LOCATION LEMPIRA OREstablished Series
TAXONOMIC CLASS: Medial, amorphic, frigid Typic Hapludands
TYPICAL PEDON: Lempira gravelly loam-forested, on a north-facing slope of 48 percent at an elevation of 3570 feet. (Colors are moist unless otherwise stated.)
Oi--1/2 inch to 0; slightly decomposed leaves, needles and twigs.
A1--0 to 4 inches; very dark grayish brown (10YR 3/2) gravelly loam, dark grayish brown (10YR 4/2) dry; moderate fine granular structure; slightly hard, friable, nonsticky and nonplastic; many very fine and fine and common medium and coarse roots; many very fine irregular pores; 15 percent gravel; very strongly acid (pH 4.6); clear smooth boundary. (3 to 10 inches thick)
A2--4 to 14 inches; dark brown (10YR 3/3) gravelly loam, brown (10YR 5/3) dry; moderate fine and medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine and common medium and coarse roots; many very fine irregular pore; 15 percent gravel; very strongly acid (pH 4.6); clear wavy boundary. (5 to 17 inches thick)
A3--14 to 29 inches; dark brown (10YR 3/3) gravelly loam, brown (10YR 5/3) dry; moderate very fine and fine subangular blocky structure; slightly hard, friable, sticky and plastic; common very fine, fine, medium and coarse roots; common very fine tubular pores; 15 percent gravel; very strongly acid (pH 4.6); clear wavy boundary. (0 to 18 inches thick)
Bw1--29 to 46 inches; dark yellowish brown (10YR 3/4) gravelly loam, light yellowish brown (10YR 6/4) dry; moderate very fine and fine subangular blocky structure; slightly hard, friable, sticky and plastic; common very fine, fine and medium roots; common very fine tubular pores; 15 percent gravel; very strongly acid (pH 4.6); clear smooth boundary. (10 to 26 inches thick)
Bw2--46 to 60 inches; dark yellowish brown (10YR 3/4) gravelly loam, light yellowish brown (10YR 6/4) dry; moderate fine and medium subangular blocky structure; slightly hard, firm, sticky and plastic; common very fine and fine roots; common very fine tubular pores; 30 percent gravel; very strongly acid (pH 4.6).
TYPE LOCATION: Douglas County, Oregon; 2 1/2 miles northeast of the junction of the South Fork and Middle Fork of Calapooya Creek; 2700 feet north and 300 feet west of the southeast corner of section 17, T. 24 S., R. 2 W., W.M. (Latitude 43 degrees, 29 minutes, 3 seconds N, Longitude 122 degrees, 57 minutes, 6 seconds W)
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to 60 inches or more. The mean annual soil temperature is 42 to 47 degrees F. The soil is usually moist and is dry within all parts of the moisture control section for less than 45 consecutive days following the summer solstice. The particle-size control section has a phosphate retention of 90 to 100 percent; acid oxalate extractable aluminum plus one-half iron of 2.0 to 4.0 percent; and 15-bar water on air-dried sample of 15 to 30 percent. The umbric epipedon is 20 to 45 inches thick.
The A horizon has value of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and dry. Rock fragments range from 15 to 30 percent gravel and 0 to 5 percent cobbles. It is moderately acid or very strongly acid. It has a moist bulk density of 0.75 to 0.90 grams per cubic centimeter. It has 2 to 10 percent organic matter and decrease to below 7 percent below a depth of 12 inches.
The Bw horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 5 to 7 dry and chroma of 3 or 4 moist and dry. It is gravelly loam, cobbly loam, loam, or clay loam with apparent clay content of 18 to 30 percent clay. Rock fragments range from 10 to 35 percent gravel and 0 to 15 percent cobbles. It has a moist bulk density of 0.85 to 1.00 grams per cubic centimeter. It is very strongly acid or strongly acid.
COMPETING SERIES: These are the Larchmount and Zynbar series. The Larchmount soils have sola less than 40 inches thick and have hue of 2.5YR or 5YR in the substratum. Zynbar soils are strongly acid or very strongly acid in the Bw horizon.
GEOGRAPHIC SETTING: Lempira soils are on hill slopes and plateaus. They formed in residuum and colluvium derived from basalt, andesite, and welded tuffs. Slopes are 3 to 60 percent. Elevations are 2,800 to 4,500 feet. The climate is characterized by cool, wet winters and cool, wet summers. The mean annual temperature is 40 to 45 degrees F, and the mean annual precipitation is 60 to 80 inches. The frost free period is 50 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Scaredman, Illahee, Mellowmoon, Thistleburn, and Telemon soils. Scaredman and Illahee soils are loamy-skeletal, and are on convex positions. In addition, Scaredman is moderately deep. Mellowmoon soils are fine-loamy. Thistleburn soils are fine textured with an argillic horizon. Telemon soils are somewhat poorly and moderately well drained, and are on concave positions.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: These soils are used for timber production, wildlife habitat, and watershed. The native vegetation includes western hemlock, Douglas fir and western redcedar with an understory of red huckleberry, vine maple, western princespine, American twinflower, violet, cascade Oregongrape, salal, western swordfern, Pacific trillium, Pacific rhododendron, and Oregon oxalis.
DISTRIBUTION AND EXTENT: Cascade mountains of southwestern Oregon. MLRA 3. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Douglas County, Oregon, 1994. The source of the name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Andic soil properties - throughout the soil and based on limited laboratory data from OSU. Hapludands based on not meeting organic carbon thickness requirement for melanic/fulvic; below 12 inches, organic carbon drops to below 4 percent.
Umbric epipedon - from the soil surface to 29 inches. (A1, A2, and A3 horizons)
Cambic horizon - from 29 to 60 inches. (Bw1 and Bw2 horizons)
Particle-size control section - from 0 to 40 inches. (A1, A2, A3, and part of the Bw1 horizon)
ADDITIONAL DATA: Reference samples 1984 and 1985; S84-OR-019 pedons 1 and 2; and S85-OR-019 pedons 1 and 2.