Natural Resources
Conservation Service
Ecological site F130AY007PA
Fine To Loamy Mixed Metamorphic Floodplain
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): 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 Fine to Loamy Mixed Metamorphic Floodplain
ecological site occurs within both 66b, EPA Ecoregion IV – Northern Sedimentary and Metasedimentary Ridges, and in 66a - Northern
Igneous Ridges (Woods et. al., 1996).
Central Appalachian River Floodplain System - CES202.608
• Liriodendron tulipifera - Platanus occidentalis - Betula lenta / Lindera benzoin / Circaea lutetiana ssp. canadensis Forest Association –
CEGL006255
Central Appalachian Stream and Riparian System - CES202.609
• Platanus occidentalis - Betula nigra - Salix (caroliniana, nigra) Floodplain Forest Association - CEGL003896
(NatureServe 2017)
Ecological site concept
The Fine to Loamy Mixed Metamorphic Floodplains ecological sites are located on stream terraces, floodplains, and alluvial fans, on the eastern and western edges of the Northern Blue Ridge Region. The parent material is recent alluvium weathered from granite, gneiss, schist, phyllite, sandstone, siltstone, shales or other mixed metamorphic and crystalline rocks. Soils are deep, mostly well drained, and are strongly to slightly acidic. This ecological site occurs on active floodplains which differentiates it from similar bottomlands and footslope areas like the Mixed Metamorphic-Metabasalt Footslopes and Terraces and the Quartzitic Footslopes and Terraces which generally do not flood.
The reference forest state is a combination of several vegetation communities within the Central Appalachian Stream and Riparian and Central Appalachian River Floodplain Systems as defined by NatureServe (NatureServe 2009). These areas will have a mixture of oak and
hickory species characteristic of dry to mesic conditions, mesophytic (moisture loving) hardwood and hemlock forests, and typical floodplain species like sycamore, maple, and ash. Some of the highly variable coarse to fine textured depositional bars will host an early successional community of shrubs and woodlands and pockets of wetland plants. As a result of the somewhat gentler and flatter topography, the easier accessibility, and the better fertility and moisture content of alluvial soils, much of these areas have been settled, logged, and cleared relative to the steeper, drier, less fertile uplands. Therefore, mature forests may reflect the current naturalized, minimally managed post disturbance state rather than the forest composition of historic pre-European settlement. Approximately 16 percent of this ecological site has been converted to agricultural use, mainly pasture and hayland (Landfire 2013).
Associated sites
F130AY005PA |
Mixed Metamorphic - Metabasalt Footslopes And Terraces The Mixed Metamorphic-Metabasalt Footslopes and Terraces are on nearby slopes. |
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F130AY006PA |
Quartzitic Footslopes And Terraces The Quartzitic Footslopes and Terraces are on nearby 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 seep areas in and around the floodplains. |
Similar sites
F147XY009PA |
Loamy Mixed Floodplain The Loamy Mixed Floodplain provisional ecological site of the adjacent Ridge and Valley major land resource area has similar soil textures, depth, and drainage, and a history of human disturbance. Future field work and analysis may result in these ecological sites being combined. |
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Table 1. Dominant plant species
Tree |
(1) Liriodendron tulipifera |
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Shrub |
(1) Lindera benzoin |
Herbaceous |
(1) Circaea lutetiana |
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