El Yunque National Forest, formerly known as the Luquillo National Forest, and the Caribbean National Forest, is a forest located in northeastern Puerto Rico. It is the only tropical rain forest in the United States. The forest is commonly known as El Yunque, which may be attributed to either a Spanish approximation of the aboriginal Taino word yu-ke which means "white lands", or the word anvil, which means yunque in Spanish. The second-tallest mountain within El Yunque is also named El Yunque. El Yunque National Rainforest is located on the slopes of the Sierra de Luquillo Mountains and it encompasses 28,000 acres (43.753 mi² or 113.32 km²) of land, making it the largest block of public land in Puerto Rico. El Toro, the highest mountain peak in the forest rises 1,065 meters (3,537 ft) above sea level. Ample rainfall (over 200 inches a year in some areas) creates a jungle-like setting - lush foliage, crags, waterfalls and rivers are a prevalent scene. The forest has a number of trails from where the jungle-like territory's flora and fauna can be appreciated.
The forest region was initially set aside in 1876 by the King Alfonso XII of Spain, and represents one of the oldest reserves in the Western Hemisphere. It was established as the Luquillo Forest Reserve on 17 January 1903 by the General Land Office with 65,950 acres (266.9 km2), and became a National Forest in 1906. It was renamed Caribbean National Forest on 4 June 1935. It is home to over 200 species of trees and plants, 23 of which are found nowhere else. The critically endangered Puerto Rican Amazon (Amazona vittata), with an estimated wild population of 30 individuals, occurred exclusively in this forest until 19 November 2006, when another wild population was released by the Department of Natural Resources in the municipality of Utuado's Rio Abajo State Forest.
An Executive Order signed by President George W. Bush on 2 April 2007 changed the name of the Caribbean National Forest to El Yunque National Forest, better reflecting the cultural and historical feelings of the Puerto Rican people. Because Puerto Rico is south of the Tropic of Cancer, it has a tropical climate. There is no distinct wet or dry season in the El Yunque; it rains year round. The temperature and length of daylight remain fairly constant throughout the year. All of these factors provide a year-round growing season.
Its ecosystem is specifically surveyed by the Management Team of Ecosystems, (Equipo de Manejos de Ecosistemas) which is led by Pedro Rios. Due to its location in the North Eastern part of Puerto Rico the incoming trade winds from the Atlantic Ocean bash into the mountains, leading to an excess of rainfall registered at about 6m (240 inches) per year "About the Forest". This process is called the orographic lift and accounts for the intense rainfall and constant cloud presence in this mountainous region. This constant cloud cover and persistent winds produced by the adiabatic process of air particles rushing up through the mountainside has affected the morphology of El Yunque, but the most effect has been on the Bosque Enano or the Dwarf Forest