19. Oak Savanna

  •  The Oak Savanna is a transition zone between the big woods to the east and prairies to the west.  Fire would rip across the prairie and into a wooded area. Oak SavannaAt this interface, scattered groves of bur oaks became the dominant vegetation because their corky bark gives them the ability to withstand fire. 
  • As a result of limited competition for sun, the oaks were majestic with wide canopies and wide low branches. Under the dappled shade of these trees, a special combination of prairie and forest groundlayer plants and animals coexist.
  • Less then 0.01% of Oak Savanna is left in Minnesota due to settling and lack of fire.
  • The Oak Savanna at Saint John's Abbey Arboretum was used for grazing cattle, which kept invading tree growth minimal, but damaged the ground layer vegetation. 
  • The ground layer vegetation has been planted to native prairie grasses and forbs.

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