The Paleo-Indian occupation of the ANF occurred during the latter stages of the Wisconsin glaciation, probably during the Valders glacial substage, at about 9,000 B.C. The environment of this period reflected the proximity of the retreating ice mass which was located north of the St. Lawrence Valley. Miller (1973) defines this period on the basis of pollen samples from the Allenburg Bog as the rapid advance of the early tundra vegetation was closely followed by an open spruce boreal woodland.

The dispersal of early migrants through this region was dictated to a large extent by the residual effects of glaciers. High water levels in the rivers, fed by glacial runoff and often impounded by end moraines, may have restricted Paleo-Indian movements, although valleys of Brokenstraw Creek, the Allegheny River, and Conewango Creek provided a natural route of transportation that Lantz (1984; 1985) has coined "the Paleo-Indian Corridor."

Small loci of Paleo-Indian occupations exhibiting a relatively limited range of activities dominate the archaeological record. Characteristically, they contain few artifacts which are representative of a limited number of activities (Lantz 1984; 1985).

It has been suggested that the distribution of extractive type sites is based on the patterns of migratory herd animals, caribou in particular, and that seasonal moves, north and south along valley routes in pursuit of these animals, provided Paleo-Indian hunters with the initial familiarity of the region that preceded actual settlement (Ritchie and Funk 1973:6) and that band type territorial units may have been established on the basis of access to migratory corridors. The presence of exotic lithics, even in low frequencies, at a high percentage of these sites indicates at least peripheral contact with other regions (Lantz 1984; 1985).

Due to the general absence of faunal remains, an analysis of the subsistence base is restricted to inferences based on the faunal assemblage present during the late Pleistocene and functional analysis of the recovered artifacts. Although no evidence of plant food preparation has been recovered, the utilization of this consistent resource base has to be considered. There seems to be no reason not to assume that Paleo-Indian hunters utilized not only large migratory herd animals but all available smaller animals and such plant foods as could be foraged (Ritchie and Funk 1973:335; Lantz 1984; 1985).

The Early Archaic represents the initial cultural adaptation to post-Pleistocene environmental conditions. Not much is known about the Early and Middle Archaic Periods in this area. There is little information available on site patterning, associated tool assemblages, and subsistence. The climate during the Middle Archaic Period is thought to have been hotter and drier. The onset of warmer climatic conditions, brought with it a migration of plants and animals associated with essentially modern climate.

The Late Archaic period on the ANF and in northwestern Pennsylvania is associated with the maximum spread of the Oak-Hickory forest association across much of the Unglaciated and Glaciated Allegheny Plateau. Although the Oak-Hickory association never dominated the Unglaciated Plateau on the ANF, it spread extensively up many runs and streams which had previously been dominated by hemlock and beech. The Hemlock-Beech association remained dominant on the slopes and plateaus throughout the rest of prehistory and into early historic times until much of it was logged off in the late nineteenth and early twentieth centuries. Concomitant with the spread of the Oak-Hickory forest association is an increase in the human population density of northwestern Pennsylvania and in the ANF along the Allegheny River and its major tributaries. Extensive groves of harvestable nuts (acorns and hickory nuts) were available for exploitation by both deer and humans, and it is postulated that Late Archaic peoples depended upon deer and nut harvests, although they also utilized a variety of other floral resources in a seasonal cycle of food resource procurement. The appearance of ground stone tools and heavy-duty woodworking tools of the Late Archaic, Transitional and Early Woodland Periods (ca. 4,000 B.C.-A.D. 1), along with the presence of nut hull fragments in archaeological features at base camp sites of these time periods, suggests that prehistoric human manipulation of the forested landscape was a part of settlement-subsistence systems (Munson 1986; DeVivo 1990; Adovasio et. al. 1997; Delcourt and Delcourt 1997; and Ruffner et. al. 1997). Limited forest clearance suggesting relatively serious horticulture could also reflect what some archaeologists (McCoughnnaughy 1997) call "sylviculture" --the intentional removal of under-story and second-growth vegetation to enhance the collection of nuts in a mast forest context. (Adovasio, et. al. 1997).

Cultigens helped reduce the dependence on hunting and gathering and allowed for the development of a more sedentary existence as evidenced by the presence of large village sites (Cowin 1985; Snow 1994; Ruffner et. al. 1997). Most occupation sites are located on river or glacial outwash terraces (Ritchie and Funk 1973; Snow 1994; and Lantz 1982). The availability of arable land was no doubt a major consideration for site location, due to requirements of a horticultural economy (Aldenderfer and Dean 1981). After a decade or so villages would be moved because of depletion of soil and wood (Ritchie and Funk 1973; Sykes 1980; Snow 1994). Late Woodland villages in the area characteristically tend to be protected with a wooden palisade (Ritchie and Funk 1973; Snow 1994; and Lantz 1982). Construction and occupation of village sites would, therefore, have required the inhabitants to use and consume a considerable amount of timber and fuelwood (Ruffner et. al. 1997). Thus, the anthropogenic landscape in the Allegheny River Valley and its major tributaries during the Late Woodland period would have resembled a mosaic pattern of 1) crop lands near palisaded settlements, 2) abandoned clearings with early successional taxa, and 3) open forest stands dominated by fire-adapted species such as oak and hickory (Chapman et. al. Delcourt 1987; Clark and Royall1995; Ruffner et. al. 1997). The Huron, an Iroquoian group to the north in southern Ontario, were known to have their village sites located near old growth white pine stands may be applicable in the Allegheny Valley as well.

Beginning in the Middle Woodland and continuing throughout the Late Woodland period the Oak-Hickory forest along smaller runs and streams on the plateau is gradually replaced by an Oak-Hemlock assemblage which led to a reduction of the deer population in and around the Forest. This, in turn, suggests that the uplands may have been lightly utilized during the Middle Woodland period (Aldenderfer and Dean 1981). However, given the increased population density during the Late Woodland period when larger villages became common and when numerous campsites of the period are scattered throughout the forest, it is likely that much of the Forest was utilized by hunters and collectors who supplemented the maize diet with other resources. With an increased population density, even relatively poor environments, such as the uplands around intermittent streams, would have been exploited for game and other resources (Aldenderfer and Dean 1981).

It was during the Late Woodland period when the Neo-Boreal or Little Ice Age occurred which in the marginal agricultural areas on the ANF where productivity was dependent on latitude and altitude, farmlands were becoming unproductive. Biotic boundaries are not static. When climate changes the boundaries shift, and when boundaries shift, the subsistence base may be affected, especially in certain sensitive areas in high latitudes where conditions for plant growth and horticulture are marginal (Johnson, et. al. 1979).

The Historic sequence in the ANF begins with historical accounts written by European explorers in the area. The first of these is Celeron de Blainville, who traveled down Conewango Creek and the Allegheny River by canoe in 1749 to claim the Ohio Drainage for France. By the time that this area was being explored by Europeans, the indigenous populations of the previous period were replaced (i.e., through displacement and/or assimilation) by Iroquoian groups from New York. Munsee/Delaware groups pressured by Euroamericans in the east also relocated in the area about this time. The Seneca Nation of the Iroquois Confederacy apparently allowed the Delaware to relocate to the Allegheny Valley and exercised control of the refugee Indians. The locations of the Seneca and Delaware/Munsee settlements probably shifted somewhat through time, but lay along the Allegheny River. Among the plants introduced by Iroquoian groups was black walnut (Juglans nigra). Other favorite food nuts of the Iroquois included beech nuts (Faus grandifoliea), butternuts (J. cinerea), chestnuts (Castanea denta), hickory (Carya cordiformis and Carya ovata), and hazel (Corylus americana). Nuts were an important part of Iroquoian diet. In nearby New York State Father Fremin, among the Seneca in 1669 complains that it was not easy to save souls because people were so overjoyed by the unusually abundant harvest of nuts that "one sees everywhere only games, dances, and feasts which often reach the point of debauchery (Wykoff 1991).

This first extensive exploitation of forest resources in the ANF occurred soon after the American Revolution when Indian claims became resolved. The original forest cover reportedly was hemlock/beech/maple. Early settlers focused on harvesting white pine, which occurred in pockets, perhaps the sites of abandoned Indian villages or where fires or windstorms had created openings. The white pine resources were exhausted as the Industrial Revolution accelerated, and hemlock became the focus of forest exploitation (Marquis 1974; 1994).

The early exploitative logging in the hemlock/beech/maple types in the area, however, did not result in extensive clear-cutting. Trees of the desired quality were scattered, and the technology required to move large volumes of logs was not well enough advanced to permit clear-cutting of major portions of the virgin forest. Most of the clear-cutting was still confined to areas where streams could be used to transport logs to the mill. The result was that early cuttings tended to be scattered and patchy, partial cuts that left considerable amounts of over-story trees in most places. Sunlight levels on the forest floor increased, but conditions still favored seedlings that had a high tolerance for shade. Sugar maple and beech prospered in these conditions; forest under-stories were dense with seedlings and saplings of these species, making these areas ideal sources for the chemical wood factories that came later (Marquis 1974; 1994).

The Industrial Revolution simultaneously created high demand for the products of forest exploitation and the technology to increase the efficiency of the exploitation. Three industries dependent upon forest products were critically important at about the turn of the century: the wood products industry, the tanning industry, and the chemical wood industry. At about the same time, railroad technology designed especially for logging was developed. Railroads could reach almost everywhere for logs, and they did (Marquis 1974).

The result was that between 1890 and 1920, the forests in the region were almost completely clear-cut in "what must have been the highest degree of forest utilization that the world has ever seen in any commercial lumbering area" (Marquis 1974:11).

But economics and the patterns of industrial development may have had differential effects on the forest. A gross generalization of the effect of the Railroad Logging Era is that close to the railroads associated with chemical wood factories, where haul distances were short, trees of all sizes were cut, resulting in clear-cuts as complete as modern commercial clear-cuts can be. In these conditions, sun-loving species, especially black cherry, a minor component of the original forest, thrived. Stands that were not close to chemical wood company railroads had a different fate. Here, only the larger, more valuable trees were removed, and the saplings of beech and sugar maple that had started after 19th century removals of hemlock and white pine survived and prospered. Throughout the ANF, this pattern was repeated. Where railroads serving chemical wood companies reached into the forest, the dominance of sun-loving black cherry may be a reflection of the railroad logging pattern. On the other hand, where today's forest canopy is composed of a mixture of species, this may reflect where the less complete cuts for sawtimber products only had occurred.

The present forest cover now hides the numerous archaeological remains of logging railroads, chemical wood factories, huge band sawmills, lumber camps, and old town sites.

In the early part of this period, the Great Depression occurred. Such an event might very well have accelerated the exploitation of the remaining natural resources; however, direction that the Roosevelt Administration took was to put millions of unemployed workers to work on conservation projects not only on the ANF, but in the region and throughout the country. The New Deal programs of the 1930's, especially the Works Progress Administration (WPA), brought new jobs into the region and were the driving force behind the construction of new roads, bridges, courthouses, and schools. The Civilian Conservation Corps (CCC) provided jobs to people willing to work towards reforestation of cut-over timber land and was the progenitor organization of the Allegheny National Forest. A number of CCC camps and CCC associated property types are located within the Forest including planted red pine plantations, including the first such effort at reforestation by the CCC in the United States.

The Conservation period is also the period when the U.S. Army Corps of Engineers undertook the construction of a number of large scale impoundments which flooded some of the region's best farm land to provide flood control, produce electrical power, and encourage the development of a recreation and tourist industry. The damming of rivers also produced a backlash effect that spawned the creation of a new conservation concept: national and scenic rivers -- and the Allegheny River was added to the Wild and Scenic River system. On a state level, the state park system was inaugurated at this time as well as the State Forests and Game and Fish Commission.

Although on a national, regional, and local scale, the wood products industry is not as extensive as it was during the Railroad Logging period, during the Conservation period its mode of transportation shifted to trucks. Unlike a number of other areas of the country where there was a "cut out and get out" strategy, through sustainable forestry practices, the wood products industry continues to be an important part of the regional economy. The regional heritage of this industry began with the construction of a sawmill by a prominent Seneca Indian Chief in 1800 and two centuries later continues to the present day.

The petroleum industry on the ANF in the Conservation period has changed dramatically from its beginning in the Oil Boom period. In its heyday during the latter period, over 90 percent of the world's oil supply was being produced from the oil fields in the region (Ross 1996). During the Oil Boom period, thousands of wells in dozens of historic oil fields were drilled. Beyond the effect to the environment that the exploration, extraction and refining had to the landscape of the ANF, the thousands of people who poured into the region to seek employment in the oil patch also had long-lasting effects. Boom towns grew overnight and were gone as quickly. What with the exploration and exploitation of substantially larger oil fields elsewhere in the world, the focus of the industry shifted away from the region to richer fields elsewhere in the country and around the world. The regional oil and gas industry today produces a very small percent of the overall supply of this resource to the world. The manner with which they explore and extract the resource has also undergone change during the Conservation period.