Balsa / Ochroma lagopus
Balsa is a deciduous tree found mainly in the tropical rain forests of Central and South America, and the West Indies. The cross-section through a trunk shows an almost white sapwood section which is hardly different in appearance to the reddish white heartwood section. The long-fibred wood distinguishes itself by its extremely low weight: it is barely heavier than bottle cork. Its pale reddish-brown colour darkens strongly with age, but it can be protected against light influences by applying UV absorbers. Surface treatment of this not very stable wood does not cause any problems. Varnishing, however, does not produce a lasting film if exposed to the weather.
Balsa wood can only be cleanly processed with very sharp and flat cutting implements. It tends to tear easily and cannot be joined with nails or screws, although it can be glued rather easily.
Balsa is mainly used in model making and as insulation material.