Browsing by Author "Cushing, Edward J."

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    Establishment of Native Sedge Vegetation in Created Wetlands
    (Minnesota Department of Transportation, 1999-02) Budelsky, Rachel A.; Cushing, Edward J.; Galatowitsch, Susan M.
    This report presents the results of a four-year study on techniques for revegetation of native sedges in created basins. Although often the dominant genus in shallow wetlands, sedges (Carex spp.) do not readily recolonize after restoration or creation of the water table. It is unlikely that sedges will naturally establish in created wetlands. The results of seed germination studies on five Carex species suggest the highest germination rates in fresh seeds - with one exception. Wet/cold storage also can prolong seed viability for at least two-and-a-half years. Dry storage is not recommended for wetland sedge seeds. Short-term wet/cold treatment after prolonged dry storage does not improve germination rates. Sensitive to deep water, rising water levels, and competition during the establishment year, seedlings grew well across a wide range of water depths in subsequent growing seasons. Both species outcompeted annual weeds within two to three growing seasons, but not Phalaris arundinacea (reed canary grass). The study recommends weed control during the establishment year to prevent the invasion of P. arundinacea. Wetland soil promotes seedling growth relative to other soils, but does not affect germination rates. Because of the potential for the introduction of undesirable weeds, the study does not recommend the use of donor wetland soil. Instead, study results suggest the potential for the use of organic top-dressings.
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    Late-Wisconsin Pollen Stratigraphy in East-Central Minnesota
    (1963) Cushing, Edward J.
    Reconstruction of the landscape bared by the melting Grantsburg sublobe is aided by pollen diagrams from three sites. At Horseshoe Lake and Cedar Bog Lake, on the Anoka Sand Plain, the pollen spectra above a thin basal layer of plant detritus are dominated by Picea, but other conifers (except Pinus), deciduous trees (especially Populus, Fraxinus, Betula, and Quercus), and herbs (chiefly Cyperaceae, Artemisia, and Ambrosia-type) are well represented. Comparison of the pollen flora of this late-Wisconsin zone with modern floristic provinces emphasizes its complexity. Although plants now common to the Boreal and Great Lakes provinces contributed about one-half of the pollen rain, 35 of the 104 taxa identified belong to deciduous elements, and a prairie element is represented by 6 taxa. Secondary redeposition of part of the late-Wisconsin pollen flora cannot explain its singularity. At Andree Bog, on the Lake Grantsburg plain, the basal spectra are contaminated by secondary microfossils largely Cretaceous in age, and their subtraction has little effect on the pollen flora. At Horseshoe Lake and Cedar Bog Lake the amount of secondary pollen is negligible. The available radiocarbon dates indicate that some lakes on the Anoka Sand Plain were open as early as 12,500 radiocarbon years ago but that melting of buried ice may have continued for as long as 1000 years. On this unstable surface a mosaic of forest and openings is visualized, with Picea, Fraxinus, Populus, and other deciduous trees on moist sites and prairie species in more xeric habitats.