LOCATION TRAPPER MTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive Eutric Haplocryalfs
TYPICAL PEDON: Trapper stony loam - native cover. (Colors are for dry soil unless otherwise noted.)
01 & l-O"--Leaves and twigs of conifers and very dark gray (lOYR 3/1) organic mat, black (lOYR 02 2/1) moist; many very fine and medium roots; neutral (pH 7.0).
A2 0-6"--Light gray (lOYR 7/2) stony loam, grayish brown (lOYR 5/2) moist; weak fine crumb structure; soft, very friable, slightly sticky, nonplastic; many very fine, fine and medium roots and tubular pores; neutral (pH 6.7); gradual boundary. (4 to 8 inches thick)
A3 6-8"--Pale brown (lOYR 6/3) stony heavy loam, brown (7.5YR 5/4) moist; moderate medium blocky structure; slightly hard, friable, slightly sticky, slightly plastic; many fine and medium roots and tubular pores; clear wavy boundary. (1 to 3 inches thick)
B21t 8-16"--Yellowish brown (lOYR 5/6) stony clay loam, strong brown (7.5YR 4/6) moist; moderate medium blocky structure; slightly hard, friable, slightly sticky, slightly plastic; many fine and medium roots and tubular pores; dark brown (lOYR 3/3) organically stained clay coats on some surfaces of peds; neutral (pH 7.0); gradual boundary. (6 to 10 inches thick)
B22t 16-23"--Brownish yellow (lOYR 6/6) stony light clay loam, yellowish brown (lOYR 5/6) moist; moderate medium blocky structure; slightly hard, friable, slightly sticky, slightly plastic; common fine and medium roots and tubular pores; few dark brown (lOYR 4/3) organically stained clay coats on some faces of peds; mildly alkaline (pH 7 6); clear boundary. (6 to 8 inches thick)
B3 23-27"--Very pale brown (lOYR 7/4) stony loam, light yellowish brown (lOYR 6/5) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; few roots; calcareous but without segregated lime; moderately alkaline (pH 8.0); abrupt wavy boundary. (2 to 5 inches thick)
Cca 27-46"--White (lOYR 8/2) stony loam, very pale brown (lOYR 7/3) moist; massive; soft, friable, nonsticky, nonplastic; few large roots and channels filled with decaying roots; one inch thick peat-like mat of decayed roots at base of horizon; very strongly calcareous with much flower-like accumulated lime; very strongly alkaline (pH 9.0); abrupt wavy boundary. (12 to 30 inches thick)
R 46-60"--Marble-like limestone with vertical crevices filled with very pale brown (lOYR 8/4) loam, yellow (lOYR 8/5) moist; soft, very friable, nonsticky, nonplastic.
Type Location: Ravalli County, Montana; on Sapphire Mountain range east of Hamilton, Montana in NW part of sec. 15, T.7N., R.l9W.
Range in Characteristics: Depth to limestone ranges from 40 to 80 inches. m e noncalcareous part of the solum is 12 to 30 inches thick. Volume of stone fragments ranges from 10 to 30 percent. Mean annual soil temperature ranges from 44 to 47 degrees F. Average summer soil temperature ranges from 42 to 47 degrees F. on north and east exposures under an O horizon and full forest canopy. The hue is 2.5Y through 7.5YR. The A2 horizon has value of 7 or 6 dry and 6 through 4 moist and chroma of 2 through 4. It is slightly acid to neutral. The B2t horizon has value of 5 or 6 dry and 4 or 5 moist and chroma of 3 through 6. It contains 18 to 35 percent clay. This horizon slightly acid to mildly alkaline. The Cca horizon contains 20 to 40 percent CaC03 excluding coarse fragments.
Competing Series and their Differentiae: These are the Edloe, Gorus, Indart, Lick, Sapphire, Swapps, Swifton, Tahoma, Tongue River, Uinta, Whitefish and Woodrock series. Edloe, Sapphire, Tahoma, Tongue River, and Woodrock soils have noncalcareous solums. Gorus, Lick, Swifton and Uinta soils lack a Cca horizon. Indart soils have a paralithic contact at depths of 20 to 40 inches. Swapps soils lack A2 horizons, have 5YR hue in the B2t horizons and have limestone bedrock at depths ranging from 20 to 40 inches. Whitefish soils have strongly to medium acid A and A Ł B horizons.
Setting: The Trapper soils are on hilly and mountainous lands on pre-Cambrian dolomite limestone, chiefly of the Belt series of rocks. Some sandstone, quartzite and argillite rocks occur. The climate is cold, subhumid with 25 to 40 inche8 aveFage annual precipitation, 40 to 45 degrees F. mean annual temperature and 50 to 60 degrees F. average 8ummer temperatures.
Principal A8sociated Soils: These are the Duncom, Little Horn, Tropal and Whitore Łoil8. Duncom and Little Norn soils have mollic epipedons. Tropal and Whitore 80ils have ochric epipedon8 over calcic horizons.
DrainaŁe and Permeability: Well-drained; slow runoff; moderate permeability.
Use and Ve etation: Used for production of fore9t products, wildlife habitat, watershetŁ and 8ummer range for Łive8tock. Dominant plants are Douglas-fir, lodgepole pine, piaegraas and Oregon gŁape.
Distribution and Extent: Trapper soils occur throughout the Rocky Mountaing in weatern Montana. They are moderately exten8ive.
Series E8tablished: Ravalli County (Bitterroot Area), Montana, 1952.
Remarks: Trapper soils formerly were classified with a8 Grey Wooded 80ils.
OSED scanned by NSSQA. Last revised by state 9/71.