Wood of the Week: Goncalo Alves
Botanical Background: Astronium fraxinifolium and Astronium
graveolens of the family Anacardiaceae. Common names: Goncalo Alves, zebrawood,
tigerwood, kingwood, bosona, uru nday-para, mura, and bois de zebre., chibatao,
guarita, urunday and aderno
Goncalo Alves belongs to the Sumac and Cashew (Anacardiaceae) family, which includes some 600 species around the world. Relatives of the tree include the tropical cashew, pepper trees, mangoes trees, pistachio trees, and poison ivy.
Variation: Goncalo Alves is sometimes referred to as
zebrawood or tigerwood — names that underscore the wood’s often dramatic,
contrasting color scheme. While the sapwood is very light colored, the
heartwood is a mix of deep red and brown, often with dark streaks and
colorations that give it a unique look that some compare to rosewood. The
wood’s color deepens with exposure and age and even the plainer-looking wood
has a natural luster. Goncalo Alves grows plentifully in the forests of Mexico,
Central America and in South American countries including Ecuador, Colombia,
Venezuela and Brazil. Brazil is a major exporter of the wood.
Of the two major species are usually listed as sources for Goncalo Alves; Astronium fraxinifolium and Astronium graveolens, the wood from the latter is usually more straight-grained, less dense, and slightly plainer in looks than the former. It's exceptionally fine textured and when it has an especially nice marble-like figure ( rust red, chocolate brown and creamy white veining), it is a strikingly attractive accent wood,touted as a substitute for rosewood.
The tree reaches a height of up to 120 feet (37 m), with a trunk diameter of 24 to 40 inches or more above narrow flanged buttresses that are about 4 to 6 feet (1.2 to 1.8 m) high. It develops well formed cylindrical boles that are often clear for about two-thirds or more of the total height of the tree.
The average specific gravity is 0.75 Green to Ovendry, putting up with other tropical hardwoods (Bloodwood =.73) and far above common North American Hardwoods (Walnut = .51, Cherry = .47), Shrinkage is: Radial = 4.0%, Tangential = 7.6%, Volumetric = 10.0%, making a a relatively stable wood. The weight is 53 to 80 lbs. per cu. ft.
Goncalo Alves is very hard and heavy, with a fine texture and sands to a glass-like finish. It can be difficult to work, but turns well and is quite durable and weather resistant.
The raw timber is difficult to dry with a tendency to warp and check. Experts recommend slow air drying. Shrinkage on drying is rated low. However, the wood has small movement once dry. The wood’s density and interlocked grain can make it difficult to work and can cause moderate to severe blunting of cutting tools. Cutting edges should be kept sharp. Wood is made of contrasting hard and soft material plus irregular or interlocked grain. Preboring is recommended for nails and screws. Goncalo Alves finishes well. Wood is highly durable, unaffected by moisture, insect and fungal attack, and extremely resistant to preservatives. It is not suitable for steam bending.
According to "Wood Handbook — Wood as an Engineering Material," published by the USDA, "The high density of the wood is accompanied by equally high strength values, which are considerably higher in most respects than those of any well-known United States species." However, the wood is not imported for its strength. In the U.S. market, Goncalo Alves is usually prized for its beauty. These properties lend it to utilitarian uses in the countries where Goncalo Alves grows. Heavy-duty applications include general construction, flooring and exterior joinery.
The wood is very oily, which causes problems with gluing.
Goncalo Alves is used to make the dampers in grand pianos, but the tree is also a source of beautiful lumber and veneer used in furniture, cabinetry, marquetry and specialty items such as billiard cue butts, archery bows, and jewelry boxes. It is also popular for turnery and carving. Veneers are used for architectural applications such as paneling. The distinctive-looking wood is often used with other woods as an accent.
I personally find Goncalo Alves to be one of the few woods with grain interesting enough to make a beautiful pen, yet not so over powering that it can't be used on a table.