SBCT Final EIS - Govsupport.us

Chapter 3 ⎯ Affected EnvironmentForest cover at DTA is diverse and includes pure stands of spruce, hardwoods, and spruce/hardwoodmixtures. The dominant types include white spruce (Picea glauca), paper birch (Betula papyrifera),quaking aspen (Populus tremuloides), balsam poplar (Populus balsamifera), black spruce (Piceamariana), and spruce/hardwood.Scrub communities occur at high mountain elevations, in small stream-valley bottoms, and as “pioneer”vegetation on disturbed sites. Typical scrub fields are composed of alder, willow, and dwarfbirch (Betula nana). Krummholz spruce stands are relatively common at higher elevations. Densethickets of scrub communities, dominated by willow and alder, exist along floodplains or disturbedsites such as gravel pits, road shoulders, ROWs, and military trails (USARAK 1980).Most barren areas on DTA are located on gravel bars along the Delta River, the Little Delta RiverDelta Creek, Jarvis Creek, and Granite Creek (Jorgensen et al. 2001). Barren lands also occur abovetree line, along ridges, and adjacent to rivers and streams. Barren sites are also located near the smallportion of Trident Glacier that lies within DTA.Higher elevation sites along the southern portion of DTA support moist tundra, which grades into alpinetundra, and then into barren land. These areas occur on MacArthur Mountain, Patton Mountain,Molybdenum Ridge, and Trident Glacier (USARAK 1980; Jorgenson et al. 2001). Small areas oftundra also exist in the northwest portion of DTA at elevations above 3,500 to 4,000 feet.Many potential timber stands at DTA are not harvestable because they are located in impact areascontaminated by unexploded ordnance. Current commercial potential for the remainder is limited tofirewood, sawtimber, and half-log white spruce markets.WetlandsApproximately 68 percent (431,940 acres) of DTA is wetland (Lichvar 2000), with palustrine, riverine,and lacustrine types included. The palustrine shrub wetlands are the most common types at DTA.According to Lichvar 2000, the most prevalent ecotypes likely to be wetlands at DTA include:• Lowland Wet Low Scrub and Lowland Tussock Scrub Bog (35 percent of DTA) – These palustrinewetlands are characterized by loamy soils that are poorly drained because of permafrost. Thebogs contain sedges, tussock meadows, and lowland moist meadows with bluejoint reedgrass.Willows, dwarf birches, and forbs may also be present.• Lowland Wet Needleleaf Forests (12 percent of DTA) – Soils are loamy, poorly drained becauseof permafrost, and moderately acidic. These forests are dominated by black spruce. This type ofwetland is common in the Donnelly Drop Zone and Eddy Drop Zone.• Alpine Wet Tussock Meadow and Alpine Wet Low Scrub (6 percent of DTA) – These ecotypesare characterized by loamy soils, underlain by permafrost, and are moderately to strongly acidic.These areas are found above tree line, primarily in the southern portion of DTA West, along thefoothills of the Alaska Range.• Riverine Wetland Complex (6 percent of DTA) – These areas are located along inactive floodplainsof meandering and headwater streams with soils consisting of inter-bedded silts and sands.Wetlands located along the Delta River and Jarvis Creek are riverine.• Lacustrine Wetland Complex (1 percent of DTA) – Lacustrine water bodies are ponds and lakeswith or without emergent or floating vegetation, and wetland vegetation on the margins. This alsoincludes basins in fine-grained lacustrine deposits with vegetation dominated by grasses.February 2008 3–127 2/25th SBCT Final EIS