introduction - Pennsylvania Natural Heritage Program

Discussion and RecommendationsStatus of natural features todayThe landscape and waterways of ClearfieldCounty have undergone considerable changeover the course of human settlement, mostnotably from timber extraction, mining, andagriculture. During the timber boom in the earlytwentieth century, almost the entire landscape ofthe county underwent general clear-cutting, andsubsequently there were widespread fires.Mining began with deep mine excavation, andtransitioned to mostly strip mining operations asmining technology developed. Strip mining hasbeen extensive, resulting in an environmentaltransformation of a large proportion of thecounty land. Another legacy of mining iswidespread water pollution that seriouslyimpairs aquatic ecosystems in many of thecounty’s waterways. Throughout the county, thecondition of ecological resources today closelyreflects the history of human land use.Although mining and timber extraction remainprevalent in the county, natural communitieshave redeveloped across large swaths of thelandscape previously used for timber extraction,coal mining, and clay mining. Especially in thenorthern part of the county, there are large areasof contiguous forest that provide abundanthabitat for forest dwelling species. ClearfieldCounty spans several major regional topographictransitions—with the Allegheny Front boundingthe western edge of the county, the extremenorthern end of the Allegheny Mountainsterminating in the southeastern part of thecounty, and an extension of the High AlleghenyPlateau across the northern part of the countytransitioning into rolling low plateau landscapeto the west and into the West BranchSusquehanna River valley to the south. Theforest ecosystems historically present reflectedthis position at the juncture of three ecoregions:the high-elevation northern areas were similar inecological composition to the High AlleghenyPlateau, the southeast had mesophyticinfluencedforests, and the northwest was anextension of the Western Allegheny Plateaucommunities.Today the condition of forest communitiesvaries across the county. While many areasxihave re-grown and redeveloped a broadecological spectrum of natural forestcommunities, some areas are fragmented byroads, surface mined areas, artificial clearings,or utility rights-of-way. The character andquality of forested areas also reflects variabletimber management practices, with some areasless sustainably managed to date than others.Over-browsing by deer poses a threat tobiological diversity and forest regeneration inmany regions of the county. Of the threeecoregions in the county, the High AlleghenyPlateau has the greatest area of relatively intactforest, while the mesophytic-influenced and theWestern Allegheny Plateau portions of thecounty are more fragmented, with fewer wellrecoveredexamples of typical forestcommunities.However, despite the variable condition of theforests, their contiguity is a great asset to thecounty’s ecological integrity and is regionallyimportant in sustaining mid-atlantic populationsfor many animal species. Contiguous forestedareas offer enhanced habitat value overfragmented forested areas. While a number ofgeneralist species can succeed and reproduce insmall patches of forest, many species can onlyutilize large, unbroken tracts of forest. Becausemany of the forested areas in Clearfield Countytoday are large, contiguous patches, they supportspecies which are declining in other areas of thestate and the continent due to lack of habitat.The forests of Clearfield County have thepotential for even greater significance tobiodiversity in the future. Some species canonly find appropriate habitat in old-growthforests, because the structures they need forshelter or the food sources they require are notpresent in younger forests. While there are fewareas in Clearfield County today that are oldgrowth, the large expanses of younger forestsprovide the potential for the future development— in ecologically strategic areas — of prime oldgrowth habitat that can host species that aretoday in decline throughout the continent due tolack of habitat.Within the matrix of forest in the county, uniquecommunities including vernal pools, forestedseepage wetlands, headwaters shrub swamps,sandstone rockhouses, and calcareous rock