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Soil and ecological land unit survey <br />USE AND MANAGEMENT CONSIDERATIONS <br />Major uses: wildlife habitat and watershed. <br />Mass movement potential: <br />Landslides: low. <br />Debris flows: low. <br />Snow avalanche: low. <br />Sediment delivery efficiency. moderate. <br />Road and trail limitations: <br />Cut and fill slope stability <br />Leighcan: moderate- unconsolidated <br />substratum. <br />Howardsville: moderate- unconsolidated <br />substratum. <br />Improved unsurfaced roads: <br />Leighcan: severe- slope and erosion hazard. <br />Howardsville: severe- slope and erosion <br />hazard. <br />Offroad vehicle roads and trails: <br />Leighcan: severe- slope and erosion hazard. <br />Howardsville: severe- slope and erosion <br />hazard. <br />Foot trails and paths: <br />Leighcan: moderate- slope and erosion <br />hazard. <br />Howardsville: moderate- slope and erosion <br />hazard. <br />Revegetation limitations: <br />Leighcan: moderate- low available water <br />capacity, slope and erosion hazard. <br />Revegetation considerations: Mulch or similar <br />treatment will protect the soil from erosion, help <br />conserve, soil moisture and protect emerging <br />plant seedlings. <br />Timber management considerations: Trees to <br />plant include Engelmann spruce, subalpine fir, <br />and lodgepole pine. <br />Wildlife management considerations: This map <br />unit provides shelter and limited food during <br />summer through fall months. Thinning or <br />creating small openings in the overstory canopy <br />cover can stimulate understory productivity. <br />Other management considerations: <br />Management activities are limited by steep slopes <br />and erosion hazard. South facing slopes are <br />difficult to revegetate after a disturbance and as a <br />result have a higher potential for erosion. Some <br />areas of this map unit occur in generally remote <br />areas which have had relatively little disturbance <br />other than fire. These undisturbed areas can <br />contain old growth trees. <br />Acid precipitation buffering capacity: low. <br />Map Unit: 693G-Howardsville family, 15 to 25 <br />percent slopes. <br />Ecological Land Unit: 693G-subalpine fir and <br />Engelmann spruce on subalpine reworked <br />ground moraines. <br />MAP UNIT SETTINGS <br />Location: glaciated areas where igneous and <br />metamorphic rocks predominate. <br />Landform: reworked ground moraines. <br />Parent material., glacial till and alluvium. <br />Geologic symbol. Qd, Qa. <br />Elevation range: 9,000 to 11,600 feet. <br />Aspect: all. <br />Climatic zone: subalpine. <br />Mean annual precipitation: 20 to 40 inches. <br />Mean annual air temperature: 340F. to 400F. <br />Average annual snowfall. 200 to 400 inches. <br />COMPOSITION <br />95 percent Howardsville and similar soils. <br />Contrasting inclusions <br />5 percent Cryaquolls, Cryaquents, and organic <br />soils near streams. <br />TYPICAL PROFILES: <br />Howardsville <br />Surface covering layer: <br />1 to 0 inches - conifer litter. <br />Surface layer(s): <br />0 to 2 inches - pale brown, very stony sandy <br />loam. <br />Subsurface layer(s): <br />2 to 13 inches - very pale brown, very stony <br />loamy sand. <br />Subsoil layer(s): <br />13 to 24 inches - light yellowish brown, <br />extremely stony loamy sand. <br />Substratum layer(s): <br />24 to 60 inches - brownish yellow, extremely <br />stony loamy sand. <br />SOIL PROPERTIES AND QUALITIES <br />Howardsville <br />Effective rooting depth: greater than 60 inches. <br />Drainage class: excessively. <br />Depth to seasonal high water table: greater <br />than 6 feet. <br />Available water capacity: very low. <br />Permeability. rapid. <br />Runoff.• slow. <br />VEGETATION <br />Potential natural communities: <br />Howardsville: lodgepole pine/Rocky Mountain <br />whortleberry (PicoNamy) below 10,000 feet and <br />subalpine fir-Engelmann spruce/Rocky <br />Mountain whortleberry (Abla-PienlNamy) <br />Page 94 DRAFT 3/2112011