Little Sink Research Natural Area

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Little Sink Research Natural Area

Salem District , BLM

Willamette Valley Ecoregion

Cell(s):

Douglas fir-grand fir/vine maple-salal.
Slump pond at margin of valley, with aquatic beds and marshy shore

Access by primitive road and trails

The 32 ha Little Sink RNA exemplifies the diversity in the Douglas fir (Pseudotsuga menziesii) forest type on marine siltstone, with geologic disturbances including slumps and ponds (both perennial and intermittent). It is located on a northwest-facing slope in upper Teal Creek drainage, 19 km west of Dallas in Polk County, Oregon. Elevation ranges from 180 to 320 m over moderate to steep topography with frequent slump benches, scarps, and basins resulting from frequent mass soil movements. Soil series are Blackly-Kilowan. The maritime climate is characterized by cool, wet winters and warm, dry summers, with annual precipitation averaging 186 cm. The entire RNA is forested, except the open pond areas. The canopy is mainly Douglas fir, with scattered bigleaf maple (Acer macrophyllum) which is especially common around the ponds. Grand fir (Abies grandis) in also common but occurs as a minor species in the canopy. Characteristic shrub species in the understory are vine maple (Acer circinatum) and salal (Gaultheria shallon). Bigleaf maple and Douglas fir occupy the highly disturbed slump benches and scarps. Wetland species, including cattails (Typha latifolia), slough sedge (Carex obnupta), and duckweed (Lemna minor), are present around the ponds. Special status species include dotted water-meal (Wolffia columbiana) and Northern spotted owl (Strix occidentalis caurina). A report of Lobaria linita was in error and has not been documented at this site. The last major fire occurred between 1600 and 1700. An area northwest of the RNA was logged between 1930 and 1935. An extensive trail system around the slump ponds is used by the adjacent Camp Fire Girls Camp and college classes for study. A guide book is available by Glenn Hawk (1974): Little Sink Research Natural Area Supplement 4. Dr. Morris Johnson (Western Oregon State College) completed a plant inventory in 1980.