LOCATION SAWTOOTH                WA

Established Series
Rev. TMR/SBC
06/2011

SAWTOOTH SERIES

The Sawtooth series consists of moderately deep, well drained soils formed in volcanic ash overlying glacial drift and colluvium. Sawtooth soils are found on slopes of 0 to 60 percent on debris aprons, bedrock benches and valley walls of glaciated mountain landscapes. The mean annual precipitation is about 760 millimeters and the mean annual air temperature is about 7 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Andic Dystroxerepts

TYPICAL PEDON: Sawtooth gravelly ashy sandy loam, with approximately 40 percent of the soil surface covered with subangular cobbles, located on a forested south facing debris apron with a slope of 40 percent and an elevation of 560 meters. When described on June 29, 2007 the soil was dry throughout. (Colors are for moist soil unless otherwise noted)

Oi--0 to 3 cm; slightly decomposed plant material; common medium interstitial pores; abrupt wavy boundary.

A--3 to 15 cm; very dark brown (10YR 2/2) gravelly ashy sandy loam, dark yellowish brown (10YR 3/4) dry; weak coarse granular structure; soft, very friable, nonsticky, nonplastic; many very fine to fine, common medium to coarse roots; common fine to medium irregular pores; 5 percent fine gravel, 20 percent medium and coarse gravel, and 5 percent cobbles; strongly acid (pH 5.5); clear irregular boundary.

Bw1--15 to 35 cm; dark yellowish brown (10YR 3/4) gravelly ashy sandy loam, dark yellowish brown (10YR 4/6) dry; weak medium subangular blocky structure; soft, very friable, nonsticky, nonplastic; many very fine to coarse roots; common fine to medium irregular pores; 5 percent fine gravel, 20 percent medium and coarse gravel, and 5 percent cobbles; moderately acid (pH 5.8); clear irregular boundary.

2Bw2--35 to 45 cm; dark yellowish brown (10YR 3/6) gravelly sandy loam, dark yellowish brown (10YR 4/6) dry; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; common very fine to coarse roots; common fine to medium irregular pores; 5 percent fine gravel, 15 percent medium and coarse gravel, and 10 percent cobbles; moderately acid (pH 6.0); clear wavy boundary.

2BC--45 to 60 cm; dark olive brown (2.5Y 3/3) very cobbly loamy sand, light olive brown (2.5Y 5/4) dry; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; few very fine to medium roots around fragments; common fine to medium interstitial pores; 10 percent fine gravel, 15 percent medium and coarse gravel, and 30 percent cobbles; slightly acid (pH 6.1); abrupt irregular boundary.

2R--60 cm; metavolcanic bedrock.

TYPE LOCATION: Whatcom County, Washington; approximately 14 km south of the Hozomeen border crossing with Canada, above the east bank of Ross Lake, North Cascades National Park Service Complex; 180 meters west and 720 meters north of the southeast corner of section 7, T. 39 N., R. 14 E. Willamette Meridian; Hozomeen Mountain, Washington USGS quadrangle; 48 degrees, 52 minutes, 42 seconds north latitude and 121 degrees, 1 minutes, 20 seconds west longitude; UTM 645005 meters E, 5415840 meters N, zone 10N.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature 5 to 8 degrees C. Frigid soil temperature regime.
Moisture control section - dry 60 to 90 consecutive days. Xeric soil moisture regime.
Particle-size control section:
Clay content - 0 to 10 percent
Rock fragments - 35 to 55 percent total, 15 to 45 percent fine to coarse gravel, 5 to 35 percent cobbles, 0 to 15 percent stones
Thickness of volcanic ash mantle (ashy textural modifier): 18 to 35 centimeters
Depth to bedrock (lithic contact): 50 to 100 cm from the mineral surface.

A horizon
Hue - 10YR or 7.5YR
Value - 2 to 3 moist, 3 to 4 dry
Chroma - 1 to 4 moist and dry
Fine earth texture - ashy SL or ashy FSL
Rock fragments - 0 to 30 percent total, 0 to 30 percent fine to coarse gravel, 0 to 15 percent cobbles
Volcanic glass - 35 to 80 percent
Reaction - strongly acid to moderately acid
Thickness - 5 to 20 centimeters

Bw horizon
Hue - 10YR or 7.5YR
Value - 3 to 5 moist, 4 to 6 dry
Chroma - 3 to 6 moist or dry
Fine earth texture - ashy SL or ashy FSL
Rock fragments - 0 to 30 percent total, 0 to 30 percent fine to coarse gravel, 0 to 15 percent cobbles
Volcanic glass - 15 to 70 percent
Reaction - moderately acid to strongly acid
Thickness - 15 to 30 centimeters

2Bw horizon
Hue - 10YR or 7.5YR
Value - 3 to 4 moist, 4 to 5 dry
Chroma - 3 to 6 moist or dry
Fine earth texture - SL, COSL, FSL
Rock fragments - 30 to 60 percent total, 15 to 45 percent gravel, 5 to 35 percent cobbles, 0 to 15 percent stones
Volcanic glass - 5 to 15 percent
Reaction - moderately acid to strongly acid
Thickness - 15 to 35 centimeters

2BC horizon
Hue - 2.5Y or 10YR
Value - 3 to 4 moist, 4 to 5 dry
Chroma - 2 to 4 moist or dry
Fine earth texture - LS, COSL, SL, LFS
Rock fragments - 35 to 60 percent total, 15 to 50 percent fine to coarse gravel, 5 to 35 percent cobbles, 0 to 15 percent stones
Volcanic glass - 5 to 15 percent
Reaction - slightly acid to moderately acid

COMPETING SERIES: These are the Bertolotti, Cliffdell, Deroux, Goode, Littlejohn, Mesahchie, Mountaineer, Pheeney, Pitcher, Roxer, Scotties, and Umpa series. Bertolotti, Cliffdell, Goode, Mesachie, Pitcher, and Roxer soils are very deep. Littlejohn soils are dry in the moisture control section for 45 to 60 consecutive days and contain angular andesite rock fragments. Mountaineer soils have an umbric epipedon. Pheeney soils have an umbric epipedon and contain angular andesite rock fragments. Scotties soils are deep (100 to 150 cm) to a lithic contact and contain angular sandstone rock fragments. Umpa soils have 10 to 20 percent clay in the particle-size control section, formed in pyroclastic material, and contain less than 5 percent volcanic glass.

GEOGRAPHIC SETTING: Sawtooth soils are found on slopes of 0 to 60 percent on debris aprons, bedrock benches and valley walls of glaciated mountain landscapes at elevations from 300 to 1,000 meters. They formed in volcanic ash overlying glacial drift and colluvium. The climate is characterized by warm, dry summers and cold, wet winters. Mean annual precipitation ranges from 500 to 1,800 millimeters. Mean annual air temperature ranges from 2 to 8 degrees C. Frost-free season is 75 to 110 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Despair, Farway, and competing Goode and Mesahchie soils. Despair soils are shallow (less than 50 cm) to a lithic contact and have andic soil properties throughout the profile. Farway, Goode, and Mesahchie soils are very deep. Farway soils have andic soil properties greater than 35 cm thick. Mesahchie soils have an umbric epipedon.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high saturated hydraulic conductivity.

USE AND VEGETATION: Sawtooth soils support wildlife habitat, recreation, and watershed drainage. Native vegetation includes Douglas-fir, ponderosa pine, bigleaf maple, vine maple, snowberry, Saskatoon serviceberry, pachistima, Cascade Oregon-grape, spreading dogbane, birch-leaved spirea, kinnikinnick, broadleaf star flower, common yarrow, and pinegrass.

DISTRIBUTION AND EXTENT: North Cascade Mountains, Washington. MLRA 3. Series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon.

SERIES ESTABLISHED: North Cascades National Park Service Complex, Whatcom County, Washington, 2011.

REMARKS: Diagnostic horizons and features recognized in this pedon include:
Particle-size control section - 28 to 60 cm (25 to 57 cm from the mineral surface)
Ochric epipedon - 0 to 18 cm (Oi, A, and upper 3 cm of the Bw1 horizon)
Andic soil properties - 3 to 35 cm (A and Bw1 horizons)
Cambic horizon - 15 to 45 cm (Bw1 and 2Bw2 horizons)
Lithologic contact - 60 centimeters

---

National Cooperative Soil Survey
U.S.A.