1Up Info - A Portal with a Difference

1Up Travel - A Travel Portal with a Difference.    
1Up Info

Earth & Environment History Literature & Arts Health & Medicine People Places Plants & Animals  Philosophy & Religion   Science & Technology Social Science & Law Sports & Everyday Life Wildlife, Animals, & Plants Country Study Encyclopedia A -Z
North America Gazetteer

You are here >1Up Info > Wildlife, Animals, and Plants > Kuchler Potential Natural Vegetation Type > Oak-Hickory Forest

Wildlife, Animals, and Plants


Wildlife, Animals, and Plants


Wildlife Species











  Fern or Fern Ally








KUCHLER TYPE: Oak-hickory forest
FUELS, FLAMMABILITY, AND FIRE OCCURRENCE : Fuels and Flammability: In the Sand Prairie Scrub Oak Nature Preserve, Illinois, estimated fuel loads were highest in closed forest, moderate in savanna, and lowest in prairie. When blackjack oaks in savanna reach sufficient size, grass growth under their crowns is reduced and wind action sweeps away litter; this reduces the amount of fuel near the tree trunk and prevents fire from reaching the tree base. Following a spring prescribed fire, a study of patterns of fuel consumption around isolated blackjack oak savanna trees showed that fire never reached their bases. In closed forest, tree mortality was high, and trees experienced more scorch at stem bases than trees on the forest-prairie edge [5]. In hardwood stands in the north-central states, fire danger is high in both the spring and fall and low in the summer months when the vegetation is green [64]. At Indian Creek Nature Center, Iowa, prescribed fires were conducted in spring under moist conditions in grassland and adjacent oak-hickory woodlots. In the woods, fires were generally patchy and left large areas unburned [73]. Oak leaf litter affects the likelihood of fire and increase fire intensity [54]. Oak leaves crinkle up when they dry and are therefore held above the ground surface creating a loose, porous fuel bed that carries fire easily [54,73]. In contrast, leaves of locust (Robinia spp.), maple, and elm lie flat, stay damp, and do not burn well [73]. Oak leaf litter is easily carried by wind; burning leaves can ignite spot fires and increase fire spread. Dead leaves of black oak often remain on the tree, creating deep layers of dry fuels in young stands [54]. Wildfire hazard has increased due to fuels buildup and fire exclusion on the Hercules Glades Wilderness Area in southwestern Missouri since its designation as wilderness. Management-ignited fire and prescribed natural fire have been recommended [56]. Fire Occurrence: It is widely accepted that along the western boundary of the deciduous forest Native Americans set many fires that kept oak-hickory forests open, helped determine the grassland-forest boundary, and limited the range of maple-basswood forests [73,97]. Nearly every acre in the Midwest probably experienced at least occasional fire [73]. There are numerous reports of Native Americans burning Missouri savannas and grasslands on an annual basis, usually in the autumn after leaf-fall [22,56]. Northern Missouri was virtually fire-free soon after settlement; southern Missouri continued to be burned by early settlers, but fires were of lower severity than presettlement, aborigine-set fires. In 1936, the state Conservation Commission began a concerted effort to suppress fire throughout the state [22]. In the Missouri Ozarks, fire history of a post oak savanna growing on a ridge was reconstructed for 1734 to 1991 using tree ring analysis. The mean fire return interval from 1740 to 1850, the period of greatest fire frequency, was 2.8 years. After 1850, the fire return interval increased to 24 years [26]. In southern Wisconsin (the area mapped by Kuchler as oak savanna [K081] but containing virtually the same species as oak-hickory forests and bluestem prairie-oak-hickory mosaic), oak savannas were widespread and common in presettlement times and disappeared rapidly as soon as fires ceased. It was therefore estimated that presettlement fire frequency was very high and in some areas fire occurred annually [54]. In the north-central states, there were more than 11,000 fires reported between 1970 and 1972. Many fires were caused by debris burning (approximately 33%), many were incendiary (20%), and only a very few (1%) were started by lightning. More than 50 percent of the fires burned in hardwood stands [64]. Boerner and Cho [10] estimated fire return intervals for heavily forested sites in southeastern Ohio from 1923 to 1978. They calculated an average fire return interval of 643 years given current conditions. Average fire intervals of 900 years were estimated for the Shawnee National Forest, Illinois [54]. FIRE EFFECTS ON SITE : In Missouri seasonal rates of nonsymbiotic nitrogen fixation in surface soils of oak-hickory forests were measured on plots exposed to 30 years of annual or periodic prescribed fire. Fire treatments had no influence on fixation rates, which averaged 0.1 kg/ha/year, or on the proportion of samples showing nitrogen fixing activity [93]. In Missouri annual fire in oak-hickory forests may reduce nutrient availability and water infiltration. Burning significantly reduced quantities of extractable ammonium in the soil; annual burning resulting in lower amounts than burning every 4 years [92]. In Missouri, oak forests were prescribed burned annually or periodically (every 5th year) in spring. Annual fires were patchy and of low severity due to lack of surface fuels. Soils of annually burned plots became increasing compacted and had little or no earthworm and insect activity compared to unburned soils and litter. After seven annual fires, water infiltration rates were 4.5 times faster on unburned soils than on burned soils [73]. Arend [111] reported reductions in infiltration rates after prescribed fire for some soils under mixed upland oaks in Missouri. FIRE EFFECTS ON VEGETATION : Fire is an important factor in establishing and maintaining vegetation patterns in the Ozark Mountains [2,74]. The closed-canopy oak-hickory forest that now predominates in the Missouri Ozarks is thought by some authors to be an artifact of fire suppression and other anthropogenic disturbances. People travelling in the area in presettlement times described a wide variety of plant communities ranging from grassland, to oak savannas, to oak-pine forests [26]. Repeated fires create open, parklike stands of oak [90]. Drought is the primary agent controlling the frequency and severity of fire and the impact of fire on trees in oak-hickory forests. Drought contributes to low fuel moistures and therefore high fireline intensity, resulting in more severe fire. Individual trees stressed by drought are more susceptible to pathogens after fire wounding and sprout less vigorously after top-kill. Stands affected by insects or pathogens also have high amounts of fine fuels [17]. Species Responses: Most oaks are resistant to fire to some extent; fire resistance generally increases with stem diameter [54,78]. Most oaks sprout from dormant basal buds after top-kill. Sprouting species are favored over other hardwoods by occasional fires [23]. Boerner and Cho [10] hypothesized that large, emergent oaks in an old-growth forest in southeastern Ohio were established following one or more large-scale disturbances such as fire or windstorm. After oak establishment on good sites, severe fire maintains oak dominance [54]. Rouse [78] listed the following oaks in order of decreasing bark thickness: chestnut oak, black oak, northern red oak, and white oak. Lorimer [53] rated upland oaks slightly differently in order of decreasing bark thickness: bur oak, black oak, white oak, and northern red oak. The thinner bark of northern red oak may acount for its susceptibility to top-kill by fire. Bur oak and white oak are often maintained in oak savannas, whereas frequent fire reduces northern red oak to shrubby clumps of sprout origin. Black oak is a short-lived (less than 150 years) tree, intermediate in shade tolerance. It sprouts after injury or top-kill. Susceptibility to fire is intermediate in larger individuals and high in young seedlings and sprouts [42]. Both mature [110] and young black oak seedlings sprout [54]. Fire-caused basal wounding provides entry for wood-rotting fungi and insects [74]. Loomis [52] published a method for predicting tree mortality and estimating basal wound size for surviving trees. Mortality equations were derived for black oak, white oak, post oak, and scarlet oak. The black oak formula also applies to hickories and to northern red oak. Mortality depends on tree species, diameter at breast height, height of bark blackening, and the width of bark blackening at 1 foot above the ground [52]. Prescribed spring fire in grasslands and adjacent woods in Iowa resulted in a great increase in flowering of forbs, and reduced woody species such as common prickly-ash (Zanthoxylum americanum), black locust, barberry, buckthorns, and maples [73]. Survival of lichens after fire in a Michigan oak savanna was summarized by Wetmore [105]. Many species showed lower cover after fire on the part of tree trunks closest to the soil; cover reduction was less pronounced high on the tree trunks, even at high fire frequencies [105]. Effects of Fire on Species Composition: Fire influences species composition towards oak-hickory and away from maple-beech dominated forest [15]. After a severe wildfire in West Virginia, oaks increased from 9.3 percent of the dominant trees to almost 30 percent of the total, mostly due to top-kill of mesic hardwoods [54]. Frequent fire reduces tree and shrub cover in favor of prairie species. In the Driftless Area (Wisconsin and Minnesota), almost pure stands of northern red oak occur on moist sites that would be suitable for sugar maple. These are even-aged stands that probably established after severe fires [23]. In many oak-hickory forests, sugar maple and other shade-tolerant and fire susceptible species are increasing in number and cover. Evidence that this is a result of fire exclusion includes the tendency of sugar maple and other fire-susceptible species to co-occur on protected sites that show no evidence of past fire [67]. In southern Wisconsin oak forests (which experienced fire in presettlement times but have not burned recently), oak regeneration is scarce. McCune and Cottam [59] suggested that since none of the understory species in southern Wisconsin (hackberry, boxelder, American elm, butternut, black cherry, and red maple) are true climax species, the absence of disturbance is an historic anomaly and the future composition of these forests is unclear. Henderson [42] compared two black oak stands in Indiana with differing fire histories. The stand which had experienced frequent, low-severity surface fires was dominated by black oak and a few northern red oak, and there were few other woody species. The stand that had experienced more severe fire less frequently was also dominated by black oak, but had less fire-tolerant species present as well: red maple (Acer rubrum), sassafras (Sassafras albidum), and black tupelo (Nyssa sylvatica) [42]. In Illinois grassy openings with few trees were burned annually with prescribed fire from 1969 to 1973. They were not burned again until 1990, 1991, and 1992. With annual fire, prairie forbs increased and woody species declined. In the 15-year fire-free interval, the number of shrub species increased. When prescribed fire was resumed, prairie willow (Salix humulis) and silky dogwood (Cornus amomum) sprouted vigorously after fire; prairie forbs also increased [3]. Effects of Fire on Stand Structure: Fire was important in maintaining oak savannas at the forest-prairie ecotone. There are numerous historical references to the rapid conversion of savanna to oak forest following European settlement and cessation of fire [23]. Anderson and Brown [5] proposed that the mosaic of presettlement vegetation types was strongly influenced by fire patterns that tended to limit closed forests to areas protected from most fires. In Tennessee annual and periodic prescribed surface fires were conducted in upland oak-dominated vegetation. Upland stands were mostly post oak-blackjack oak, southern red oak-scarlet oak, or white oak [30]. After 25 years, understory cover of woody plants was irregular but more or less constant in annually burned plots. Overstory cover was open, with few trees per acre. In periodically burned plots, woody understory cover increased irregularly. In unburned control plots, woody understory plant cover first decreased but then increased over the 25-year period [29]. In presettlement Indiana grass-dominated openings were maintained by annual burning after autumn frost. These frequent fires prevented the growth of trees and "permanent vegetation". In less than 50 years without fire, former openings were converted to forest [49]. Repeated fires are thought to be responsible for scrub oak lands (stands of scrubby oaks of sprout origin) in the Midwest [23]. In the Sand Prairie Scrub Oak Nature Preserve, a March 1977 prescribed fire in closed forest consumed 95 to 99 percent of the surface litter in study plots. Numerous trees had fire scars up to 3.3 feet (1 m) above the ground. In the savanna the fire did not reach within 1 foot (30 cm) of the base of any of the 14 trees. Surface area burned ranged from 7.1 percent to 52.4 percent in different plots. None of the savanna trees showed any deterioration in 3 years after the fire even though some had scorching of the lower branches [4]. Black oak sand savannas at Hoosier Prairie Nature Preserve, Indiana, are maintained by prescribed fire. One area has been burned four times in 8 years, three times in the spring, and once in the fall. The number of woody stems increased after the first fire, but decreased thereafter. Postfire sprouting of smooth sumac occured at the same rate through four fires, but black oak and prairie willow sprouting rates declined. Another area of oak savanna at Hoosier Prairie was burned five times in 8 years. Allowing plots to rest from fire for least 2 years resulted in an increase in the numbers of woody stems, but the number of woody stems decreased after two consecutive fires [7]. FIRE EFFECTS ON RESOURCE MANAGEMENT : Few instances of direct mortality from fire have been recorded for wildlife species in oak-hickory forests. In Oklahoma, Bigham and others [9] observed many dead eastern box turtles immediately after severe fires in post oak-blackjack oak woods and adjacent pasture and range. They also observed living turtles, snakes, northern bobwhites, and a rabbit on the burned area 4 days after the fire [9]. FIRE USE CONSIDERATIONS : Moore [66] published a method for field measurement of fuel moisture to assess burning conditions in oak-hickory forests. FIRE MANAGEMENT CONSIDERATIONS : Fire was once an important factor in the oak-hickory ecosystem and maintained the open character of most stands in the Midwest [15,54]. Many historians and ecologists feel that the midwestern oak-hickory forests evolved with frequent fire and remain fire-dependent [73]. Prescribed fire is useful for maintaining the diversity of oak-hickory forests, and is being used in Indiana, Illinois, Missouri, Wisconsin, and Iowa with good results. Prescribed fire use continues in hardwood and mixed forests as a wildlife management tool [106] and to modify understory composition or size class structure [35,99]. Unfortunately, few short- or long-term ecological studies of fire perturbations have been conducted on oak-hickory forests [15]. Implications for fire in management of currently existing closed-canopy forests are unclear. Regeneration problems associated with these forests are similar to problems occurring in forests farther east. Prescribed fire is being considered as a silvicultural tool in oak forests. It seems likely that several low- to moderate-severity prescribed fires will reduce the number of shade-tolerant competitors, and it is possible that such fires may encourage establishment of oaks. A single fire will have little lasting impact, and in some cases may be detrimental to oak regeneration. Several fires are probably necessary to select against less fire-resistant competitors [54]. Lorimer [54] commented that experiments with medium-severity fire are to be encouraged; low-severity fire may not kill competing species at rates high enough to be beneficial to oak regeneration. In some areas silvicultural approaches may be as least as successful as prescribed burning programs [54] because basal wounding by fire allows entry of fungi and insects and reduces the value of timber trees [74]. In an attempt to improve oak regeneration in an upland hardwood forest in northern Alabama, a prescribed fire was conducted in 4- to 6-year-old oak stands that appeared to be in danger of replacement by other species. One fire in these stands did not substantially alter the trend to replacement of oaks by other species. Stands recovered rapidly from fire; density of browse species and herb cover increased, resulting in improved wildlife habitat [45]. With increasing age of forests, regeneration of oaks after disturbance tends to decrease. Sprouting tends to decrease with age. Established shade-tolerant species in the understory and subcanopy are more competitive than low-vigor oak sprouts [15]. In the Midwest many savanna and grassland areas have been prescribed burned on a regular basis. These fires have been prevented from spreading into adjacent forests, with the result that there are no transitional areas. Under presettlement conditions, grassland fires sometimes spread into adjacent oak-hickory forests, depending on local conditions. These fires maintained savanna and ecotonal communities in irregular mosaics. It has been recommended, therefore, that prescribed fires for grassland maintenance be allowed to burn into adjacent forest and reestablish savanna vegetation and ecotones [73]. In Indiana fire management policies are based on the premise that oak savanna and prairie communities will best be maintained by a fire interval of 2 to 8 years, depending on unit history and specific goals. Annual fires are not recommended for either restoration or maintenance of oak savanna because there is usually not enough fuel to carry fire, and annual fires may damage some herbs. Remnants of oak savanna prairie need to be burned at least every 15 years or they will develop into dense forest. Spring fires are thought to be the most effective [32]. In Indiana black oak sand savannas, maintenance and restoration of vegetational mosaics was initiated with prescribed fire. Plots were burned biennially, three times in the spring and once in the fall, for a total of four times in 8 years [7]. On the Grand Prairie, Illinois, U.S. Forest Service personnel are attempting to restore the transition landscape (as savanna) by allowing firewood removal until approximately 10 trees are left per acre (25 trees/ha); tree removal is followed by annual prescribed fire [58]. There has been some debate over the choice of sites and appropriate methodology for restoration of presettlement vegetation including savannas [60,72]. Mendelson and others [60] contend that savanna vegetation represents an ecotonal and therefore not unique vegetation type and should not be created by artificial means. Packard [72] and his colleagues believe that, since the presettlement vegetation has been grossly disturbed by humans, drastic measures (i.e., prescribed fire and tree thinning) are necessary to restore savanna and other presettlement vegetation types. REHABILITATION OF SITES FOLLOWING WILDFIRE : NO-ENTRY

Related categories for Kuchler Type: Oak-hickory forest

Send this page to a friend
Print this Page

Content on this web site is provided for informational purposes only. We accept no responsibility for any loss, injury or inconvenience sustained by any person resulting from information published on this site. We encourage you to verify any critical information with the relevant authorities.

Information Courtesy: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Fire Effects Information System

About Us | Contact Us | Terms of Use | Privacy | Links Directory
Link to 1Up Info | Add 1Up Info Search to your site

1Up Info All Rights reserved. Site best viewed in 800 x 600 resolution.