Tree ( Ochroma pyramidale , or O. lagopus ) of the bombax family (Bombacaceae), native to tropical South America and noted for its extremely light wood, which resembles clear white pine or basswood .
Because of its buoyancy (about twice that of cork), balsa has long been used for making floats for lifelines and life preservers. Its resilience makes it an excellent shock-absorbing packing material. Its insulating properties make it a good lining material for incubators, refrigerators, and cold-storage rooms. Because it combines lightness and high insulating power, it is a valuable construction material for transportation containers for dry ice (solidified carbon dioxide). It is also used in the construction of airplane passenger compartments and in model airplanes and boats.