The Orosí Sector is 6,150 hectares of intermediate elevation transitional dry-moist forest and lower elevation rainforest (500-1000 m) located on the western slope of Orosí Volcano, a volcano that had its last eruption some 10,000 years ago and belongs to the Orosí-Cacao volcano complex which is estimated to be 500,000 years old.
The Maritza Biological Station is located here at 650 m some few hundred meters from the continental divide where the Tempisque River which empties into the Pacific Ocean and the Sapoá River which runs into Lake Nicaragua and eventually the Caribbean Sea are born. This area also has many creeks and streams making it an ideal site to study aquatic biology.
This sector has great archeological importance with its many hundreds of petroglyphs dating to more than 1500 years old dispersed over a large area especially around the Pedregal Site.
Sectors Program Management
The installations at the Maritza Biological Station include dormitories for 32 visitors, a research lab, a classroom, a multi-use room, housing for the resident biologist and for Sectors Program staff who are responsible for the maintenance of the station and internal trails and roads as well as conducting patrols on horseback over the entire sector to control illegal hunting and detect forest fires in the dry season. Sectors Program staff also provide support to researchers, groups, and students in their research, photography, archeology and other pursuits.
History
Until 1985 the Orosí Sector, though protected as the Orosí Forest Reserve where logging was illegal and through the 1917, 1955 law establishing land 2km around the craters of Costa Rica's volcanoes as national park, included a 30 km2 cattle ranch owned by the american Cecil Hylton and managed by Gustavo Echeverri of the Ranchos Horizontes company and was gradually deforested despite the laws protecting it. By 1985, the cattle ranch activity had decreased greatly and Mr. Hylton decided to donate the property to The Nature Conservancy as part of the Guanacaste National Park at which time the cattle were moved out and patrols began in 1986 to control illegal hunting.
