IDENTIFIERS

Current Taxon Name (Soil Name): Atwell

OSD

Series Extent

User Site ID: S1981CA605REDW003

User Pedon ID: S10CA023013

Vegetation Plot ID: S1981CA605REDW003

Lab Information:

Certified Lab Pedon Description - no

Lab Source ID - SSL

Lab Pedon # - 10N0684

NCSS Pedon Lab Data NASIS Record ID - 43152

Print Date: 1/30/2025

LOCATION

Location In Web Soil Survey

AOI is roughly a square mile and pedon is marked in the center.

Location in SoilWeb

Location in Google Maps

Std. Latitude: 41.2310371

Std. Longitude: -123.9972839

Datum: WGS84

Township: 10N

Range: 2E

Section: 30

PLSS Details: southeast quarter, northwest quarter

Location Description: Redwood National Park, Humboldt County, California; located approximately 61 meters north of Miller Creek, 49 meters west of C-road.

Map Unit: 531—Atwell-Coppercreek complex, 30 to 50 percent slopes

State: California

County: CA023—Humboldt

MLRA: 4—California Coastal Redwood Belt

Non-MLRA Soil Survey Area: CA605—Humboldt and Del Norte Area, California

7.5 Minute USGS Quad: 41123-B8—Bald Hills, California

PEDON

Describers Name: Jim Popenoe

Current Taxonomic Class: Fine, mixed, active, isomesic Oxyaquic Hapludalfs

Current Taxon Kind: series

Pedon Type: OSD pedon

Pedon Purpose: full pedon description

Pedon Record Orgin: NASIS

Pedon #: 13

Correlated Information:

Soil Name - Atwell

PSC - 29 to 79 cm.

Classificaton Date - 4/12/2010

Soil Taxonomic Edition - eighth edition

Moisture Class - udic

Moisture Subclass - oxyaquic

Sampled As Information:

Soil Name - Atwell

Taxonomic Class - Fine, mixed, active, isomesic Oxyaquic Hapludalf

Taxon Kind - series

Classificaton Date - 4/13/1981

Dynamic Soil Properties:

Erosion Class - 0

Pedoderm Loose Cover Indicator - no

Hydric: no

SITE

Parent Material: earthflow deposits derived from sandstone and shale

Landscape: mountains

Landform: earthflow on mountain slope

Geomorphic Component Mountains: mountainflank, lower third

Hill Slope Profile: backslope

Slope Complexity: simple

Slope Shape Across: linear

Slope Shape Down: linear

Runoff: medium

Drainage Class: moderately well

Flooding: none flooding

Ponding: none ponding

Wet Soil Moisture Duration: 30

Bedrock: sandstone and shale

Geology: Franciscan Formation formation.

Surface Fragments:

Benchmark Soil?: no

VEGETATION

SITE OBSERVATION

Observation Date: 4/13/1981 (actual site observation date)

Air Photo ID: 7-48

Surface Water Kind: none observed

Plant Association Name: Redwood Forest

Surface Cover Properties:

Site Obs. Cover Kind 1 - tree cover

Site Obs. Cover Kind 2 - conifers

Pedoderm Loose Cover Indicator - no

Drained? - no

Bedded Soil? - no

Forest Plantation? - no

Vegetation Plot Plants
Plant Symbol	Scientific Name	National Vernacular Name	Plant Type Group	Canopy Cover %	Vegetation Stata Level
LIDE3 VAOV2 SESE3 PSME TSHE ABGR RHODO VAPA MANE2 GASH POMU OXOR BLSP VISE3 TROV2	Lithocarpus densiflorus Vaccinium ovatum Sequoia sempervirens Pseudotsuga menziesii Tsuga heterophylla Abies grandis Rhododendron Vaccinium parvifolium Mahonia nervosa Gaultheria shallon Polystichum munitum Oxalis oregana Blechnum spicant Viola sempervirens Trillium ovatum	tanoak California huckleberry redwood Douglas-fir western hemlock grand fir rhododendron red huckleberry Cascade barberry salal western swordfern redwood-sorrel deer fern evergreen violet Pacific trillium	— — — — — — — — — — — — — — —	— — — — — — — — — — — — — — —	— — — — — — — — — — — — — — —

Pedon Diagnostic Features
Feature Kind	Feature Depth L-H	Feature Thickness L-RV-H
	cm
mollic epipedon argillic horizon aquic conditions	5—29 17—81 81—205	—24— —52— —124—

Setting and Climate
Slope	Slope Length USLE	Upslope Length	Elev.	Corr. Elev	Aspect	MAP	REAP	FFD	MAAT	MSAT	MWAT	MAST	MSST	MWST	MFFP	PE Index	Climate Station ID	Climate Station Name	Climate Station Type
%	m				degrees	mm	mm		C						mm
30	—	—	213	—	240	2160	—	285	12	14	9	—	—	—	—	—	—	—	—

Oi—0 to 5 centimeters (0.0 to 2.0 inches); slightly decomposed plant material; fragments.; moist when described; observed in pit, small

A—5 to 17 centimeters (2.0 to 6.7 inches); dark brown (10YR 3/3) broken face, grayish brown (10YR 5/2) broken face, dry; silt loam; 25 percent clay; moderate very fine subangular blocky, and moderate medium granular structure; firm, slightly sticky, slightly plastic; moderately slow permeability; 10.0 very fine roots and 4.0 medium roots and 10.0 fine roots; 10.0 fine irregular pores; 10 percent by volume moderately coherent cemented 2-38-75 millimeter sandstone-shale fragments; noneffervescent; slightly acid, pH 6.5, hellige-truog; clear wavy boundary. Lab sample # 10N03127; moist when described; observed in pit, small

AB—17 to 29 centimeters (6.7 to 11.4 inches); brown (10YR 4/3) broken face, brown (10YR 5/3) broken face, dry; clay loam; 33 percent clay; moderate medium subangular blocky structure; firm, moderately sticky, slightly plastic; moderately slow permeability; 4.0 very fine roots and 4.0 medium roots and 4.0 fine roots and 0.5 coarse roots; 4.0 very fine tubular and 4.0 fine irregular pores; 10 percent by volume moderately coherent cemented 2-38-75 millimeter sandstone-shale fragments; noneffervescent; moderately acid, pH 6.0, hellige-truog; clear wavy boundary. Lab sample # 10N03128; moist when described; observed in pit, small

BAt—29 to 59 centimeters (11.4 to 23.2 inches); dark yellowish brown (10YR 4/4) broken face, yellowish brown (10YR 5/4) broken face, dry; clay loam; 35 percent clay; moderate coarse subangular blocky parts to moderate medium subangular blocky structure; firm, moderately sticky, moderately plastic; moderately slow permeability; 4.0 very fine roots and 10.0 medium roots and 4.0 fine roots and 4.0 coarse roots; 4.0 very fine tubular and 4.0 medium tubular and 4.0 fine tubular and 0.5 fine irregular pores; 37 percent faint clay films on all faces of peds; 10 percent by volume moderately coherent cemented 2-38-75 millimeter sandstone-shale fragments; noneffervescent; moderately acid, pH 6.0, hellige-truog; clear irregular boundary. Lab sample # 10N03129; moist when described; observed in pit, small

Bt—59 to 81 centimeters (23.2 to 31.9 inches); light olive brown (2.5Y 5/4) broken face, pale yellow (2.5Y 7/4) broken face, dry; very gravelly clay loam; 50 percent clay; moderate medium subangular blocky structure; firm, moderately sticky, very plastic; very slow permeability; 4.0 very fine roots and 4.0 fine roots; 0.5 very fine tubular and 0.5 fine tubular pores; 15 percent distinct clay films on all faces of peds; 35 percent by volume moderately coherent cemented 2-38-75 millimeter sandstone-shale fragments; noneffervescent; moderately acid, pH 6.0, hellige-truog; clear wavy boundary. Lab sample # 10N03130; wet when described; observed in pit, small

2Cg1—81 to 103 centimeters (31.9 to 40.6 inches); greenish gray (5GY 5/1) broken face, light gray (N 7/), broken face, dry; clay; 50 percent clay; structureless massive; firm, moderately sticky, very plastic; very slow permeability; 0.5 very fine roots and 0.5 fine roots; 0.5 very fine tubular and 0.5 fine tubular pores; 25 percent medium prominent strong brown (7.5YR 5/6), moist, and reddish yellow (7.5YR 6/6), dry, masses of oxidized iron in matrix and 75 percent greenish gray (5GY 5/1), moist, and light gray (N 7/), dry, reduced matrix in matrix; 10 percent by volume moderately coherent cemented 2-38-75 millimeter sandstone-shale fragments; noneffervescent; moderately acid, pH 6.0, hellige-truog; clear smooth boundary. Lab sample # 10N03131; wet when described; observed in pit, small

2Cg2—103 to 155 centimeters (40.6 to 61.0 inches); dark bluish gray (5B 4/1) broken face, gray (N 6/), broken face, dry; clay; 50 percent clay; structureless massive; very firm, moderately sticky, very plastic; very slow permeability; 0.5 very fine roots and 0.5 fine roots; 0.5 very fine tubular and 0.5 fine tubular pores; 15 percent medium prominent yellowish brown (10YR 5/4), moist, and brownish yellow (10YR 6/6), dry, masses of oxidized iron in matrix and 85 percent dark bluish gray (5B 4/1), moist, and gray (N 6/), dry, reduced matrix in matrix; 10 percent by volume moderately coherent cemented 2-38-75 millimeter sandstone-shale fragments; noneffervescent; slightly acid, pH 6.5, hellige-truog; diffuse smooth boundary. Lab sample # 10N03132; wet when described; observed in pit, small

2Cg3—155 to 205 centimeters (61.0 to 80.7 inches); black (5Y 2.5/1) broken face, gray (N 5/), broken face, dry; clay; 50 percent clay; structureless massive; very firm, moderately sticky, very plastic; very slow permeability; 0.5 very fine roots and 0.5 fine roots; 0.5 very fine tubular and 0.5 fine tubular pores; 70 percent slickensides (pedogenic); 15 percent medium prominent yellowish brown (10YR 5/4), moist, and brownish yellow (10YR 6/6), dry, masses of oxidized iron in matrix and 85 percent black (5Y 2.5/1), moist, and gray (N 5/), dry, reduced matrix in matrix; 10 percent by volume moderately coherent cemented 2-38-75 millimeter sandstone-shale fragments; noneffervescent; slightly acid, pH 6.5, hellige-truog.; wet when described; observed in pit, small