Natural Resources
Conservation Service
Ecological site F147XY006PA
Mixed Limestone Lower Slope
Last updated: 9/27/2024
Accessed: 11/21/2024
General information
Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
MLRA notes
Major Land Resource Area (MLRA): 147X–Northern Appalachian Ridges and Valleys
Major Land Resource Area 147 is in the Middle section of the Valley and Ridge Province of the Appalachian Highlands. Characteristic features include folded and faulted parallel ridges and valleys that are carved out of anticlines, synclines, and thrust blocks. The variability of weathering of the underlying bedrock has resulted in resistant sandstone and shale ridges separated by less resistant limestone and shale narrow to moderately broad valleys. The ridges are strongly sloping to extremely steep and have narrow, rolling crests, and the valleys are mainly level to strongly sloping. The Great Valley is a salient feature of the eastern portion and runs the entire length of the MLRA where it is called the Shenandoah Valley in the south. The western side of the MLRA is dominantly hilly to very steep and is rougher and much steeper than the rolling hills to the east. Parts of the northernmost section of the MLRA were subjected to pre-Illinoian glaciation (>770,000 years ago). Anthracite coal underlies some areas in the north and has been mined since the 1700’s.
Elevation in MLRA 147 generally ranges from 330 to 985 feet (100 to 300 meters) in the valleys and from 1,310 to 2,625 feet (400 to 800 meters) on the ridges and mountains. It is as high as 2,955 feet (900 meters) on some mountain crests and is nearly 4,430 feet (1,350 meters) on a few isolated, linear mountain ridges. Local relief in the valleys is about 15 to 165 feet (5 to 50 meters). The ridges rise about 660 feet (200 meters) above the adjoining valleys. (USDA, 2006).
Classification relationships
This ecological site is found in Major Land Resource Area 147- Northern Appalachian Ridges and Valleys, 148. MLRA 147 is located within Land Resource Region S - Northern Atlantic Slope Diversified Farming Region (USDA 2006), and in United States Forest Service ecoregion M221 – Central Appalachian Broadleaf Forest-Coniferous Forest-Meadow Province (Bailey, 1995). In addition, MLRA 147 falls within area #67 of EPA Ecoregion Level III – the Ridge and Valley (US EPA 2013). The Mixed Limestone Lower Slope ecological site occurs within 67a and 67b of EPA Ecoregion IV - Northern Limestone/Dolomite Valleys, and Northern Shale Valleys respectively (Woods et. al., 1996).
Ecological site concept
The Mixed Limestone Lower Slope ecological sites occur throughout MLRA 147 on lower slopes of hills within valleys on soil material derived from a mixture of limestone, calcareous shale, or mixed limestone and sedimentary geologies. These sites occur less commonly in mountains. They occupy positions on midslopes, footslopes, toeslopes, benches, depressions, drainageways, swales, fans, valley floors, and valley sides. Slopes are generally moderately to gently sloping and can be concave, planar, or slightly convex. Depth to bedrock is greater than 40 inches (100 cm) and most sites are moderately well to somewhat poorly drained with the seasonal high water table occurring between 10 to 48 inches (25 to 122cm). Dense subsurface soil layers called fragipans are characteristic of these landscapes. Fragipans impede the downward growth of tree roots and also prevent rapid drainage of water. Generally these sites are not subject to flooding or ponding. They have favorable moisture conditions for plant growth.
The majority of these areas are cleared for agricultural production. Existing woodland and forest generally contain Acer saccharum (Sugar maple) and Tilia Americana (American basswood) as the dominant canopy tree species. Fraxinus Americana (White ash) is frequent but not necessarily abundant. Acer rubrum (Red maple), Fagus grandifolia (American beech), and Prunus serotina (Black cherry) are typical associates. These mid to lower slope ecological sites are rich relative to the acidic shale and sandstone uplands, and contain more moisture compared to the Limestone uplands.
Associated sites
| F147XY003PA |
Mixed Limestone Upland Mixed Limestone Upland |
|---|
Table 1. Dominant plant species
| Tree |
(1) Acer saccharum |
|---|---|
| Shrub |
(1) Acer pensylvanicum |
| Herbaceous |
(1) Caulophyllum thalictroides |
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