Prior to urban development of the South Florida region, pine rocklands covered approximately 161,660 acres (654.2 km2) in Miami-Dade County. Within Everglades National Park, 19,840 acres (80.3 km2) of pine forests are protected, but outside the park, 1,780 acres (7.2 km2) of pine communities remained as of 1990, averaging 12.1 acres (49,000 m2) in area.[61] The misunderstanding of the role of fire also played a part in the disappearance of pine forests in the area, as natural fires were put out and pine rocklands transitioned into hardwood hammocks. Prescribed fires occur in Everglades National Park in pine rocklands every three to seven years.[65]