Uses: They are useful ornaments and shade providers to people, grazing cattle, and crops (namely coffee plantations). They have a reddish-brown wood that is lightweight and water-resistent, often used for doors, windows, furniture, cabinets, and ships. In Costa Rica, the seeds are used for jewelry. Its strong roots, fast growth (over a meter in its first year of life), and plentiful seeds make it a perfect candidate for reforestation initiatives. It is the national tree of Costa Rica.

Characteristics: 

It is medium-large height, growing around 25-35 meters tall (82-115 feet) and trunk with a 3.5 meter (11 feet) diameter, but, unusually, it completely lacks buttresses. Its bark is light grey and has red fissures that run vertical in its trunk, more prominent in saplings. When it has more space, the Guanacaste has a wide, spreading crown, but in the rainforest, where space and light is lacking, it is taller with shorter branches. It has bipinnate compound leaves, 15-40 centimeters (6-16 inches) long and 17 centimeters (7 inches) wide, oblong with 40-70 leaflets. The flowers are 5 millimeters long, and 50 flowers make up spherical white heads supported by a pedestal. They only have 20 stamens and a pistil, and when they blossom, their fragrent smell is very noticeable in the air. The fruits don't grow for nine months, until December. In February-March, they are fully grown, a year after the flowers blossomed and were pollinated by bees. The fruits contain 8-20 spirally arranged seeds in 7-12 centimeter (3-5 inch) pods that are very strong and resemble stones both physically and in strength. Their seeds' dispersers (giant ground sloths, giant bison, and more) are extinct, so they need humans to disperse and puncture their seeds. 

Threats: An insect pest in the Costa Rican Central Valley deposits spherical green galls on new shoots, in February and March. Ironically, in some places, the Guanacaste is considered an invasive species. Due to its tolerance of a wide range of precipitaion and soil conditions, it grows many places and isn't under much threat to its population.

Photo Credits:

http://www.inriodulce.com/links/Guanacaste.html

http://www.beachbeans.com/jewelry/guana_neck.html

http://www.govisitcostarica.com/blog/post/elephant-ear-tree-history-costa-rica-national-tree.aspx

http://www.govisitcostarica.com/region/city.asp?cID=4

http://magicaltrees.org/native-tree-gallery/

http://botany.csdl.tamu.edu/FLORA/imaxxmim.htm