LOCATION LACKSCREEK              CA

Established Series
Rev: JHP/JPS/ET
10/2016

LACKSCREEK SERIES

The Lackscreek series consists of moderately deep, well drained soils formed in colluvium and residuum derived from sandstone, mudstone, and schist. Lackscreek soils are on mountains and have slopes of 15 to 75 percent. The mean annual precipitation is about 2160 millimeters (85 inches) and the mean annual temperature is about 11 degrees C (52 degrees F).

TAXONOMIC CLASS: Loamy-skeletal, mixed, active, isomesic Typic Haplohumults

TYPICAL PEDON: Lackscreek very gravelly loam - on a convex south-facing slope of 65 percent under tanoak, Douglas fir, redwood, alder, coyotebrush, pampas grass, and yarrow at 279 meters (850 feet) elevation. (Colors are for moist soil unless otherwise noted. When described July 28, 2004, the soil was moist throughout.)

A--0 to 13 centimeters (0 to 5 inches); brown (10YR 4/3) very gravelly loam, pale brown (10YR 6/3) dry; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, medium and very coarse roots; many very fine and fine irregular and many very fine and fine and common medium tubular pores; 40 percent gravel and 1 percent cobbles; very strongly acid (pH 4.6); clear wavy boundary. (6 to 41 centimeters thick)

BAt--13 to 42 centimeters (5 to 17 inches); dark yellowish brown (10YR 4/4) very gravelly loam, light yellowish brown (10YR 6/4) dry; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; moderately few very fine, common fine and medium roots; many very fine and fine irregular and common very fine, fine, medium and very coarse tubular pores; very few faint clay films on ped faces; 50 percent gravel and 2 percent cobbles; very strongly acid (pH 4.5); clear wavy boundary. (0 to 30 centimeters thick)

Bt--42 to 70 centimeters (17 to 28 inches); dark yellowish brown (10YR 4/4) extremely gravelly loam, light yellowish brown (10YR 6/4) dry; weak medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine, common very fine and fine roots; many very fine and fine irregular and common fine, medium, coarse and very coarse tubular pores; very few faint clay films on ped faces; 55 percent gravel and 5 percent cobbles; very strongly acid (pH 4.6); clear wavy boundary. (15 to 85 centimeters thick)

BC--70 to 100 centimeters (28 to 40 inches); yellowish brown (10YR 5/6) extremely gravelly loam, very pale brown (10YR 7/4) dry; weak medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; common fine and medium roots; many very fine and fine irregular and common medium, coarse, and very coarse tubular pores 50 percent gravel, 15 percent cobbles and 1 percent stones; very strongly acid (pH 4.6); abrupt wavy boundary. (0 to 25 centimeters thick)

R--100 centimeters (40 inches); strongly cemented fractured sandstone, fractures mostly 10 to 45 centimeters apart.

TYPE LOCATION: Redwood National & State Parks, Del Norte County, California; near end of L87 Road; northwest quarter, northeast quarter, Section 7, T 15 N., R. 1 E. WGS84 Decimal degrees 41.71311 latitude and
-124.1041667 longitude; HBLM; USGS Childs Hill Quadrangle; UTM Zone 10 408144mE 4618515mN; NAD83.

RANGE IN CHARACTERISTICS:

Soil Moisture: The soil is usually moist in all parts in the soil moisture control section in most years, but becomes nearly dry in the upper part from about September 15 to October 15 in most years. The soils have an Udic moisture regime.

Soil Temperature: The mean annual soil temperature is 10 to 13 degrees C (50 to 55 degrees F). The difference between mean summer and mean winter temperature is 2 to 4 degrees C.

Depth to a lithic contact: 50 to 102 centimeters.
Organic Matter: There is 12 to 20 Kg per square meter of organic carbon above the lithic contact.
Reaction is moderately or strongly acid throughout. Base saturation is 15 to 35 percent at the lithic contact.
Surface fragments: 0 to 20 percent gravel and 0 to 10 percent cobble
Particle-Size Control Section (weighted average):
Rock fragments: 35 to 65 percent gravel and 0 to 35 percent cobbles.
Clay content: 23 to 35 percent clay.

Some pedons have O horizons.

O horizon

Hue: 10YR.
Value: 2 through 6 dry and moist.
Chroma: 1 through 4 dry and moist.
Texture: slightly decomposed organic material.
Wood fragments: 0 to 35 percent.
Reaction: moderately to very strongly acid.

A horizon

Hue: 7.5YR or 10YR.
Value: 3 through 5 dry, 2 through 4 moist.
Chroma: 3 or 4 dry, 2 through 4 moist.
Texture of fine earth: loam.
Rock fragments: 20 to 50 percent gravel and 0 to 5 percent cobbles.
Clay content: 18 to 27 percent.

Bt horizon

Hue: 7.5YR or 10YR.
Value: 5 through 7 dry, 3 through 5 moist.
Chroma: 4 through 6 dry and moist.
Texture of fine earth: loam, or clay loam.
Rock fragments: 30 to 65 percent gravel and 0 to 35 percent cobbles.
Clay content: 25 to 35 percent.

Some pedons have a C horizon.

C horizon

Hue: 7.5YR, 10YR, or 2.5Y.
Value: 5 through 7 dry, 4 through 6 moist.
Chroma: 4 through 6 dry and moist.
Texture of fine earth: loam or clay loam.
Rock fragments: 30 to 65 percent gravel, 5 to 35 percent cobbles, 0 to 1 percent stones.
Clay content: 20 to 35 percent.

COMPETING SERIES: At this time there are no other series in this family.

GEOGRAPHIC SETTING: Lackscreek soils are on strongly convex mountain slopes in highly dissected terrain and on narrow ridges. Slopes are 15 to 75 percent. Elevations are 19 to 926 meters (60 to 3040 feet). The soils formed in colluvium and residuum derived from sandstone, mudstone, and schist. The climate is humid with cool, foggy summers and cool, rainy winters. Mean annual precipitation is 1780 to 2550 millimeters (70 to 100 inches). Mean January temperature is about 8 degrees C; mean July temperature is about 14 degrees C; and the mean annual temperature is 10 to 13 degrees C (50 to 55 degrees F). Frost-free season is about 220 to 300 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ahpah, Coppercreek and Slidecreek soils. Ahpah and Coppercreek soils have less than 35 percent rock fragments in the particle-size control section. Coppercreek and Slidecreek soils are more than 100 centimeters (40 inches) deep to bedrock. The Ahpah soils are on gentler slopes, softer bedrock, or higher positions than the Lackscreek soils. The Coppercreek and Slidecreek soils are on straight to gently concave slopes, often below the Lackscreek soils.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high to very high runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: This soil has been used for commercial timber, recreation, wildlife, and watershed. Natural vegetation consists of Douglas fir, redwood, tanoak, madrone, and evergreen huckleberry.

DISTRIBUTION AND EXTENT: California Coastal Redwood Belt; MLRA 4B. The series is not extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Humboldt Del Norte area, California 2007. Source of name is from Lacks Creek, a major tributary to Redwood Creek about 24 kilometers east of the town of Trinidad.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

1. Ochric epipedon - the zone from 0 to 42 centimeters (A horizon)
2. Argillic horizon - the zone from 42 to 70 centimeters (BAt & Bt horizons)
3. Lithic contact - the bedrock interface at 102 centimeters
4. Particle-size control section - the zone from 42 to 70 centimeters, averages 23 percent clay, by weight, and 60 percent rock fragments, by volume.

Additional Data: NASIS User Pedon ID: 02CA605REDW068
The type location was changed in 2006 to better reflect the series concept.

Soil classified using the 12th Edition of the Keys to Soil Taxonomy.

---

National Cooperative Soil Survey
U.S.A.