2002-07-08_GENERAL DOCUMENTS - M2002004 (4)

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however, that the increase in total shrub density was favorable in helping to meet the shrub density regulatory standard for reclamation bond release. An important finding from the Schuman and Booth study is big sagebrush seed apparently maintains its viability for a much longer time than previously thought. New seedlings were noted three and five years after the initial seeding. The study Grass Competition and Sagebrush Seeding Rates: Influence on Sagebrush Seedling Establishment (Fortier et al. 1999) is in its first year and only preliminary results are reported. First growing season data for big sagebrush seedling performance under three sagebrush seeding rates and seven grass seeding rates were mixed. Heavy spring and early summer precipitation masked the expected effects of increasing grass competition. However, big sagebrush seedling density did show a direct relationship with seeding rates, and big sagebrush seedling density was lower at the higher grass seeding rates. Big sagebrush seedling density declined with decreasing precipitation and soil moisture content through the summer for all seeding rates, and the greatest seedling loss was seen in the highest big sagebrush seeding rates. All three big sagebrush seeding rates of 1 kg/ha, 2 kg/ha, and 4 kg/ha met the regulatory required density of 1 shrub per square meter at the end of the first growing season. SUMMARY The research conducted under the Wyoming ACMLRP has shown that the establishment of natural big sagebrush stands is episodic and appears to be dependent upon winter and early spring precipitation patterns immediately following seedling establishment. Other findings of significance are: 1. Big sagebrush seedlings are sensitive and susceptible to winter desiccation. 2. Big sagebrush seedlings are sensitive to late growing season moisture stress. 3. Big sagebrush seedlings are intolerant of grass and/or herbaceous competition, apparently for the above stated reasons. 4. Direct placed topsoil is not an apparent source of big sagebrush seed or propagules. 5. Myconhizae are important in helping big sagebrush seedlings to survive periods of moisture stress. 6. Direct placed topsoil generally has higher soil moisture content and mycorrhizal spore counts, both of which are beneficial to big sagebrush seedling establishment and survival, than does stockpiled topsoil. 7. Big sagebrush should be seeded a season or two before grass or herbaceous species to insure seedling establishment. 8. Stubble mulch or straw mulch provides protection to big sagebrush seedlings from winter desiccation and to maintain soil moisture contents for longer periods of time. 9. Big sagebrush seed has an apparent longer viability than previously thought, up to three to five years.