Cedar Flats RNA, located in Skamania County, Washington, occupies gentle benches along the Muddy River. Moderately steep slopes occur in the western corner of the 275 ha tract, and elevations range from 366 to 640 m. Old-growth stands of western red cedar (Thuja plicata), along with associated swamps and marshes, are the key features of the RNA. The shrub and herb layers are dominated by Acer circinatum and Polystichum munitum. Other marsh and swamp communities are found in seasonal or continuously wet areas. These areas are a mosaic of shrub- and herb-dominated stands with scattered red alder (Alnus rubra) and some conifers on hummocks. Douglas fir (Pseudotsuga menziesii) and western red cedar are the most common tree species in the natural area; however, western hemlock (Tsuga heterophylla), Pacific silver fir (Abies amabilis), grand fir, and western white pine (Pinus monticola) are also represented. Common hardwoods include red alder, bigleaf maple (Acer macrophyllum), and black cottonwood (Populus balsamifera ssp. trichocarpa). Old- and second-growth classes of Douglas fir dominate the bulk of the area. In old-growth stands, western hemlock and Pacific silver fir appear to be the climax species. The understories of the Douglas fir stands seem to reflect the wide range of environmental conditions in which they occur. In the southwestern corner, the understory is dominated by Gaultheria shallon, Acer circinatum, Berberis nervosa, and Achlys triphylla. Moister sites have predominantly herbaceous understories.

The edge of the RNA along the Muddy River was affected by a mudflow following the 1980 eruption of Mt. St. Helens. A permanent sample plot was established in the area following the mudflow.

Township/Range/Section:

Portions of secs 11, 12 and 13, T7N, R6E.

Latitude:

45,06N

Longitude:

122,01W

Quad Map:

15' Mt. St. Helens (1956) - scale 1:62,500.

Threatened or Endangered Species:

Exotic Species Present:

Plant Communities:

Old-growth stands of western red cedar and Douglas fir. Both forest and nonforest communities occur. Communities include: Douglas fir-western hemlock, western red cedar, and red alder. A variety of swamp and marsh communities occur.

Aquatic Features Present:

Cedar Creek runs into the RNA. Muddy River runs along the eastern edge. A swamp is located near the center of the RNA.

Soils:

Soil types belonging to Brown Podzolic, Sols Bruns Acides, Alluvial, and Humic Gley great soils groups were encountered during reconnaissance. Organic soils associated with some of the swamp and marsh land habitat.

Other Physical Features:

RNA occupies a gently undulating series of benches along the Muddy River.

Past Disturbance History:

Other Comments: