Balsa (Ochroma lagopus, synonym O. pyramidale) is a large, fast-growing tree to 30 m tall, native from tropical South America north to southern Mexico. It is evergreen, or dry-season deciduous if the dry season is long, with large (30–50 cm) weakly palmately lobed leaves. The name balsa derives from Spanish for "raft."

The timber is very soft and light with a coarse open grain. The density of balsa wood ranges from 100–200 kg/m³, with a typical density of about 140 kg/m³ (about one third the density of ordinary wood). This makes it a very popular material for model making and buoyancy materials (lifebelts, etc.), and was famously used by Thor Heyerdahl in his raft, Kon-Tiki. It is also used to make very light, stiff structures in full-scale wooden light airplanes, typically sandwiched between two pieces of thin plywood.

Despite being very soft, balsa is classified as a hardwood, the softest commercial hardwood.

Three different sizes of balsa wood used for hobby purposes

Frame of a model airplane constructed entirely of balsa wood

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External linksEdit

• Species description
• Photo of foliage and flower
• Kon-Tiki museum website
• ITIS 21602

TaxonomyEdit

• Name = Balsa
• Regnum = Plantae
• Division = Magnoliophyta
• Classis = Magnoliopsida
• Ordo = Malvales
• Familia = Malvaceae (Bombacaceae)
• Genus = Ochroma
• Species = O. lagopus
• Binomial = Ochroma lagopus
• Binomial authority = Sw.