The city government of San Francisco mandated the development of management plans for all the "natural areas" under the city's control, and this process culminated in release of the "Significant Natural Resources Areas Management Plan" in February 2006. The plan favors the re-establishment of native species and species diversity in the city's parks. Some aspects of the plan have been controversial. For example, the plan envisions the removal of some large, mature trees (often eucalyptus, which was imported from Australia) to favor smaller native plants. The plan also includes new restrictions on recreational use of the park, such as the closure of some trails and of some areas for rock climbing, and prohibitions against unleashed dogs.