5.10. SR 12-20-2004 - Laserfiche WebLink

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Landforms also have a profound impact on the type of plant communities found in any area. As was mentioned previously. the landforms of the area are primarily glacial in origin. Direct glacial modification of the landscape, such as the deposition of till, and moraine, and the influence of periglacial processes such as outwash, have formed the vast majority of the landforms in this region. Most of the deposited materials associated directly with glaciers, such as till and moraine are unsorted. These consist of materials, which range in size from clay and fine sand to large boulders in a random arrangement. Overall, the materials deposited in the City tend to form well-drained to very well-drained landscapes with sands and gravels common. In addition to the influences of climate and landform, landscape position also has a profound impact on the type of plant communities supported. Angle, position, and aspect of slope all strongly influence plant species that can be supported in an area. Slope aspect plays a significant role since it tan exaggerate the influence of the sun and the amount of water plants loose through their leaves on south- and southwest- fating slopes making these areas more hospitable to prairie or dry oak communities. North-facing slopes tend to be moister and have a tendency to be occupied by woodlands/forests. Historic InfJuence of Humans on the Landscape Ideas about the history of Native Americans and their influence on the local landscape are still evolving. Native Americans have probably inhabited and hunted in the area for over 10,000 years. While their impacts were not as great as those of European settlers, Native Americans used a wide variety of plants and animals for food, and . altered vegetation patterns for cultivation and by setting fire to broad expanses of landscape. Native Americans (and European fur traders) used fire to hunt game; create desired habitat; clear the landscape for travel, communication and defense; and obtain firewood. While some fires in the region would have occurred naturally, the activities of Native Americans undoubtedly accounted for the vast majority of fires. Prairies, savannas, and oak forests are fire-dependent plant communities, and would most likely not have been present in the Twin Cities Area at the time of European settlement without these fires. At the time of settlement, around 1850, the landscape of the study area supported a rich variety of plant communities including various types of wetlands in low areas and oak and aspen woodlands, brushlands and prairies on drier uplands. As the City City of Elk River, MN - Natural Resouce Inventory Bonestroo Natural Resources, September 2004 5