This document discusses the classification of public lands and natural resources according to the 1987 Philippine Constitution. It states that all lands, waters, forests, minerals and other natural resources belong to the State. Agricultural lands are the only alienable public lands; all other lands such as forest, mineral lands and national parks are inalienable. The Constitution classifies public lands into four categories: agricultural, forest or timber, mineral lands, and national parks. Private entities can only lease alienable public lands for a maximum of 25 years.