BALSA  

The balsa, Ochroma pyramidale, is a tropical American tree of the Bombax family, Bombacaceae, found in the West Indies and Central and South America. It is best known for its low-density and lightweight wood. The peoples who navigate the coastal and inland waters of Central and South America have used it extensively for canoes and rafts. In 1947 the anthropologist Thor HEYERDAHL went to Peru, built a raft of balsa logs, and with five companions sailed it from the port of Callao across the Pacific Ocean to the Tuamotu Islands in the South Pacific.

Balsa trees may grow to a height of 18 m (about 60 ft), with the trunk growing up to 76 cm (30 in) in diameter in about six years. They are now produced most successfully in plantations. The properties of balsa wood are much like those of CORK; most of its commercial use exploits its insulating qualities against heat or cold, its lightness for flotation equipment, and its capacity for deadening sound or mechanical vibrations. It is widely used for toys and for model building.