Ecological Associations of Ponderosa Pine Inside Jewel Cave National Monument, Custer, South Dakota

Mcdonald, Darrel

The objectives of this report are to determine the ecological relationships between forest habitats and the influence of soils and topography upon the distribution of forest habitats of Jewel Cave National Monument (JECA), Custer, South Dakota. The dominant forest species is ponderosa pine (Pinus ponderosa var. scopulorum). Within JECA's boundaries, natural and managed stands of different forest habitats can be delineated into three broad canopy cover classes (habitats) on aerial photos; 1) closed canopy (crowns touching), 2) open canopy (crowns not touching) and 3) parklands (grasses dominant). Soils vary inside JECA (Custer County Soil Survey 1983). Mapping forest cover types as a surrogate for forest habitats and comparing the resulting patterns to soil distributions, may reveal useful information about influence of soils upon the distribution of forest cover types in JECA. In addition, examination of data depecting the ecological nature of ponderosa pine habitats will provide information about the most significant influences upon pine forest habitats. JECA was established because of it's cave, but also because of the unique nature of the ponderosa pine forest found in that part of the Black Hills. Ponderosa pines of JECA are significant in that many of the trees found in part of the Monument are among the oldest and least exploited ponderosa pines to be found anywhere in the Black Hills. Pines dominate forest communities in this area (Daubenmire 1978). The forest inside JECA is different from surrounding forest tracts which have subject to commercial lumbering and grazing. As a result of exploration since 1900, cave passages have been discovered that extend beyond the original boundaries set for JECA. In 1965, there was a land exchange between the National Park Service and the U.S. Forest Service that brought the entire mapped network of the cave under National Park Service jurisdiction (Ditmanson 1983). The adjusted boundaries left only 160 acres of the original Monument still inside the newly defined JECA; a portion of the monument that has become known as the "historic area" (Figure 1). Vary federal management of the area encompassed by the JECA's boundaries, particularly with respect to the fire suppression program, makes the forest tract in the historic area a unique location in which to study the ecological implications of differing management policies upon ponderosa pine habitats. Patterns of forest cover and surface conditions can provide information about the effects of different management schemes on forest dynamics. Investigations of forest habitats and relationship to soils will provide basic geographic information for JECA. This type of comprehensive data is not presently available (Ditmanson 1983).