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<br />• Soils Information: <br />Topsoil textures vary from loams to gravelly loams and fine s.3ndy loams. <br />Topsoil depth also is highly variable (8" to 60") and in gene.^al is well <br />suited for the establishment and growth of native and/or intr~~duced grasses, <br />shrubs, and trees. See the attached mapping unit descriptions for additional <br />soils information. <br />Vegetation Information: <br />The present vegetation is a cottonwood-shrub association. The cottonwoods <br />represent essentially a mature stand and are from forty to sixty feet in <br />height. The cottonwoods are present on approximately eighty f~ercent of <br />the site. Overstory canopy cover varies from one to fifty pec•cent on the <br />areas where the cottonwoods occur. Tall shrubs (four to ten feet) make up <br />twenty to thirty percent of the understory canopy in widely scattered <br />areas while forbs and low shrubs may make up ninety percent of the under- <br />story foliage in other areas. Due to overgrazing, grasses occur in the <br />understory only in traces and up to twenty percent. Russian k.napweed <br />has invaded much of the area and occurs in thick stands. <br />Tall shrubs found on the site are skunk bush sumac Rhus Trilotata, basin <br />big sagebrush Artemesia tridentata tridentata, blackbrush Coleogyne <br />ramosissima, tamarisk Tamarix pentandra, and willow Salix spp. Occasional <br />• clumps of Russian-olive, Elaeagnus angustifolia, are found, which have <br />both immature and mature stages of growth present. The sumac, sagebrush, <br />and blackbrush are found in association with each other on drier, better <br />drained areas. The willow occurs in pure stands on areas with poor drainage. <br />Rabbitbrush, Chrysothamnus viscidiflorus, grows as a low shrub in the <br />forb/grass understory, but is not present in significant amounts. Russian <br />Knapweed Centurea repens and kochia Kochia scoparia are the primary under- <br />story forbs. <br />Grasses present are inland saltgrass Distichlis stricta, squirreltail <br />Sitanion hystrix, sanddropseed Sporabolus cryptandrus, and a three awn <br />Aristida spp. Saltgrass is the dominant grass. <br />Reclamation Considerations: <br />Understory annual production on more mesic riverbottom sites may be as <br />high as 4000 pounds per acre air dry forage but on this site would likely <br />not exceed 1000 pounds if in excellent condition. Trees and snrubs undis- <br />turbed by gravel extraction should be left for wildlife cover .and food <br />as well as for ecological diversity. <br />• <br />