El Yunque National Forest is a forest reserve located in northeastern Puerto Rico, is located on the slopes of the Sierra de Luquillo mountains. and is the only tropical rain forest in the U.S. National Forest System. High annual rainfall creates a jungle-like setting with lush foliage, crags, waterfalls and rivers.
El Yunque National Forest (Bosque Nacional El Yunque), formerly known as the Caribbean National Forest, is a forest reserve located in northeastern Puerto Rico. It is the only tropical rain forest in the United States National Forest System.
This forest is commonly known simply as "El Yunque," which may be attributed to either a Spanish approximation of the aboriginal Taíno word yu-ke which means "white lands," or the word "anvil," which is yunque in Spanish. High annual rainfall (over 20 ft a year in some areas) creates a jungle-like setting with lush foliage, crags, waterfalls, and rivers. The second-tallest mountain within El Yunque is also named El Yunque.
El Yunque National Forest is located on the slopes of the Sierra de Luquillo mountains, encompassing 28,000 acres (43.753 sq mi or 113.32 sq km) of land, making it the largest block of public land in Puerto Rico. The highest mountain peak in the forest rises 3,494 ft (1,065 m) above sea level The forest has a number of trails from which the jungle-like territory's flora and fauna can be appreciated. El Yunque is also renowned for its unique Taíno petroglyphs.
Because Puerto Rico is south of the Tropic of Cancer, it has a tropical climate. There is no distinct wet or dry season in El Yunque; it rains year round. The temperature and length of daylight remain fairly constant throughout the year. The average temperature in the summer is 80 °F(26 °C) high and 68 °F (20 °C) low and in the winter 72 °F(22 °C) high and 58 °F(15 °C) low, Temperatures can Drop below 50 °F(10 °C) on clear nights during the Winter, but never below freezing. All of these factors provide a year-round growing season.
The rain forest ecosystem is exposed to 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. El Yunque is composed of four different forest vegetation areas: Tabonuco Forest, Palo Colorado Forest, Sierra Palm Forest, and Dwarf Forest.
The Dwarf forest ecosystem is located at around 3,000 ft (910 m) and composes the smallest sub-region in El Yunque. The forest is characterized by the variation of vegetation that is only found in Puerto Rico. The vegetation shows stunted growth in which the diameter of the trunk is widened and the number of leaves on the branches is lower than expected. Other specific factors that affect the growth of this sub-region are the high level of acidity and poor water runoff from the soil.
Although many species have adapted to these harsh environments, five species are frequent in the dwarf forest: Ocotea spathulata Tabebuia rigida, Calyptranthes krugii, Eugenia borinquensis and Calycogonium squamulosum. The other abundant type of plants in the dwarf forest are epiphytes.
El Yunque supports a vast array of animal and plant life that varies depending on the altitude range in the rainforest. The great amount of competition in the canopy does not allow lower level plants to develop and prosper.
The characteristic of having a widened tree trunk is ideal for epiphytes that require a host to live. Therefore, a substantial amount of epiphytic plants have cemented their existence in the flora of El Yunque, specifically in the dwarf forest due to the moisture, precipitation and protection from the sun.
Although the El Yunque National Forest is one of the smallest forests in the U.S. National Forest System, (28,000 acres or roughly 11,300 ha), it is one of the most biologically diverse areas that the agency manages. El Yunque National Forest contains over 240 species of native trees, of which 88 are rare and 23 are only found in the forest. Along with the trees, the El Yunque National Forest includes 50 species of native orchids and over 150 species of ferns. This relatively small land area also supports 127 species of terrestrial vertebrate (land animals with backbones) and 10 species of aquatic invertebrates (water animals without backbones).
The El Yunque National Forest is the habitat of a total of 5 endangered species, (meaning they can die out in a short time), and 1 threatened species, (meaning it has the potential of dying out over a long lapse of time).
The Puerto Rican Parrot (Amazona vittata) is one of the ten rarest birds in the world and is only found on the Island of Puerto Rico. It is a small parrot that measures 11.0-11.8 in (28-30 cm). Its coloring is predominantly green with a red forehead and white rings around the eyes. The species is the only remaining native parrot in Puerto Rico.The island parrot population was estimated to number in the hundreds of thousands when first encountered during Columbus' second voyage of discovery. It dropped to a low of 13 birds in 1975. After this date the population reached an estimated 47 birds in the wild, declining again to 23 birds after Hurricane Hugo in 1989. Currently the wild flock is climbing but challenges are many and its future still hangs in the balance. There are a total of 79 adult birds in captivity in the aviaries of the El Yunque National Forest and Rio Abajo State Reserve. The remaining parrots and their nesting habitat are constantly monitored and managed through a cooperative effort between the Forest Service, the U.S. Fish and Wildlife Service, and the Puerto Rican Department of Natural Resources.
The Puerto Rican Boa (Epicrates inornatus) is found throughout the island, and lives in El Yunque below an elevation of 1200 feet (365 meters). Although the recovery plan for the boa was approved in 1986, its ecology is only now being understood through research conducted by the USDA Forest Service International Institute of Tropical Forestry.
The Puerto Rican Broad-winged Hawk (Buteo platypterus brunnescens) is a subspecies of the broad-winged hawk and is found in isolated mountain areas preferring to hunt from lofty perches. This hawk’s prey consists of frogs, lizards, other birds and insects. As of 1992 its population on the island was estimated at approximately 124 individuals. The cause of its decline has been due to forest destruction and habitat loss due to construction.
The Puerto Rican Sharp-shinned Hawk Accipiter striatus venator) — another subspecies of the sharp-shinned hawk — is a small forest hawk. Currently it is restricted to five isolated mountain-forest areas. Primarily it feeds on small birds. If you are fortunate you may see one streak by in the forest. Nest failures, deforestation, and habitat loss due to construction have played a significant role in the decline of this species.
Approximately 16 species of common coqui, members of the diverse neotropical frog genus Eleutherodactylus, are known in Puerto Rico. Of these 16, 13 have been found in El Yunque National Forest. This small frog earned its Puerto Rican common name due to the call of the most common coquí species in Puerto Rico, Eleutherodactylus coqui, which begins as the sun sets and ends in early dawn. This has made it an animal of great endearment to Puerto Ricans.
Although the coquí is an amphibian, it possesses some features that are unusual in frogs. These differences are seen mainly in its morphology, reproduction, and developmental stages. In terms of morphology, the coquí does not have webbing between its toes because it is a tree dweller in moist environments. Another significant difference is that it does not have a definite larval stage and the eggs laid by the female are terrestrial instead of aquatic. This means that a miniature frog-let, rather than a tadpole, arises from the incubation period.
Neotropical migrant birds breed in North America and migrate to the south for the winter. Approximately 35 species of these migratory birds either winter or pass through El Yunque during this season. They contribute significantly to the total animal diversity of the forest. The recent decline in the population of migratory birds throughout North America, Mexico, Central America, and the Caribbean is of growing concern. Major causes of declines in the populations of many of these species are believed to stem from the fragmentation of North American breeding habitat; also the loss of wintering habitats in Mexico, Central and South America, and the Caribbean.
Rivers and streams provide aquatic habitats for organisms that are important elements of the forest’s biological diversity. Most perennial (flowing year-round) and many ephemeral (flowing in short periods, yearly) streams on the forest support many aquatic species, including: seven species of fish, nine species of freshwater shrimp, and one species of freshwater crab. For ecological as well as recreational reasons, the forest’s aquatic resource values are very significant.
Within the forest boundary exists some of the most pristine and productive aquatic habitats remaining on the island. These nonrenewable resources are illegally fished with traps and spears. Harvest of these species are as yet unregulated, both on and off the forest. Monitoring surveys to determine their distribution, habitat needs, population status and trend are conducted regularly to protect these aquatic members of the forest’s family.