For what special purpose is Pernambuco wood traditionally used?

“Paubrasilia echinate” is a species of flowering plant in the legume family, “Fabaceae,” endemic to the Atlantic Forest of the state of Pernambuco, Brazil. It yields timber known as Pernambuco wood (Portuguese: “pau-de-pernambuco”) and is the national tree of Brazil. The name “pau-brasil” was once applied to some species of the genus “Caesalpinia”, and was given its original scientific name “Caesalpinia echinate” in 1785 by Jean-Baptiste Lamarck. Recent taxonomic studies suggested that it merits recognition as a separate genus, and so it was renamed “Paubrasilia echinate” in 2016. The term “echinate” refers to a hedgehog and describes the thorns which cover all parts of the tree.

The plant has a dense, orange-red heartwood that takes a high shine, and it is the premier wood used for making bows for stringed instruments such as violins.

To make the stick of the bow a squared-off blank of Pemnambuco wood is held across the corner of a bench, and planed by hand with specially designed planes, fashioning the cross-section of the stick into its characteristic shape. Using a direct heat device such as a spirit lamp or gas burner, the stick is heated slowly until it becomes flexible enough to bend into a rough curve. The bow usually has no varnish because Pernambuco wood is inherently dark and oily. But the stick may be subjected to chemical treatment to achieve its characteristic chocolate brown colour and is given additional sheen and protection by French polishing.