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. At 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.