Natural Resources
Conservation Service
Ecological site F130AY005PA
Mixed Metamorphic - Metabasalt Footslopes And Terraces
Last updated: 9/27/2024
Accessed: 11/13/2024
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): 130A–Northern Blue Ridge
Major Land Resource Area 130A is in the Northern Section of the Blue Ridge Province of the Appalachian Highlands. The region is characterized by rugged mountains with steep slopes, sharp crests, and narrow valleys. The mountain range forms a narrow band that runs north to south between the Piedmont Upland Section to the east, the Ridge and Valley section to the west, and the Southern Section of the Blue Ridge to the south. Stream dissection is deep and intricate. Major streams and their tributaries flow through gorges and gaps. Elevation ranges from about 820 feet (250 meters) in the lower valleys and on footslopes along the Potomac River just east of Harpers Ferry, where West Virginia joins Maryland and Virginia, to more than 4,200 feet (1,280 meters) along the Appalachian Trail in Bedford County, Virginia. Apple Orchard Mountain, the highest peak, is at an elevation of 4,225 feet (1,288 meters) (USDA 2006).
The backbone of the northern Blue Ridge is an anticline composed of rocks that can be can be divided into geological groupings based on age. In general, the oldest rocks are the furthest east, and become younger towards the west (Fichter and Baedke, 2000; Barnes and Sevon, 2002). The first group are plutonic rocks that formed when liquid molten rock, called magma, solidified deep within the earth’s crust over a billion years ago. Collectively referred to as the Grenville rocks, they make up much of the eastern half of the mountains and are composed of granites, gneisses, and granulites. The second group, characterized by the Catoctin greenstone formation, is slightly younger, and is made up of metabasalts and metarhyolites, types of igneous rocks that have been metamorphosed by heat and pressure. The third group was formed during the Cambrian period about 500 million years ago and are represented by the Harpers, Antiedam, Weverton, and Loudoun formations which comprise the Chilhowee group. These rocks are primariliy quartzites, phyllites, and meta-sandstones, and form the western flank of the Blue Ridge.
Preliminary ecological site differentiation is based on these three main age groups and geologies. The variable characteristics of the underlying rocks give rise to different soil physical and chemical properties and exert control on the landscape, slope shape, aspect, and elevation, all of which affect vegetation.
Classification relationships
This ecological site is found in Major Land Resource Area 130A – the Northern Blue Ridge. MLRA 130A is located within Land Resource Region N – East and Central Farming and Forest Region (USDA 2006), and in United States Forest Service ecoregion M221D – Central Appalachian Broadleaf Forest-Coniferous Forest-Meadow Province, Blue Ridge Mountain Province (Bailey, 1995).In addition, MLRA 130A falls within area #66 of EPA Ecoregion Level III – the Blue Ridge (US EPA 2013). The Mixed Metamorphic - Metabasalt Footslopes and Terraces ecological site occurs primarily within 66a - Northern Igneous Ridges (Woods et. al., 1996).
Northeastern Interior Dry-Mesic Oak Forest System - CES202.592
Liriodendron tulipifera - Pinus strobus - Tsuga canadensis - Quercus rubra / Polystichum acrostichoides Forest association - CEGL006304
Southern and Central Appalachian Cove Forest Systems - CES202.373
Tsuga canadensis - Quercus prinus - Liriodendron tulipifera / Kalmia latifolia - (Rhododendron catawbiense) Forest association - CEGL008512
(NatureServe 2017)
Ecological site concept
Mixed Metamorphic - Metabasalt Footslopes and Terraces ecological sites are found throughout the Northern Blue Ridge of the Appalachian Highlands on mountain footslopes, toeslopes, coves, benches, drainageways, mountain valleys, stream terraces, and fans. The underlying geology includes gneiss, granite, granodiorite, granulite, metabasalt, phyllite, schist, and some sandstone, and shale. Soils are deep, mostly well drained and generally acidic with low to moderate fertility. These low to mid slope areas will be deeper and hold more moisture than ecological sites further upslope. The Quartzitic Footslopes and Terraces ecological site is on similar landscapes, but the underlying bedrock is composed primarily of quartzites and metasandstones. These areas are drier, more acidic, and less fertile, and will include more pine and oak forest types. At least 15% of the Mixed Metamorphic-Metabasalt Footslope and Terraces ecological site has been converted to agricultural use verses approximately only 2 percent of the Quartzitic ecological site.
The reference forest state is a combination of several vegetation communities within the Northeastern Interior Dry-Mesic Oak Forest and the Southern and Central Appalachian Cove Forest Systems as defined by NatureServe (NatureServe 2009). These areas will have oak and hickory species characteristic of dry to mesic conditions as well as mesophytic (moisture loving) hardwood or hemlock-hardwood forests. Generally, the drier, convex, slopes will contain more oaks while the sheltered and concave lowest slope positions will be dominated by tuliptree, maple, hemlock, basswood, elm, birch, and beech. Vegetation varies according to soil chemistry. Disturbance agents in these forests include fire, wind throw, ice damage, human activity, and pests like gypsy moths and the woolly adelgid which heavily impact oak and hemlock species respectively.
Associated sites
F130AY001PA |
Mixed Metamorphic And Granitic Upland The Mixed Metamorphic and Granitic Uplands ecological site occurs on adjacent upper slopes. |
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F130AY002PA |
Metabasalt Upland The Metabasalt Uplands ecological site occurs on adjacent upper slopes. |
F130AY008PA |
Poorly To Somewhat Poorly Drained Floodplains And Toeslopes The Poorly to Somewhat Poorly Drained Floodplains and Toeslopes ecological site is on depressions, and slope break seep areas in and around the footslope and terrace landscapes. |
F130AY003PA |
Phyllite-Metasandstone Upland The Phyllite-Metasandstone Upland ecological site occurs on adjacent upper slopes. |
F130AY007PA |
Fine To Loamy Mixed Metamorphic Floodplain The Fine to Loamy Mixed Metamorphic Floodplain ecological site occurs along adjacent drainageways and streams. |
Similar sites
F147XY007PA |
Loamy To Coarse Terrace This provisional ecological site is similar to the Loamy to Coarse Terrace ecological site of Major Land Resource Area 147 – Northern Appalachian Ridges and Valley. Future analysis and field work may result in combining these ecological sites. |
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Table 1. Dominant plant species
Tree |
(1) Liriodendron tulipifera |
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Shrub |
Not specified |
Herbaceous |
(1) Polystichum acrostichoides |
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