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<br />and oak forest were probably present as well, especially beneath tree or shrub <br />canopies. <br /> <br />Mesic oak savanna is rare throughout Minnesota. Historically, it occurred in the prairie <br />and deciduous forest-woodland zones. Mesic oak savanna occurred on dry-mesic to <br />mesic, gently undulating to moderately sloping sites. These sites were on glacial till or <br />outwash, with soil texture ranging from clay loam to sandy loam. Mesic Oak Savanna <br />generally occurred on sites where fire was frequent enough to prevent trees and <br />shrubs from forming closed canopies, thereby permitting heliophilous sun-loving prairie <br />herbs to dominate the ground layer. However, fire frequencies were lower than in <br />prairies on similar topography and soils. <br /> <br />Native grazing and browsing animals may also have helped maintain the open <br />character of mesic oak savanna. Within the deciduous forest-woodland zone, where <br />landscape character reduced fire frequency on a large scale, mesic oak savanna often <br />covered larger areas. With settlement and the suppression of prairie fires, savannas <br />in the deciduous forest-woodland zone that escaped clearing and cultivation quickly <br />succeeded to woodland unless heavily and continuously grazed. No high quality <br />examples are known to remain in Minnesota. <br /> <br />Dry Oak Savanna - (MLCCS Codes 62120, 62122/62 Total Acres) <br />A total of nine dry oak savanna polygons were documented in the city. Three <br />occurrences were dry oak savanna-barrens subtype and six dry oak savanna-subtype <br />unspecified. Dry Oak Savanna occurs on the same kinds of landforms as Dry Prairie, <br />except for bedrock bluffs. The <br />barrens subtype of dry savanna <br />occurs on the same kinds of sand <br />deposits as the Barrens Subtype of <br />Dry Prairie. On dune blankets~ it <br />tends to be favored over prairie in <br />areas of sharper relief. Bur oaks <br />are generally the prevalent trees, <br />but northern pin oaks are also <br />common. <br /> <br />Small, gnarly, open-grown trees are <br /> <br />most common, although in moister <br /> <br />City of Elk River, MN - Natural Resouce Inver <br />Bonestroo Natural Resources, September 2004 <br /> <br /> <br />Dry oak savanna/barrens prairie in Section 18, Elk River <br />