Enterolobium cyclocarpum, known in Costa Rica as guanacaste, caro caro or elephant-ear tree, is a member of the Fabacea family of plants, and is native to the American tropics, from central Mexico to the north of Brazil and Venezuela. It is know for its great size, its wide canopy, and its unusually shaped pods. The abundance of this species in Costa Rica, particularly in the Guanacaste region, to which it lend its name and where it is valued for its magnificent shade during the hottest days of the year, have made it a favorite amongst Costa Ricans. In fact, it was declared National Tree by the Costa Rican government.
It's called elephant-ear tree in parts of North America, given the particular shape of its pods. Other common names in the region include "devil's ear", "ear tree", "parota", "orejon" (big ear) and huanacaxtke (in Nahuatl). In el Salvador it is also known as conacaste.
These trees can delay development of their fruits to make it coincide with the rainy season. This adaptation allows the saplings to develop their roots before the start of the next dry season. Guanacastes, as many other deciduous or semi-deciduous trees in this region of the world, reduce water loss during the dry season by shedding their leaves.
The flowers of the guanacaste tree are visited by many types of bees, which also pollinate the trees. The pods, however, are mostly ignored by local animals and build up under the adult trees. The seeds are not usually consumed by local fauna either. It's possible that this unusual pods were sometime consumed by the Pleistocene mega-fauna that inhabited this region some 10,000 years ago. In this scenario, these trees survive today without the help of their original dispersion vectors, aided only by the artificial distribution favored by man.
The guanacaste is one of the most majestic and aesthetically pleasing trees in its geographical range. It can survive a wide range of rainfall, temperature and soil conditions, living in most dry lowland tropical habitats. These trees are highly valued as ornamental plants, and the shade that the wide canopy casts can offer a true oasis in the middle of hot and dry North Pacific lowlands.
It is commonly used for shade in coffee plantations or as shade and fodder tree for cattle ranches; it also helps in replenishing the soil's nutrients by fixing nitrogen.
The guanacaste tree was declared Costa Rica's National Tree on August 31st, 1959, by the government of Mario Echandi Jimenez.
The tree was chosen as a tribute to the province of Guanacaste, to celebrate their decision to join the country in 1824. It was also chosen for its great beauty and its protective shade, which symbolizes how the government cares for and protects its people.
The word 'guanacaste' derives from the Nahuatl language, where 'guautil' means tree, and 'nacaztli' means ear; this because its pods resemble a human ear in their shape.
In the wild, it is common on both the Pacific and Caribbean coasts, but it is much more abundant on the dry lands of the North Pacific.