In 1991, North American Douglas Tompkins, a long time visitor to Chile since 1961, bought the Reñihué Ranch with the idea to set aside 42,000 acres of evergreen temperate rain forest from possible exploitation. In the intervening years The Conservation Land Trust has added another 700,000 acres in nearly contiguous parcels to comprise the Pumalín Park. These properties have been declared a Nature Sanctuary on August 19, 2005, a special designation of the Chilean State, granting it additional environmental and non developmental protection. The Conservation Land Trust (a U.S. environmental foundation) has donated these protected lands to Fundación Pumalín (a Chilean foundation), for their administration and continual development as a type of National Park with public access under a private initiative.

Chile's basic environmental law has incentives for such private initiatives, although The Conservation Land Trust has not received any financial support from the Chilean government. Being a new form of private environmental philanthropy in Chile, the project has met with political opposition, primarily from those who do not understand how such an initiative would work. Slowly but surely, confidence has been built, both locally and nationally, and the project continues to move along, giving access to the public as originally envisioned. Visitor facilities similar to those found in National Parks throughout the world such as hiking trails, campgrounds, information centers, cafés, cabanas, boat excursions and the like are being developed under strict conservation guidelines. Already thousands of visitors are enjoying these facilities.

The project has developed consistently over the years, and includes the development of a park ranger system, utilizing non-uniformed park rangers on the agricultural lands adjacent to the Nature Sanctuary. Small farms with productive activities such as animal husbandry, cheese making, eco-tourism, wool handicrafts and organic gardens are simultaneously park stations and visitor information centers. In this way both conservation and a productive contribution to the local economy are achieved. The project is aware of the need to include neighbors of the park, to create a shared feeling for the need to protect wildlands and biodiversity, often a consciousness that is lacking due to the cultural and historical conditions. This effort is seen as long term, slow, and difficult, but is critical if any form of "sustainable" living or economy is to be achieved.

A secondary objective is to provide a place for Chileans and international visitors to experience pristine nature, to develop a heightened awareness of the magic and beauty of the natural world, and in turn become active in their daily lives to value and protect nature.

Finally, it is hoped that this project will act as a model for other private conservation initiatives, not just at this scale but at any level. Wildlands philanthropy has been responsible for thousands of projects all over the world, protecting wetlands, animal and plant life, habitats, forests, prairies, deserts, and so forth. It is said that in North America there is not one National Park that has not had some measure of private philanthropy involved in its development. In Chile as well, Torres del Paine, Cañi Sanctuary, Alto Huemul, Yendegaia and, of course, Pumalín are all recent examples of private donors benefiting the public welfare.