LOCATION PUU OO                  HI

Established Series
Rev. HHS/RCH/PGN/MRK
05/2012

PUU OO SERIES

The Puu Oo series consists of deep, well drained soils that formed in material weathered from volcanic ash. Puu Oo soils are in ash fields on upper elevation, windward slopes of Mauna Kea and Mauna Loa volcanoes. Slopes range from 2 to 20 percent. Mean annual precipitation is about 2540 millimeters (100 inches) and mean annual temperature is about 13 degrees C (56 degrees F).

TAXONOMIC CLASS: Medial over hydrous, ferrihydritic, isomesic Acrudoxic Hydrudands

TYPICAL PEDON: Puu Oo medial silt loam, on an east facing 5 percent slope under pasture and an elevation of 1,871 meters (6140 feet). (Colors are for moist, crushed, soil unless otherwise noted)

A1--0 to 8 centimeters (0 to 3 inches); dark reddish brown (5YR 2.5/2) medial silt loam; dark reddish brown (5YR 3/2) crushed, dry; moderate fine granular structure; friable, soft, slightly sticky, slightly plastic and weakly smeary; many roots; many very fine pores; strongly acid (pH 5.4); clear smooth boundary.

A2--8 to 15 centimeters (3 to 6 inches); very dark gray (5YR 3/1) medial silt loam; very dark gray (7.5YR 3/1) crushed, dry; moderate fine subangular blocky structure; friable, soft, slightly sticky, slightly plastic and weakly smeary; many roots; many fine pores; fine pieces of black charcoal; very strongly acid (pH 4.5); abrupt smooth boundary. (combined thickness of the A horizons is 13 to 25 centimeters (5 to 10 inches))

2Bw1--15 to 23 centimeters (6 to 9 inches); dark reddish brown (5YR 3/3) hydrous silty clay loam; dark brown (7.5YR 3/3) crushed, dry; moderate fine subangular blocky structure; friable, soft, slightly sticky, slightly plastic and moderately smeary; many roots; many fine pores; extremely acid (pH 4.2); abrupt wavy boundary.

2Bw2--23 to 41 centimeters (9 to 16 inches); very dark brown (10YR 2/2) hydrous silty clay loam; very dark gray (10YR 3/1) crushed, dry; moderate fine subangular blocky structure; friable, soft, slightly sticky, slightly plastic and moderately smeary; many roots; many fine pores; very strongly acid (pH 4.8); abrupt smooth boundary.

2Bw3--41 to 56 centimeters (16 to 22 inches ); very dark brown (10YR 2/2) hydrous silty clay loam; very dark gray (10YR 3/1) crushed, dry; massive; friable, slightly hard, slightly sticky, soft, slightly plastic and strongly smeary; common roots; many fine pores; 10 percent subangular gravel sized, gibbsite nodules; very strongly acid (pH 5.0); abrupt smooth boundary.

2Bw4-- 56 to 69 centimeters (22 to 27 inches); very dark grayish brown (10YR 3/2) hydrous sandy clay loam; dark grayish brown (10YR 4/2) crushed, dry; moderate medium and fine subangular blocky structure; friable, soft, sticky, plastic and strongly smeary; common roots; many fine pores; very strongly acid (pH 5.0); abrupt smooth boundary. (combined thickness of the 2Bw horizon is 46 to 64 centimeters (18 to 25 inches thick))

3Cr--69 to 127 centimeters (27 to 50 inches); dark yellowish brown (10YR 3/4) hydrous very fine sandy clay loam; dark grayish brown (10YR 4/2) crushed, dry; massive; extremely firm, very hard, slightly sticky, nonplastic and weakly smeary; few roots; many fine pores; strongly acid (pH 5.3). (thickness of the 3Cr horizon is 50 to 75 centimeters (20 to 30 inches thick))

4R--127 centimeters (50 inches); highly weathered basalt

TYPE LOCATION: Island of Hawaii; from Keanakolu road (Mana Road) at Waipahoehoe gulch; hike approximately 1.2 miles due east following the north side of the gulch. The type location is 500 feet northeast of the gulch; Puu Akala Quadrangle 19 degrees 46 minutes 20 seconds North latitude and 155 degrees 20 minutes 25 seconds West longitude (Old Hawaiian Datum).

RANGE IN CHARACTERISTICS: Depth to bedrock: 100 to 150 centimeters (40 to 60 inches).
Depth to restrictive feature: 69 to 127 centimeters (27 to 50 inches)
Rock fragments: 0 to 20 percent by volume of the pedon and usually occur in the lower part they range from gravel to cobble size lava rocks.
Soil moisture: The soil is typically moist but there may be brief periods of dryness from 0 to 15 cm (0 to 6 inches) during the driest months of the year, usually June thru August.
Soil temperature: 8 to 14 degrees C (46 to 58 degrees F).

A horizon
Hue: 5YR to 10YR
Value: 2 or 3 moist.
Chroma: 1 through 3 moist.
Texture: Medial loam or medial silt loam.

2Bw horizons
Hue: 5YR to 10YR.
Value: 2 or 3 moist.
Chroma: 2 to 4 moist.
Mixed colors: often occur in the lower Bw horizons.
Texture: Hydrous loam, hydrous silt loam or hydrous silty clay loam.

3Cr horizons
Hue: 5YR to 10YR.
Value: 2 or 3 moist.
Chroma: 2 to 4 moist.
Texture: Hydrous very fine sandy loam, hydrous loam, hydrous silt loam, or hydrous silty clay loam.
Degree of cementation: weakly to strongly

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: The Puu Oo soils are soils are in ash fields that are on the upper-elevation windward slopes of Mauna Kea and Mauna Loa volcanoes at elevations of 1372 to 1981 meters (4,500 to 6,500 feet). Slopes are 2 to 20 percent. The soils formed in recent volcanic ash.Mean annual rainfall is 1270 to 3302 millimeters (50 to 130 inches). Mean annual soil temperature is 12 to 14 degrees C (54 to 57 degrees F).

GEOGRAPHICALLY ASSOCIATED SOILS: On Mauna Kea volcano, these are the Kau, Keamoku, Laumaia, Kaiwiki, and Waiakea soil series. Kau, Keamoku, and Waiakea soils all have greater than 35 percent rock fragments in the control section. Laumaia soils have cementation in 75 percent or more of the pedon. Kaiwiki soils are on elevations of less than 1615 meters (5300 feet).
On Mauna Loa volcano, these are Puali, Pahipa, and Kaholimo. Puali and Kaholimo soils are less than 50 centimeters (20 inches) deep to pahoehoe lava. Pahipa have greater than 35 percent cobble in the control section.

DRAINAGE AND PERMEABILITY: Well drained. Runoff is medium. Permeability is moderately rapid in the soil.

USE AND VEGETATION: These soils are used for pasture, forest reserve and wildlife habitat. The natural vegetation is koa (Acacia koa), ohia lehua (Metrosideros polymorpha), hapuu (Cibotium spp.), olapa (Cheirodendron trigynum) and kopiko (Psychotria hawaiiensis).

DISTRIBUTION AND EXTENT: Soils of his series are moderately extensive; total extent is about 25,000. MLRA is 160.

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

SERIES ESTABLISHED: Soil Survey of Hawaii, 1949REMARKS: Diagnostic horizons and features recognized in this pedon include: Udic Moisture Regime
Isomesic Temperature Regime
Andic properties - 0 to 127 centimeters (0 to 50 inches)
Cambic horizon - 41 to 127 centimeters (16 to 50 inches)
Umbric epipedon - 0 to 41 centimeters (0 to 16 inches)
Paralithic materials - 69 to 127 centimeters (27 to 50 inches)
Degree of cementation of paralithic materials - weakly to strongly cemented

Edit Log:
5/11 MRK. Updated OSD to current standards and use; horizon designations changed, dry colors added, range of characteristics augmented, type location better defined.

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National Cooperative Soil Survey
U.S.A.