encompasses the Southern Mixed Forest and Outer Coastal Plain Mixed Forest provinces defined by (Bailey 1995). Loblolly pine occurs mainly in the southern Piedmont and Coastal Plain physiographic sections from East Texas to Virginia, but is also found at the southern extremities of the Ridge and Valley, and Cumberland Plateau sections of the Appalachian Highlands province (Eyre 1980). It does not grow in the Mississippi River valley which forms a barrier of 30 to 200 km between the western and eastern populations. There are currently more than 19.8 million hectares (49 million acres) of loblolly pine forest in the 13 southern states. Of the (1,952 million m³) (68,918 million ft³) of loblolly-shortleaf pine timber volume, 75% occurs in naturally regenerated stands and 25% occurs in plantations (Conner and Hartsell 2002). In contrast to this widespread distribution in the modern landscape, loblolly pine was probably limited to wetter sites that burned infrequently in presettlement forests. The arrival of Europeans precipitated a series of major land use changes, which in turn fostered a significant expansion of loblolly pine across the region. Today, loblolly pine is the most important timber species in the United States, and loblolly pine forests provide a variety of ecosystem services including wildlife habitat, watershed protection, and carbon storage (Schultz 1997). Fire was historically an important ecological process in these forests, and prescribed burning is still widely used for silvicultural purposes, habitat enhancement, and fuel reduction.

Environment

Climate

Climate within the range of loblolly pine is humid with long hot summers and mild winters. Rainfall is evenly distributed throughout the year, but heavy downpours and summer droughts are common (Peterson 2002). Tropical air masses originating over the Gulf of Mexico and South Atlantic produce more moderate temperatures and higher rainfall along the coast than in the interior. Growth of loblolly pine is impaired by late spring frosts near the northern edge of its range, and by inadequate rainfall during the growing season at its westernmost extent (Baker and Langdon 1990).

Average annual temperatures in the outer Coastal Plain vary from 16° C (61° F) in Virginia to 21° C (70° F) in north Florida (Bailey 1995). Forests benefit from a long growing season in this climate, with frost-free periods ranging 200 days in Virginia to 300 days along the Gulf Coast (Hunt 1967). Precipitation ranges from 102 cm (40 inches) per year at the western extent of loblolly pine in Texas to 153 cm (60 inches) per year in Florida (Bailey 1995), and is generally lowest in fall and highest in summer when convective thunderstorms develop (Peterson 2002). Thunderstorms typically occur 80-130 days annually in Florida and 80-100 days annually on the Gulf Coastal Plain (White et al. 1998). Coastal areas are also subject to hurricanes that impact forests through high winds that topple trees, and heavy rains that can cause severe flooding. Hurricane season extends from late summer into fall, and at least 2 hurricanes per year have reached the southeastern US over most of the past 50 years (Myers and Van Lear 1998).

The interior portions of the loblolly pine range are slightly cooler, with average annual temperatures ranging from 14° (57° F) to 18° (64° F) C in the Piedmont section, and 13° (55° F) to 16° (61° F) C in the Southern Ridge and Valley section (McNab and Avers 1994). However, there are still typically more than 200 frost-free days per year in the Piedmont, (Hunt 1967), with a growing season typically lasting from 205-235 days (Bailey 1995). Annual precipitation ranges from 112 to 140 cm (44 to 55 inches) in the Piedmont section and 90-140 cm (35 to 55 inches) in the Southern Ridge and Valley section (McNab and Avers 1994). The frequency of thunderstorms generally decreases along a gradient from coastal to inland areas, declining to as low as 40-60 days annually in Kentucky and other interior regions (White et al. 1998). Although inland forests are often impacted by hurricanes, wind speeds are typically lower and disturbance severity is generally less than in coastal areas.

Terrain

Loblolly pine occurs over a broad elevation gradient ranging from sea level to nearly 900 m (2,953 feet) in northern Alabama and Georgia. Across this range, loblolly pine is found in a variety of landforms. Approximately 36% of its range is lowlands or smooth plains, 49% irregular or rolling plains and 15% is hilly or mountainous land (Schultz 1997).

The Coastal Plains are predominantly comprised of flat, weakly dissected alluvial plains. Elevations range from sea level to 150 m (492 feet), with local relief usually less than 35 m (115 feet) on the Gulf Coastal Plain and 15 m (49 feet) on the Atlantic Coastal plain (Ware et al. 1993). Despite the low relief of the Coastal Plain, relatively small changes in elevation can result in large shifts in soil moisture and associated vegetation.

The Piedmont is characterized by rolling hills, with elevations ranging from 100 m (328 feet) along the fall line bordering the Coastal Plain to 550 m (1804 feet) in the Appalachian foothills (McNab and Avers 1994). Terrain is moderately dissected and characterized by narrow to broad upland ridges, short hillslopes, and narrow valley floors. Local relief typically varies from 30 to 90 m (98 to 295 feet). Slope position and exposure to solar radiation influence soil moisture and the distribution of major tree species (Cowell 1995).

The Southern Cumberland Plateau and Southern Ridge and Valley are highly dissected landscapes, occurring at elevations of 100 to 400 m (328 to 1,312 feet) (McNab and Avers 1994). Both consist primarily of plains with hills or open high hills. Local relief ranges from 90 to 150 m (295 to 492 feet) in both sections. Because of the greater variability in terrain, topographic constraints have an even greater influence on local environment and forest community composition than in the Piedmont (Bolstad et al. 1998).

Soils

Settlers originally applied the term “loblolly” to moist depressions and swamps, and loblolly pines were historically associated with these mesic soils (Wahlenberg 1960). However, loblolly pine can grow successfully on a much wider range of sites in the absence of fire and competition from other species. In the modern landscape, loblolly pine can be found on a variety of soils ranging from flat, poorly drained Spodosols in the lower Coastal Plain to the well-drained Ultisols in the rolling Piedmont and Plateau.

Most soils of the Atlantic Coastal Plain and the Piedmont are Ultisols, which underlie about three-quarters of the Southeast (Skeen et al. 1993). Ultisols are mineral soils derived from a variety of parent materials and are characterized by sandy or loamy surface horizons and loamy or clayey subsurface horizons. Udults and Aqults are the principal suborders. Udults are well-drained, humus-poor and are yellowish brown or red in color. Aqults are saturated at some point during the year and typically have gray or olive colored subsoils. The remaining soils are Alfisols (11%), Entisols (7%) and Spodosols (3%) with about 1% each in the remaining soil orders (Schultz 1997). Most of the well drained Ultisols and Alfisols are now in agricultural use and the wetter areas of these soils are being drained for crop production (Skeen et al. 1993).

Major Species

Loblolly Pine

Loblolly pine is a medium to large tree averaging 27 to 34 m (89 to 112 feet) in height and 61 to 76 cm (24 to 30 inches) in diameter when it is between 80 and 100 years old on average sites (Baker and Langdon 1990). When fully developed, loblolly is the tallest of the southern pines, reaching a record height of 55.5 m (182 feet). Although individual trees may survive for up to 300 years, most of the original cohort from an even-aged pine stand will have been replaced by hardwoods within 175 years (Schultz 1997).

Juvenile loblolly pine is moderately shade tolerant, but trees become more shade intolerant with age. Because of their shade-tolerance, seedlings and saplings can successfully compete with herbaceous annuals, shrubs, and early-successional hardwoods (Bormann 1953), Mature trees typically achieve maximum growth when 50% or more of the live crown is exposed to direct sunlight (Schultz 1997). Shade tolerance of loblolly pine is similar to that of shortleaf and Virginia pine, lower than that of most hardwoods and greater than slash and longleaf pine (Wahlenberg 1960, Eyre 1980).

Prior to European settlement and the accompanying land use changes, loblolly was associated with wet areas that were not subjected to long periods of flooding or frequent fire. These sites were typically found in major river bottoms, along stream margins, or at wetland edges (Schultz 1997, Hardin et al. 2001). With the exclusion of fire from much of the Southeast, loblolly has proven very successful on an enormous variety of site conditions. Loblolly pines can develop a taproot up to 3 meters (9.8 feet) long in sandy soils, whereas taproots are much shorter on moist sites or in heavy clay soils (Peterson 2002). Sensitivity to moisture stress varies regionally, with individuals in the western portion of the range more drought resistant than those in the east (Fowells 1965). Best growth is on moderately acidic soils with moderate to poor surface drainage, a thick medium textured surface layer and fine textured subsoil. These soil types are commonly found in the uplands of the Atlantic coastal plain and on flood plains of rivers and streams. Poor performance is on shallow or eroded soils or very wet sites. Deep, excessively drained sands are low in quality unless a water table is within reach of the potential growth of roots (Baker and Langdon 1990).

Associated pines

Shortleaf pine (Pinus echinata) is a frequent associate of loblolly pine, but tends to be more competitive on drier sites and at higher elevations. It has a more northern and western range than loblolly pine and hence increases in importance on the upper Piedmont (Baker and Langdon 1990). Slash pine (Pinus elliottii) occurs on much of the coastal plain and was historically confined to mesic sites similar to those occupied by loblolly pine. Like loblolly pine, slash pine has expanded its range in the modern landscape though invasion of cutover areas and abandoned agricultural lands. Pond pine (Pinus serotina), pitch pine (Pinus rigida) and Virginia pine (Pinus virginiana) are also common associates where their ranges overlap that of loblolly pine (Wade et al. 2000).

Major hardwoods

Throughout its range, loblolly pine is often found in mixed stands with a variety of hardwood species. Even when pines comprise the majority of stand basal area, the structure and species composition of the hardwood community may have a major influence on the understory environment, forest succession, and wildlife habitat quality. Common associates found throughout most of the range of loblolly pine include southern red oak (Quercus falcata), northern red oak (Quercus rubra), white oak (Quercus alba), post oak (Quercus stellata), water oak (Q. nigra), pignut hickory (Carya glabra), mockernut hickory (Carya tomentosa), red maple (Acer rubrum), blackgum (Nyssa sylvatica), sassafrass (Sassafras albidum), sweetgum (Liquidambar styraciflua), and persimmon (Diospyros virginiana) (Quarterman and Keever 1962, Cowell 1993, Bragg 2004). In addition, laurel oak (Quercus hemisphaerica), American beech (Fagus grandifolia), southern magnolia (Magnolia grandiflora), and sweetbay (Magnolia virginiana) are often found in association with loblolly pine in the Coastal Plain (Quarterman and Keever 1962, Delcourt and Delcourt 1974, Marks and Harcombe 1981).

Understory vegetation

Although understory vegetation accounts for only a small portion of total forest biomass, it is central to the fire ecology and management of loblolly pine forests. Grasses, forbs, and shrubs provide much of the fuel that affects the behavior and severity of surface fires. Furthermore, the application of prescribed fire is often aimed at manipulating understory vegetation to reduce wildfire risk, enhance wildlife habitat, or reduce competition with crop trees.

Pioneering grasses and forbs establish along with loblolly pine seedlings following agricultural abandonment or timber harvest. Typical early-successional herbs include broomsedge (Andropogon virginicus), ragweed (Ambrosia artemisifolia), crabgrass (Digitaria sanguinalis), and heath aster (Aster ericoides) (Schultz 1997). Composites, grasses, and other pioneer species are also found in mature pine forests that have been recently burned (Cain et al. 1998).

Common understory trees and shrubs occurring throughout the range of loblolly pine include flowering dogwood (Cornus florida), American holly (Ilex opaca), hawthorn (Crataegeus spp.), blueberry (Vaccinium spp.), beautyberry (Callicarpa americana), and viburnum (Viburnum spp.). Pawpaw (Asimina triloba), Wax myrtle (Myrica cerifera), inkberry (Ilex glabra), and yaupon (Ilex vomitoria) are also important in the Coastal Plain. Common species of woody vines include greenbriers (Smilax spp.), Japanese honeysuckle (Lonicera japonica), Carolina Jessamine (Gelsemium sempervirens), Virginia creeper (Parthenocissus quinquefolia), poison ivy (Rhus toxicodendron) and muscadine grape (Vitis rotundifolia) (Hodgkins 1958).

In the Piedmont, understory herbs are usually sparse and often include bluestems (Andropogon spp.), hairy bedstraw (Galium pilosum), striped wintergreen (Chimaphila maculata), creeping lespedeza (Lespedeza repens), and flowering spurge (Euphorbia corollata) (Wade et al. 2000). The density and diversity of understory herbs is typically greater in Coastal Plain forests, particularly on sites that have never been cultivated. Typical herbs include bluestems, panic grasses (Panicum spp.), spike uniola (Chasmanthium laxum), dogfennel (Eupatorium capillifolium) and lespedeza (Lespedeza spp.) (Lewis and Harshbarger 1976). In the Coastal Plain of Georgia, forests on old field sites were characterized by Canada goldenrod (Solidago canadensis), Japanese honeysuckle, and Canadian horseweed (Conyza canadensis), whereas forests on cutover sites were characterized by twinflower (Dyschoriste oblongifolia), anisescented goldenrod (Solidago odora), wiregrass (Aristida stricta), little bluestem (Schizachyrium scoparium), bracken fern (Pteridium aquilinum), scaleleaf aster (Aster adnatus), wild petunia (Ruellia caroliniensis), and goat’s rue (Tephrosia virginiana) (Hedman et al. 2000). In a unharvested, mature mixed loblolly-shortleaf forest in Texas herbaceous species included panic grasses, chasmanthium (Chasmanthium sessiliflorum), sedges (Carex spp.), downy milkpea (Galactia volubilis), elephant’s foot (Elephantopus tomentosus), goldenrod (Solidago spp), copperleaf (Acalypha spp.), twin-eyed berry (Mitchella repens) and noseburn (Tragia urens) (Stransky et al. 1986).

Natural and Cultural History

Forests of the southeastern United States have changed considerably since the last glaciation as climate has shifted and tree species have migrated. Pollen records from sediment cores indicate that the modern pine-dominated flora of the Coastal Plain dates back at least 5000 years before present (Delcourt 1980, Watts and Stuiver 1980). Research based on 19^th-century land survey records from Georgia (Cowell 1995) and Alabama (Black et al. 2002) have highlighted strong physiographic influences on presettlement forest communities. In the coastal plain, pines were the dominant species and hardwoods comprised only a small percentage of witness trees. In the Piedmont, oaks and hickories were the dominant species, whereas pines comprised only 27% of the witness trees in Georgia and 13% in Alabama. Pine dominance in the Piedmont was highest in the uplands (33% of witness trees) and lowest on floodplains (9% of witness trees) (Cowell 1995). Historical records from DeSoto’s expedition in the mid-16^th Century described a similar shift in vegetation, transitioning from open pine savannahs in the Coastal Plain of north Florida and southern Georgia to hardwood-dominated forest in the Piedmont near the border of Georgia and South Carolina (Hudson 1997).

Shifts in the major pine species also occurred along these gradients. On a journey from Augusta to Savannah in 1773, William Bartram documented changes in vegetation from longleaf pine-dominated grasslands in the upper coastal plain to a mixed forest of loblolly pine, oaks, and other hardwoods in the Piedmont (Harper 1998). In the coastal plain, dominant pine species varied with soil moisture status, with longleaf pine dominant on the drier sites and loblolly largely restricted to more mesic areas near wetlands or streams (Schultz 1997). In the Piedmont, shortleaf pine was the dominant species on drier sites, whereas loblolly pine was associated with more mesic areas. Taken as a whole, this evidence suggests that although loblolly pine was probably a very common species in presettlement forests, it had nowhere near the widespread dominance in forest communities that it does today.

Even before the advent of European settlement, native societies exerted considerable influences on the structure and composition of Southern forests. A study of presettlement forests in Alabama based on witness tree records and archaeological data found that tree species composition varied predictably with distance from native population centers (Foster et al. 2004). Although there is considerable disagreement about the size of native populations, there were probably at a minimum 4 million people in North America before the arrival of Europeans, with at least 400,000 living in the Southeast (Krech 2000). Native Americans utilized fire for a variety of purposes, including land clearing, hunting, warfare, and vegetation management. In the Southeast, native people also practiced shifting agriculture in which small patches of forest were cleared, farmed for several years, and then abandoned once soil fertility was exhausted (Williams 1989, Cowdrey 1996). Over longer time scales, forest landscapes changed as populations centers were established, expanded, declined and were ultimately abandoned. For example, Desoto’s expedition in the 16^th century encountered large settlements with extensive agricultural development, but also passed through areas of uninhabited wilderness that had once supported large native populations (Hudson 1997).

However, it is doubtful that the magnitude of native impacts on the forest came close to the drastic and widespread land use changes that resulted from European settlement in the 19^th century. The rate of land clearing peaked in the 1870’s at 308,000 ha/year (760,000 acres/year) in the Southeast and 371,000 ha/year (916,000 acres/year) in the South-central states (Williams 1989). Land clearing declined gradually throughout the remainder of the 19^th century. Rates of clearing had decreased to 150,000 ha/year (370,000 acres/year) in the Southeast and 235,000 ha/year (580,000 acres/year) in the South-central states by the first decade of the 20^th century. In many cases, lands were cleared, farmed, abandoned, and than cleared and farmed again multiple times.

After 1910, the total area of cleared farmland in the eastern United States began to decline steadily (Hart 1968). In the southeastern United States, much of this abandoned farmland was concentrated in the Piedmont regions of South Carolina, Georgia, and eastern Alabama (Hart 1980). Much of the cropland abandonment in this area can be attributed to loss of cotton as a major cash crop. Cotton farming declined in the Piedmont because of soil erosion resulting from poor farming practices, difficulties in farming associated with small ownerships, and steep slopes that limited the potential for mechanization. Legislation and government programs such as the Clarke-McNary act (1924), the Agricultural Conservation Program (1930), the Cooperative Forest Management Act (1950), and the Conservation Reserve Program (1960) all encouraged landowners to withhold land from agricultural production and plant trees (Williams 1989). The present-day predominance of loblolly pine forests across the southeastern United States is a direct result of this legacy of human disturbance and land use.

See also: A History of People and Fire in the South.

Fire Regimes

Although it is widely agreed that fire was an important element of pre-European forest ecosystems, there is very little data from which to infer historical fire-return intervals in the Southeast. Frost (1995) used information from a variety of sources to develop a map of presettlement fire frequencies across the Southeast. Within the current range of loblolly pine, estimates of fire frequency ranged from 1 to 6 years, with highest frequencies in the Coastal Plain and lower frequencies in the Piedmont. These differences resulted from fewer lightning strikes and from topographic complexity that limited the potential for fire spread. In contrast, (Cowell 1995) estimated that historical fire frequency varied between 10 and 50 years in the Georgia Piedmont, based on the argument that the historical hardwood-dominated forests of this region would have been unlikely to develop under shorter fire frequencies.

These discrepancies emphasize the large degree of uncertainty in our understanding of historical fire regimes in the Southeast. Results of dendroecological studies from other high-frequency, low-severity fire regimes emphasize that presettlement fire regimes were quite variable over both time and space (Heyerdahl et al. 2001, Hessl et al. 2004). Spatial variability in terrain, soil moisture, and dominant plant species would have fostered spatial variability in fire occurrence. Drier sites dominated by pines, grasses, and other pyric vegetation probably burned more frequently than more mesic, hardwood-dominated sites. Long-term fluctuations in climate and native populations, as well as chance events, likewise would have resulted in variable fire return intervals on a given site.

Compared to the presettlement era, wildfires have a relatively minor impact on forests in the modern landscape. Prescribed fire was commonly used throughout the settlement period for land clearing and to maintain pasture for hogs and other livestock (Williams 1989). Uncontrolled fires resulting from lightning or accidental ignitions were also common during this period. Beginning in the 1940’s, however, effective fire prevention and suppression activities greatly reduced the impact of wildfires (Brender 1974). The mean percentage of total forested area burned annually in Georgia between 1997 and 2001 was only 0.1 % for Piedmont counties and 0.2 % for Coastal Plain counties (Georgia Forestry Commission, unpublished data). Instead, prescribed fires now account for the majority of acreage burned in Georgia and across most of the Southeast. During the same 5-year period, the mean percentage of forestland burned each year by prescribed fire was 1.7 % in Piedmont counties and 5.5% in Coastal Plain counties (Georgia Forestry Commission, unpublished data). Rates of prescribed burning are generally higher on public lands than on private lands, and are lower in the densely populated wildland-urban interface than in rural areas (Zhai et al. 2003).

For background information, see: Fire Regimes.

Species Adaptations to Fire

The bark of southern pines is thicker and has better insulating qualities than most hardwood species in the region. Of the southern pines, only longleaf and slash pine have bark with a higher resistance to fire damage than mature loblolly (Hare 1965). However, young loblolly pines have relatively thin bark and are susceptible to girdling by fire until they are approximately two inches in diameter (Wade 1993). An experimental study that utilized a propane-fired backfire simulator similarly found that most trees with a ground diameter greater than 5 cm were resistant to girdling by flames within the normal range of backfire intensities (Greene and Shilling 1987).

Crown scorch can also cause fire-induced mortality. The percentage of crown that is scorched depends on both tree size and flame height (McNab 1977, Waldrop and Van Lear 1984). Prescribed winter burns in a mixed loblolly-shortleaf stand in southeastern Arkansas caused an average of 95% crown scorch for seedlings < 0.9 m (3 feet) in height, 90% crown scorch for seedlings >= 0.9 m (3 feet) in height, and 80% for saplings greater than 1.3 cm (0.5 inches) dbh (Cain and Shelton 2002). However, even severe crown scorch may have little effect on the survival and growth of larger trees. In a 17-year old pine plantation in South Carolina, co-dominant trees that were completely scorched suffered only 20% mortality, whereas intermediate trees suffered 20-30% mortality (Waldrop and Van Lear 1984). No dominant trees died as a result of crown scorch. In a 19-year old naturally regenerated loblolly pine stand in southeastern Louisiana, incidence of severe crown scorch following a winter burn was greatest in dense, lightly thinned plots that had a large number of small trees (Lilieholm and Hu 1987). The only trees that experienced significant fire-induced mortality were in the suppressed crown class.

Unlike most hardwoods and some southern pine species such as shortleaf and longleaf pine, loblolly pine does not resprout from the root collar when it is topkilled by fire. However, widespread establishment of both loblolly and shortleaf pine seedlings often occurs following fires. The combustion of the litter layer facilitates seed germination, and fire-induced overstory mortality leads to higher light levels that favor the rapid growth of young loblolly pine seedlings. Loblolly pine regeneration is greatly enhanced when fire coincides with heavy seed production (Cain and Shelton 2002). Although loblolly pine produces some seeds every year, bumper seed crops of more than 200,000 seeds/ha (81,000 seeds/acre) generally occur every 3 to 6 years (Baker and Langdon 1990). Effective dispersal distances range from 61 to 91 m (200 to 300 feet) downwind from the source and 23 to 30 m (75 to 100 feet) in other directions

The resistance of hardwoods to topkill from fire also increases with tree size (Waldrop et al. 1987). Larger trees have thicker bark that is less susceptible to cambial damage, and foliage that is higher above the forest floor and less susceptible to crown scorch. Hardwood responses to fire can vary greatly among species. For example, many mature oaks and hickories have relatively thick bark (Harmon 1984). In contrast, species such as red maple, sweetgum, and American beech have thinner bark and are presumably more likely to be girdled by fires. In addition to differences in bark thickness, hardwood species also exhibit differences in the insulating qualities of their bark. In an experiment that controlled for bark thickness, sweetgum, American holly, and black cherry required the least time to achieve lethal cambial temperatures when exposed to flame (Hare 1965). Red maple, water oak, dogwood, tupelo, and birch took longer to reach lethal temperature, and southern magnolia and sweetbay were the most resistant to cambial damage. However, these differences may not translate directly into inter-specific variation in tree mortality under field conditions (Harmon 1984).

Hickories and oaks also tend to invest more energy in root development than species such as red maple and yellow poplar, and are therefore able to resprout repeatedly after being topkilled. In some cases, vigorous resprouting from rootstocks can actually increase the density of hardwood stems following a burn (BROKEN-LINK Brose and Van Lear 1998). If fire does not occur for several years, well-development root systems will send up vigorous sprouts that rapidly reach a height and bark thickness where they can survive most low-intensity surface fires (Van Lear 1991). However, the spouting ability of most hardwoods declines with tree size, so that larger trees may not resprout if they are killed by a high-intensity fire.

See also: Fire Autoecology of Plants.

Autogenic Succession

In the absence of fire, loblolly pine forests exhibit predictable successional trajectories following land clearing, timber harvesting, or other stand-replacing disturbances. Loblolly and shortleaf pines are typically the first trees species to colonize abandoned agricultural lands in the South. The association between loblolly pine and old-field vegetation is so strong that it has been nicknamed ?old-field? pine (Baker and Langdon 1990). Loblolly and shortleaf pines are effective at colonizing these open sites because of their prolific seed production, long-distance dispersal, and high drought tolerance once seedlings are established (Bormann 1953). If abandoned fields are very large, however, pine establishment will be dispersal limited and colonization will proceed much more slowly (Golley et al. 1994, Pinder et al. 1995). The rapid growth of loblolly pine in full sunlight allows it to quickly dominate abandoned fields once it is established (Baker and Langdon 1990). With an adequate seed source nearby, an even-aged cohort of loblolly pine is usually established within 3 to 10 years. (McQuilkin 1940, Oosting 1942).

Pine recruitment typically ceases after approximately 25 years and an understory of hardwoods begins to establish (Oosting 1942, Monette and Ware 1983). Establishment of hardwoods is facilitated by the gradual opening of the pine canopy as self-thinning occurs, and by the accumulation of pine litter that increase soil moisture retention and protects hardwood seeds from desiccation. As overstory pines die as a result of lightning strikes, insect attacks, disease, and senescence, they are gradually replaced by understory hardwoods. Species richness of trees, shrubs, and other understory plants all increase over the first 70 years following field abandonment (Nicholson and Monk 1974). In the absence of major disturbances, shade-tolerant hardwoods will begin to supplant the pines and form mixed pine-hardwood stands within 50-100 years (Monette and Ware 1983, Christensen and Peet 1984). Although hardwoods account for the majority of stems as succession proceeds, the basal area of stands 100-150 years old can still be dominated by a few large, old loblolly pines (Pederson et al. 1997, Abrams and Black 2000). In the absence of major disturbances, the forest will eventually succeed into an oak-hickory dominated climax forest over most of the loblolly range (Quarterman and Keever 1962, Jones 1988, White and Lloyd 1998), or a beech-magnolia climax forest in some portions of the Gulf Coastal Plain (Delcourt and Delcourt 1974, 1977, Glitzenstein et al. 1986).

Forest succession following clear-cutting can differ in several ways from old-field succession. Old-field succession usually results in an initial cohort of pure pine that can persist for several decades before hardwoods establish. Although some mixed pine-hardwood stands in the Southeast represent this middle stage of old-field succession, many others are the result of clear-cutting or selective logging of pine (Ware et al. 1993). After timber harvesting, the forest floor remains largely intact and many tree species can rapidly reestablish from rootstocks or buried seed. Therefore, oaks and other hardwood species typically establish along with pines in the initial post-disturbance cohort and are present throughout succession (Abrams and Black 2000, Harcombe et al. 2002). Nonmerchantable species, such as blackgum, were often left on cutover lands in the early 20^th century (Abrams and Black 2000). In other cases, partial cuts left a mixture of smaller pines and hardwoods (Glitzenstein et al. 1986). These remnant trees can influence post-cutting succession by providing a local seed source, and may still remain a century of more after cutting. In addition, native understory flora can establish relatively rapidly after clear-cutting, instead of requiring decades to reinvade abandoned fields (Hedman et al. 2000).

Fire Effects on Vegetation

The effects of individual fires can be highly idiosyncratic, and are sensitive to weather and fuel conditions at the time of the burn. Both mortality of overstory pines and recruitment of oaks and hickories increased after a surface fire in a 35-year old stand of old-field pine (Oosting 1944, Oosting and Livingston 1964). Thus, a single low-severity fire can increase the rate of succession from pine to hardwood dominance. In contrast, crown fire in another portion of the same stand killed most overstory trees, leading to the regeneration and rapid growth of a new pine cohort. In this case, fire acted to retard succession and maintain a pine-dominated forest. The application of two prescribed burns in a hurricane-impacted stand in east Texas similarly resulted in a shift toward a pine-dominated savannah vegetation type (Liu et al. 1997). However, in this case, the amount of compositional change was slight because the prescribed fires were low-intensity and patchy. Results from another study in East Texas also indicate that the impacts of a single fire on understory vegetation may be minimal if high fuel moisture, low wind speeds, and cool temperatures result in a patchy, low-intensity burn (Rideout and Oswald 2002)

When loblolly pine forests are subjected to repeated fires, the cumulative effects of these fires depend on frequency of burning. For example, uneven-aged forests of loblolly and shortleaf pine in southeastern Arkansas were subjected to winter burning at three, six, and nine-year return intervals (Cain et al. 1998). Areas burned at three-year intervals had lower cover of understory woody plants than unburned controls and areas burned at six- or nine-year intervals. Only the areas burned at three-year intervals exhibited reduced importance of small hardwood stems and a compositional shift toward more fire-tolerant species relative to the unburned areas. All of the burning treatments resulted in higher cover of graminoids and composites than in the unburned controls. Understory species composition of loblolly pine forests in the coastal plain of South Carolina varied similarly along a fire frequency gradient (White et al. 1990). Only the annually burned plots supported high abundances of early-successional grasses, composites, and legumes. Periodically burned plots contained many of these species as well, although some of the poorer competitors were not present. Unburned controls completely lacked this suite of opportunistic ?fire followers?, but contained other shade-tolerant, fire-sensitive species that were absent in the burned plots.

The season of burning also influences the cumulative effects of multiple fires. In general, summer burns topkill more woody stems and affect larger-size stems than winter burns (Brender and Copper 1968). In the Upper Coastal Plain of Alabama, 20-30 year old loblolly and shortleaf pine forests were subjected to both winter and summer burns at a three-year interval (Hodgkins 1958). Plots burned during the winter had lower canopy cover than control plots, and plots burned during the summer had lower canopy cover than those burned during the winter. These differences in cover mainly resulted from different densities of sapling-size trees. Burning during both seasons also resulted in higher shrub and vine cover than in the control plots, but shrub and vine cover was higher in plots burned during the winter than in those burned during the summer.

Experimental plots in the Santee Experimental Forest, located in the coastal plain of South Carolina, were burned at different frequencies (annual, biennial, and periodic) in two different seasons (winter versus summer) from 1946 through 1989 (Waldrop et al. 1992). Periodic burning in both seasons and annual winter burning increased the density of small < 2.5 cm (1 inch) diameter hardwood stems, decreased the density of 2.5 to 12.5 cm (1 to 5 inches) diameter hardwood stems, and had little effect on larger hardwood stems. Densities of small stems were higher than 40,000 stems/ha (16,200 stems/acre) under annual winter burning, compared with less than 20,000 stems/ha (8,100 stems/acre) under period burning, mainly because of increased sprouting of sweetgum (Waldrop et al. 1987). In contrast, annual summer burning greatly reduced hardwood stem densities for all sizes less than 12.5 cm (5 inches). Only the repeated summer fires were able to deplete the carbohydrate reserves enough to kill some of the hardwood rootstocks. Density of shrub stems was lower under annual burning than under periodic burning, and lower under annual summer burning than under annual winter burning. Understory cover was dominated by woody plants under periodic burns. Cover of grasses and forbs was higher under annual winter burns, and comprised the majority of understory cover under annual summer burns.

Although summer burns generally have higher intensities and cause higher mortality than winter burns, this generalization may not hold in some vegetation types. In a shortleaf pine dominated forest in west-central Arkansas, winter burns actually had higher intensities and consumed more fuel than summer burns, even though live and dead fuel moistures were both higher in the winter (Sparks et al. 2002). This difference was attributed to a change in fuel quality between seasons. In the summer, fuel loads were lower and were dominated by live herbaceous fuels. In the winter, fuels were dominated by litter from hardwood leaf fall and dormant herbaceous plants.

In most cases, few data are available to assess the relationship between fire and insect outbreaks in loblolly pine forests. However, there is some evidence to suggest that low-severity fires may increase resistance to some insects. The southern pine beetle (Dendroctonus frontalis) is a major insect pest of southern pines. The oleoresin-producing systems of loblolly and other pine species are the major line of defense against beetle attacks. The formation of radial resin ducts in loblolly pines is positively correlated with growth rates (Deangelis et al. 1986). High-density patches of pine are most susceptible to beetle attack, and prescribed fire can be used to eliminate smaller, high risk trees in these areas (McNab 1977). To the extent that thinning improves vigor of the remaining trees, it will likely increase the resistance to beetle attack. However, fire may increase susceptibility to pine beetles if it reduces the vigor of surviving trees through crown scorch or root damage (Conner et al. 1991). Beetle outbreaks can also influence the intensity of subsequent fires by producing heavy fuel loads (White et al. 1998). Pales weevils and pitch-eating weevils consume the cambium of young loblolly pines, and are mostly a problem in plantations. Burning clear-cut areas eliminates the residual slash in which weevils breed, and may reduce weevil buildup (Fox and Hill 1973).

Fire also influences the susceptibility of loblolly pine to some fungal pathogens. For example, Annosum root rot is a major fungal disease of southern pines. Fire may reduce susceptibility to this disease by removing the litter layer, which harbors most of the Annosum spores (Gooding et al. 1966, Froelich et al. 1978). However, burning has been shown to be less effective than other control and prevention methods, including the application of granular borax over fresh stumps and thinning during the summer month when few spores are released. Also, slow-moving backfires may actually increase susceptibility to root pathogens if they consume most of the duff layer and damage tree roots (Sullivan et al. 2003).

The layer of organic matter on the forest floor is an important component of the surface fuelbed. Thus, the depth and structure the soil O horizon influences fire behavior, and fire in turn inhibits the buildup of organic materials on the forest floor. Loblolly pine forests typically have “mor” type structures with a clear separation between organic material in the O horizon and mineral soil in the A horizon (Fisher and Binkley 2000). The O horizon can be further grouped into three states of decay from non-decomposed material (Oe), to still recognizable but partly decomposed (Oi), to unrecognizable humus (Oa).  Low-intensity prescribed fires often will consume the Oe and Oi layers but leave the more humid Oa layer intact (Brender and Copper 1968, Waldrop et al. 1987). Thus, older, well-developed O horizons are well suited to carry fire but retain a protective organic layer on the soil surface. In fact, such fires are often beneficial in releasing nutrients retained in the O horizon and accelerating the process of recycling nutrients back to the mineral soil.

Higher intensity fires that consume the entire O horizon will have greater impacts on the mineral soil below. If organic material in the mineral soil is also consumed, it can affect soil structure by increasing bulk density, reducing porosity, and reducing infiltration. However, these impacts are atypical of most prescribed fires. Instead, repeated low-intensity burning typically increases organic matter concentrations in the upper layers of mineral soil (McKee 1982). Regular burning also raises soil pH, leading to increases in base saturation and cation exchange capacity. These effects can result in higher availability of phosphorus (P), Calcium (Ca) and magnesium (Mg) in the surface soil layer. Nitrogen (N) availability may also increase with burning. However, volatilization and loss of N in gaseous form typically lead to a reduction in total soil N (Schoch and Binkley 1986, Bell and Binkley 1989). Following a fire, increases in N resulting from N fixation by understory herbs (Hendricks and Boring 1999) and decomposition of the forest floor (Schoch and Binkley 1986) can compensate for these losses. In situations where soil fertility is inherently low, or where high-intensity fires are combined with short-rotation timber harvesting over multiple rotations, frequent burning may ultimately lead to a loss in site productivity (Carter and Foster 2004).

As with any disturbance, fire has the potential to increase erosion. Removal of the O horizon exposes mineral soil to the direct impact of rain, potentially accelerating erosion on steeper slopes. Mortality of trees and other vegetation reduces the stabilizing effects of their root systems. These effects appear to be relatively minor, however, for low-intensity understory fires in Loblolly pine forests. In ephemeral Piedmont streams, watersheds subjected to low-intensity prescribed fire produced the same amount of sediment as undisturbed pine watersheds (Van Lear et al. 1985). Sites treated with a series of low intensity prescribed fires, rather than mechanical thinning, yielded lower levels of sediment load over the long term (Wade et al. 2000). Nutrient losses that occur during burning, other than as N gases, may impact nearby streams. However, leaching losses of nutrients to stream waters after low-intensity surface fires are generally small.  In the case of more intense fires that accelerate erosion, losses of nutrients bound to sediments may increase.

See also: Fire Effects on Soil and Fire Effects on Water.

Fuel/Fire Hazard Reduction

Fuel loading in loblolly pine forests increases with time since burning, reflecting litter accumulation and growth of understory vegetation following a fire (Wade et al. 2000). Prescribed fire is widely used as a fuel reduction treatment throughout the loblolly pine region, mainly because of its relatively low cost and effectiveness at reducing fine fuel accumulations. Winter burns in the upper Coastal Plain of South Carolina resulted in a mean 52% reduction of litter depth, along with a 28% reduction in 1-hour fuel loading, a 15% decrease in 100-hour fuel loading, and a 3% decrease in 1000-hour fuel loading (Scholl and Waldrop 1999). The mean loading of 10-hour fuels actually increased by 22%, probably as a result of canopy scorch and pruning of lower branches in the forest canopy. The treatments also caused a mean 43% reduction in total live fuel loading, and a 61% reduction in live understory shrub fuels.

In an experimental study of alternate fuel treatments in the Piedmont of South Carolina, prescribed burning alone resulted in greater fuel reductions than either thinning alone or thinning followed by burning (Waldrop et al. 2004). Treatments that included fire were particularly effective at reducing the loading of litter fuels. In contrast, treatments that included thinning increased the loading of fine woody fuels in the first post-treatment year. When the first year post-treatment fuel loadings were used as inputs, the prescribed burning treatment produced the lowest flame height and spread rate, whereas the thinning treatments produced higher fire intensities (Mohr et al. 2004).

The effectiveness of prescribed fire at reducing fuels will depend on the weather conditions preceding and during the fire; the amount, types, and spatial distribution of fuels; and the methods used for burning. When prescribed fires are implemented at too low of an intensity, their impact on fuels loadings may be negligible (Rideout and Oswald 2002). The effects of prescribed burning may also be sensitive to other vegetation management activities. Fuel consumption was found to be greater in slash that had been felled in the spring, versus the winter, because continuing transpiration of cut vegetation in the spring resulted in lower fuel moisture and greater flammability (Waldrop 1997).

See also: Using Prescribed Fire for Hazardous Fuel Reduction.

Timber Management

Prescribed fire is frequently used in southern pine management for site preparation prior to seeding or planting (Schultz 1997). Burning is effective both at reducing the vigor of competing hardwoods, and is favored because of its low cost. However, burning alone is rarely sufficient to eliminate hardwood competition or to meet other management objectives, and is therefore usually combined with other mechanical or chemical treatments. Burning immediately before harvesting is often the most effective method of hardwood control, because shaded understory hardwoods have lower vigor than those growing in the sunlight of recent clear-cuts. Alternately, burning late in the growing season and planting or seeding immediately thereafter provides pine seedlings with the greatest competitive advantage over hardwoods. Low-severity winter burning may actually stimulate the sprouting of hardwoods in the following growing season. In addition to suppressing hardwood competition, prescribed burning also reduces the litter layer and creates suitable conditions for natural regeneration (Cain and Shelton 2002).

Once a cohort of loblolly pines is established, fire can be applied as a tool for pre-commercial thinning. Prescribed burning was used to reduce the density of a young loblolly pine stand in the lower Piedmont of Georgia from more than 24,700 trees/ha (10,000 trees/acre) to 8,600 trees/ha (3,500 trees/acre) (McNab 1977). Tree diameters in the pre-fire stand ranged from 1.3 cm (0.5 inches) to 15.2 cm (6 inches), and no trees greater than 10.1 cm (4 inches) in diameter were killed by the fire. This method is only recommended in situations where trees sizes span a relatively wide range of diameters.

Prescribed fire can also be applied during the rotation to reduce competition from woody vegetation. Numerous studies have demonstrated that fire can reduce the dominance of understory trees and shrubs. The effects of fire are usually greater under more frequent burning regimes, particularly when annual growing season burns are applied (White et al. 1990). However, these reductions in understory vegetation do not always translate into more rapid growth of crop trees. Under controlled conditions, growth of loblolly pine seedlings was enhanced by long term, annual winter burning (McKevlin and McKee 1986). In contrast a comparison of growth rates of overstory loblolly pines over a 41-year period showed negligible differences in the rate of basal area growth per hectare between an unburned control and plots subjected to different seasons and frequencies of fire (Waldrop et al. 1987). This lack of response was attributed to the fact that the stands were already 40 years old at the onset of the experiment.

Several other factors may also limit the potential for increased tree growth in response to understory vegetation control with prescribed fire. Although mature trees are seldom killed by the crown scorch from controlled surface fires, severe crown scorch may result in a temporary decrease in growth. Following a single prescribed burn in a 17-year old loblolly pine plantation in South Carolina, height growth of crop trees was reduced compared to an unburned control and diameter growth was unaffected (Waldrop and Van Lear 1984). Diameter growth in a 19-year old naturally regenerated loblolly pine stand in southeastern Louisiana decreased following a prescribed fire (Lilieholm and Hu 1987). Smaller trees and trees with more crown scorch had the largest growth reductions, and the growth of most trees recovered within three years after the fire. Burning also releases N and other essential nutrients to the atmosphere as gasses and particulates (Carter and Foster 2004). When frequent prescribed burning is combined with short-rotation timber harvesting and broadcast burning for site preparation, nutrient losses may translate into reduced site productivity and lower timber yields.

See also:  Using Prescribed Fire in the Silviculture of Loblolly Pine.

Wildlife Management

Upland game species such as cottontail rabbit (Sylvilagus floridanus), fox squirrel (Sciurus niger), gray squirrel (Sciurus carolinensis), white-tailed deer (Odocoileus virginianus), bobwhite quail (Colinus virginianus), mourning dove (Zenaida macroura) and wild turkey (Meleagris gallopavo)are all found in loblolly pine or loblolly-hardwood stands (Mobley and Balmer 1981). Many non-game species and some threatened and endangered species also utilize these forest habitats. Most species native to the region evolved in the diverse habitats of former pre-settlement forests and are not adapted to conditions in pure pine forests. For example, white-tailed deer prefer different habitats and food sources at different points in their life cycle. Species such as the red-cockaded woodpecker (Picoides borealis), gopher tortoise (Gopherus polyphemus), and indigo snake (Drymarchon corais) require open savannah habitats that are not replicated in most closed-canopy pine forests. However, by maintaining diversity in stand structure, age and timber types, with some mast-producing hardwoods where feasible, habitat for many can be provided with little economic impact on timber production (Johnson 1987). Prescribed fire can be used to alter both the structure of forest stands and the plant species available for wildlife nutrition, and is thus an important tool for managing wildlife habitat in loblolly pine forests.

Regenerating pine stands often provide a large quantity of woody vegetation, herbaceous plants, and fruits beneficial to some mammals and birds (Dickson and Huntley 1987). This early-successional habitat generally deteriorates within 7–10 years as canopy closure shades out non-pine vegetation. A few species such as the brown-headed nuthatch (Sitta pusilla) are strongly associated with pure pine stands. However, the species richness and abundance of bird communities generally increases over the course of forest succession as young pine stands mature and develop a hardwood component (Meyers and Johnson 1978).

Most bird species in southern pine forests are more sensitive to understory vegetation than to overstory structure (Johnston and Odum 1956). Grassy understories favor species such as bobwhite quail and Bachman’s Sparrow (Aimophila aestivalis). Shrub dominated understories favor other species such as the Carolina Wren (Thryothorus ludovicianus), the great crested flycatcher (Myiarchus crinitus) and the Summer Tanager (Piranga rubra), the Yellow-throated Vireo (Vireo flavifrons), the Eastern Wood Peewee (Contopus virens), and the Hooded Warbler (Wilsonia citrine) (Meyers and Johnson 1978). Thus, to the extent that prescribed fire influences the composition and structure of understory vegetation (Waldrop et al. 1987, Waldrop et al. 1992, Cain et al. 1998), it will also affect bird habitat.

Winter burns are often more effective than summer burns at promoting the development of wildlife foods, because summer fires may temporarily eliminate critical browse plants needed in the fall and early winter. Loblolly pine stands in South Carolina burned every winter for 20 years showed an increase in food plants valued by wild turkey, such as winged sumac (Rhus copallina), beggartick (Bidens spp.) and partridge pea (Cassia spp.), whereas adjacent plots burned annually in the summer had lower levels of these species (Degraff et al. 1991). On the Coastal Plain of South Carolina annual winter burns produced high quantities of forbs producing superior habitat for quail (Lewis and Harshbarger 1976).

However, not all species are best served by annual winter burning. Frequent fires can weaken browse plants to the point where they seldom produce much foliage and fruit, limiting their habitat value. In pine-hardwood forests, understory burning is recommended at 5-10 year intervals to provide ample berries and mast for black bears (Hamilton 1981). White-tailed deer benefit from a more frequent regime of spring burns (Halls 1978). A 3 to 5 year burn regime keeps browse within reach without having the detrimental effect on fruit and mast production and spring burning promotes resprouting of vegetation. For southeastern forests in general, prescribed winter burning over a 3 to 6 year interval is recommended to increases the quality, quantity, palatability and accessibility of a variety of grasses, forbs and shrubs that provide food for many game and non-game species (Schultz 1997).

Habitat for several threatened and endangered species such as the Gopher tortoise, indigo snake and red-cockaded woodpecker are improved by burning (Wade and Lunsford 1988). Red-cockaded woodpeckers (RCW) prefer old growth, open, pine dominated stands for nesting and foraging. RCWs form nesting and roosting cavities by excavating holes infected with the red heart fungi (Phellinus pini) in large pines. These fungi decay the heartwood of the tree while leaving the exteriors intact (Conner and Locke 1979) and mature trees are more likely to be affected. The average loblolly pine cavity tree is more than 75 years old and greater than 23 cm (9 inches) dbh (Schultz 1997). A single family may require more than 50 ha but may thrive in as little as 28 ha in high quality habitat (Conner et al. 2001). Stands adequate for RCW contain at least 1.7 m²/ha (7.4 ft²/acre) of pine basal area/ha. The presence of hardwoods may reduce the quality of RCW habitat by attracting other woodpecker species and increasing competition for pine resources. Prescribed fire is useful for reducing hardwood component but old cavity trees may be very susceptible to intense understory fires. For this reason colony sites should be protected by raking fuel at least 3 m (10 feet) away from cavity trees and burning the areas separately with cool backfires (Conner and Locke 1979).

Other species of birds, such as Bachman’s sparrow, brown-headed nuthatch and pine warbler do well on pine stands managed for RCW’s (Schultz 1997). Other birds associated with early successional pine stands, such as common yellowthroat (Geothlypis trichas), yellow-breasted chat, field sparrow (Icteria virens), grasshopper sparrow (Ammodramus savannarum) and indigo bunting (Passerina cyanea) often benefit from prescribed burns (Dickson 1981). Zebahazy et al. (2004) reported that bird abundance did not change because of fuel reduction treatments, including both thinning and burning, but species richness increased. Foliage-gleaning and canopy nesting species were more common in thinned sites than in burned. A drawback is that these treatments may increase risk of predation on birds.

Most lightning-caused fires occur in the summer when conditions are driest and most amphibian species are underground or close to water. Prescription burning often occurs in the spring and some amphibians may be migrating to water for reproduction or dispersing to breeding sites and may be more vulnerable to fire (Pilliod et al. 2003). However, Schurbon and Fauth (2003) suggest that a burn interval of approximately 5 years applied during the growing season is better for amphibian diversity in longleaf pine stands. Russell et al. (1999) suggests that returning prescribed fire to the southeastern coastal plain would likely benefit herpetofauna by restoring historical mosaics of successional stages, habitat structures and vegetative species composition. In the southeast firebreaks created around isolated wetlands may be harmful to species that do poorly in ponds where hardwood succession and canopy closure has resulted from years of fire suppression.

See also: Using Prescribed Fire to Improve Wildlife Habitat and Fire Effects on Fauna