Tree (Ochroma pyramidale, or O. lagopus) of the mallow family (Malvaceae), 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.