Natural Resources
Conservation Service
Ecological site F130AY008PA
Poorly To Somewhat Poorly Drained Floodplains And Toeslopes
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 Poorly to Somewhat Poorly Drained Mixed
Metamorphic Floodplain and Toeslope ecological site occurs within both 66b, EPA Ecoregion IV – Northern Sedimentary and
Metasedimentary Ridges, and in 66a - Northern Igneous Ridges (Woods et. al., 1996).
North-Central Interior and Appalachian Rich Swamp System - CES202.605 and
Central Appalachian Stream and Riparian System - CES202.609
Acer rubrum - Fraxinus nigra - Betula alleghaniensis / Veratrum viride - Carex bromoides Seep Forest association - CEGL008416
Acer rubrum - Nyssa sylvatica / Ilex verticillata - Vaccinium fuscatum / Osmunda cinnamomea Forest association - CEGL007853
Ecological site concept
The Poorly to Somewhat Poorly Drained Floodplains and Toeslopes ecological site of the Northern Blue Ridge region is located on footslopes of mountains and hills, depressions, drainageways, swales, and floodplains. This ecological site contains both colluvial (material
that has moved from higher slopes to lower ones) and alluvial material (sediments transported by water and deposited along floodplains).
The main characteristic of these landscapes is that they are usually in lower slope positions and many contain wetlands. The colluvial and alluvial materials are derived from a mixture of geologies including granite, gneiss, metabasalt, phyllite, quartzite, schist, sandstone,
siltstone, and shale.
The reference forest state is a combination of several vegetation communities within the North-Central Interior and Appalachian Rich Swamp, the North-Central Appalachian Acidic Swamp, and the Central Appalachian Stream and Riparian Systems as defined by
NatureServe (NatureServe 2009; Anderson et. al. 2013). Tree species may include hemlock, red maple, and sourgum where the underlying soil is acidic, or red maple and black ash where soil pH is closer to neutral. Drier areas may have hemlock and northern hardwood species such as sugar maple, yellow birch, and American beech.
Disturbance agents in these forests include wind throw and ice damage. Despite the poor drainage, at least 15 percent of this ecological site has been cleared for agricultural use, primarily pasture and hayland. Other human activity including logging and early settlement have resulted in at least 27% of the forests becoming mid successional. The composition of the pre-settlement forest is not certain.
Associated sites
F130AY005PA |
Mixed Metamorphic - Metabasalt Footslopes And Terraces The Mixed Metamorphic-Metabasalt Footslopes and Terraces are on nearby slopes. |
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F130AY007PA |
Fine To Loamy Mixed Metamorphic Floodplain The Fine to Loamy Mixed Metamorphic Floodplain occurs along nearby drainageways and streams. |
Table 1. Dominant plant species
Tree |
(1) Acer rubrum |
---|---|
Shrub |
(1) Veratrum viride |
Herbaceous |
(1) Carex bromoides |
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