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Historically, oak savanna was the predominant habitat on the upland areas now part of Sherburne National Wildlife Refuge. This plant community is characterized by scattered individuals and clumps of oaks growing with an understory dominated by tall grasses and colorful prairie flowers. Oak savanna was historically a very dynamic habitat, fluctuating into a more open or less open state depending on frequency of wildfires or drought. It was associated with the more open prairie areas and also more dense oak woodlands and brushlands. On the Refuge today, woodland areas and prairie openings are considered a part of the oak savanna.
The Refuge is reestablishing prairie grasses and wildflowers that once dominated the oak savanna through an active planting program. Seeds are purchased or harvested from local seed sources for this use. Big bluestem, little bluestem, Indian grass and switch grass, as well as a rich diversity of native prairie wildflowers (forbs) can now be found here. The sandy soils on the Refuge provide well-drained growing conditions for many plants more typically found in more arid regions of the west. Several species of wildflowers, such as lupine, hoary puccoon, and Indian paintbrush, are found in the Refuge at the limits of their range. Oak seedlings are being planted in some portions of the Refuge to restore the overstory of the oak savanna while in other areas oaks are naturally spreading into the grassland plantings.
Oak savanna is a fire dependent plant community. At Sherburne Refuge this plant community is restored and maintained by prescribed burning. Burning serves three primary functions. It encourages the growth of native wildflowers and warm season grasses, such as big and little bluestem, Indian grass and switch grass, which provide food and cover for nesting waterfowl and wildlife. It also reduces competition from exotic cool season grasses and encroaching trees and shrubs that are not fire tolerant. In addition, prescribed burning opens up the canopy in more heavily wooded areas, to re-create oak savanna.
Through prescribed burning, oak savanna is once more becoming the dominant habitat on upland areas of the Refuge. With the re-establishment of the vegetation which historically existed on the Refuge, the animals of the oak savanna are also returning.
