LOCATION PUHIMAU HI
Established Series
Rev. KH-RTG
08/2012
PUHIMAU SERIES
The Puhimau series consists of very shallow and shallow, moderately well drained soils that formed in volcanic ash deposited over pahoehoe lava. Slopes range from 2 to 10 percent. The mean annual rainfall is about 2,489 millimeters (98 inches), and the mean annual air temperature is about 16 degrees C. (61 degrees F.)
TAXONOMIC CLASS: Ashy, amorphic, isothermic Lithic Hapludands
TYPICAL PEDON: Puhimau ashy silt loam under rain forest at an elevation of 1,128 meters (3,700 feet). (Colors are for moist soil unless otherwise noted. When described on 12/4/97 the soil was moist throughout. All textures are "apparent field textures". pH was determined by adjusting field organic dye values via regression to approximate pH in 1:1 water.)
A--0 to 8 centimeters (0 to 3 inches); lithochromic black (7.5YR 2.5/1) ashy silt loam; moderate medium subangular blocky structure parting to moderate fine granular; slightly hard, friable, slightly sticky and slightly plastic, weakly smeary; many very fine and fine roots; many very fine and fine interstitial and tubular pores; extremely acid (pH 4.3); abrupt wavy boundary. (2.5 to 10 centimeters (1 to 4 inches) thick)
Bw--8 to 14 centimeters (3 to 5.5 inches); 60 percent very dark brown (7.5YR 2.5/2) and 40 percent black (7.5YR 2.5/1) very extremely gravelly ashy loamy coarse sand; massive; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine interstitial pores; 60 percent subrounded pyroclastic gravel, half of which is 2- to 5-mm size; slightly acid (pH 6.3); abrupt wavy boundary. (2.5 to 13 centimeters (1 to 5 inches) thick)
C--14 to 20 centimeters (5.5 to 8 inches); lithochromic dark grayish brown (10YR 4/2) ashy loam; massive; slightly hard, friable, slightly sticky and nonplastic, weakly smeary; few very fine and fine roots; common very fine and fine interstitial pores; few fine distinct yellowish red (5YR 4/6) moist redox concentrations in root channels; 10 percent subrounded pyroclastic gravel; neutral (pH 6.6); abrupt irregular boundary. (2.5 to 10 centimeters (1 to 4 inches) thick)
2Bw--20 to 28 centimeters (8 to 11 inches); dark reddish brown (5YR 3/2) ashy silt loam; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic, weakly smeary; many very fine to coarse roots; many very fine and fine interstitial pores; few fine faint yellowish red (5YR 4/6) redox concentrations; 1/4 inch discontinuous black (N 2/0) band throughout horizon; 3 percent small fragments of placic-like material; neutral (pH 6.6); abrupt wavy boundary. (2.5 to 10 centimeters (1 to 4 inches) thick)
2C--28 to 33 centimeters (11 to 13 inches); dark grayish brown (10YR 4/2) ashy loam; massive; slightly hard, friable, slightly sticky and nonplastic; many very fine and fine roots; common very fine and fine interstitial and tubular pores; common fine prominent yellowish red (5YR 4/6) redox concentrations; neutral (pH 6.6); clear wavy boundary. (0 to 15 centimeters (0 to 6 inches) thick)
3R--33 centimeters (13 inches); hard pahoehoe bedrock.
TYPE LOCATION: Hawaii Volcanoes National Park; from main entrance drive south (left) on Crater Rim Drive and continue to Chain of Craters Road; turn south (left), follow Chain of Craters Rd to Mauna Ulu Trailhead turnoff; follow road 0.1 mile to escape access road; go through gate and travel 2.8 miles (past second gate at 2.65 miles); park at pull off to west; from west side of parking area head 220 degrees for approximately 6 meters (19 feet) to type location; Volcano Quadrangle; lat. 19 degrees 24 minutes 00 seconds N. and long. 155 degrees 13 minutes 10 seconds W. (Old Hawaiian Datum from USGS topo.)
RANGE IN CHARACTERISTICS:
Depth to bedrock: 5 to 50 centimeters (2 to 20 inches).
Mean annual soil temperature: 15 to 18 degrees C. (59 to 65 degrees F.)
Soil reaction: Very strongly acid to slightly acid.
Underlying horizons: 2C and 3C horizons occur in some pedons.
A horizon
Hue: 5YR, 7.5YR or 10YR.
Chroma: 1 or 2 moist.
Structure: Granular or subangular blocky.
Bw horizon
Hue: N, 7.5YR or 10YR.
Chroma: 1 or 2 moist.
Rock fragments: 45 to 60 percent gravel; more than half the gravel is 2-to 5-mm size in most pedons.
C horizon
Chroma: 1 or 2 moist.
2Bw horizon
Texture: Ashy fine sandy loam, ashy loam or ashy silt loam.
2C horizon
Chroma: 3 or 4 moist.
Value: 2 or 3 moist.
Placic material: Fragments of placic-like material occur in some pedons.
3C horizon (when present)
Hue: 5YR, 7.5YR or 10YR.
Value: 2 or 3 moist.
Chroma: 1 or 2 moist.
Texture: Ashy sand, ashy loamy coarse sand, ashy loamy sand, ashy fine sandy loam.
4C horizon (when present)
Texture: Coarse ashy sand.
Cinders: 65 to 90 percent cinders.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Material weathered from Kilauea Volcano's Keanakakoi eruption and subsequent surge and airfall pyroclastic deposits over pahoehoe lava. Puhimau soils are on pahoehoe flows less than 750 years old at elevations of 914 to 1,219 meters (3,000 to 4,000 feet). Slopes range from 2 to 10 percent. The mean annual rainfall is 2,032 to 3,048 millimeters (80 to 120 inches), with about 80 percent of the rainfall occurring between October and May. The mean annual pan evaporation is 1,397 to 1,651 millimeters (55 to 65 inches). The mean annual air temperature is 15 to 18 degrees C. (59 to 65 degrees F.)
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Manu and Lithic Hapludands soils. Manu soils are moderately deep and have a buried 6A horizon and a gleyed 8Cg horizon. Lithic Haplustands have an ustic moisture regime.
DRAINAGE AND PERMEABILITY: Moderately well drained. Runoff is very high. Permeability is rapid in the soil and very slow in the underlying pahoehoe bedrock.
USE AND VEGETATION: These soils are used for National Park Service land. Vegetation is `a`ali`i (Dodonaea viscosa), wawai`iole or club moss (Lycopodium cernuum), uluhe or false staghorn fern (Dicranopteris linearis), kawa`u or Hawaiian Holly (Ilex anomala), `ohelo (Vaccinium reticulatum), and hapu`u- pulu or tree fern (Cibotium glaucum).
DISTRIBUTION AND EXTENT: These soils occur within Hawaii Volcanoes National Park and adjoining State of Hawaii Lands, near Thurston Lava Tube; MLRA 161. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Island of Hawaii, Hawaii County, Hawaii, 1978.
REMARKS: Diagnostic horizons and features recognized in this horizon are:
Andic soil properties - from 8 to 33 centimeters (3 to 13 inches).
Lithic contact - at 33 centimeters (13 inches).
Soil temperature - mean summer and mean winter soil temperatures differ by less than 6 degrees C. (iso temperature regime).
Soil moisture - not dry in some or all parts for 90 days or more in most years (udic moisture regime).
Edit Log: 12/03 KH. Added "ashy" modifier to textures.
ADDITIONAL DATA: Puhimau NSSL sample S96HI-001-019. Did not sample type location.
Penetrometer measurements made by inserting penetrometer horizontally into "in situ" soil:
A horizon = <0.25 tons/square foot
Bw horizon - too much gravel to take reading
C horizon = 1.5 to 3.0 tons/square foot
readings decrease with depth
2Bw horizon = <0.25 tons/square foot
2C horizon = <0.5 tons/square foot
National Cooperative Soil Survey
U.S.A.