Balsa

The balsa tree, Ochroma pyramidale, is a hardwood, leaf-tree that grows naturally in the humid rain forests of Central and South America. Its natural range extends south from Guatemala through Central America to the north and west coast of South America as far as Bolivia. Plantations in Ecuador are the primary source of most balsa.

Balsa in Spanish means raft; the name likely originated when early Spanish explorers found the natives using this wood for rafts. Extremely lightweight, balsa wood has excellent flotation.

Today, balsa wood is the miracle material of the hobby world. It has the best strength-to-weight ratio of any other readily available material.

The growth rates of the balsa tree are incredibly fast; in six to 10 years an average tree is 60 to 90 feet tall, with a diameter of 36 inches or more. Because of this, the tree was considered more of a weed in the 19th century than a timber species. Trees older than 10 years or much larger than 45 inches in diameter begin to develop wood that is much denser and harder than the early grown wood and the core begins to rot. Early harvest is required for the best wood. Note: The rain forests aren't being destroyed to harvest balsa wood.

Balsa wood has many commercial uses. Because of its insulating properties, it is used for lining incubators, refrigerators and cold storage rooms. Its sound absorption makes it a good choice for airplanes and modern speakers. It has long been used in making model airplanes and toys.

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About the author
Gene Wengert

Gene Wengert, “The Wood Doctor” has been training people in efficient use of wood for 45 years. He is extension specialist emeritus at the University of Wisconsin-Madison.