Kisatchie National Forest, the only National forest in Louisiana, USA, is located in the forested piney hills and hardwood bottoms of seven central and northern parishes. It is part of the Tertiary uplands (some of Louisiana's oldest rocks) and has large areas of longleaf pine forests (a forest type that has declined significantly over the last century). It is one of the largest pieces of natural landscape in Louisiana, with some 604,000 acres (2,440 km sq) of public land, more than half of which is vital flatwoods vegetation, which supports many rare plant and animal species. There are also rare habitats such as hillside seepage bogs and calcareous prairies. The forest also contains and provides a buffer for the Kisatchie Hills Wilderness, a nationally designated wilderness area that contributes to protecting biodiversity of the coastal plain region of the United States.