The Rosewood genus; Dalbergia, belongs to the Legume family (Leguminosae). With somewhere around 14,000 species, this family is one of the largest and most diverse in the plant kingdom…and it produces so many fine timbers of such varied character that it is perhaps best to ignore the rest of the family and address the rosewoods strictly at the genus level. The genus, Dalbergia, is pan-tropic in distribution. While some botanists break this taxonomic grouping into several smaller genera, in its broadest interpretation Dalbergia contains approximately 250 species. They are mostly small shrubs or climbers and, even among the mere 15 to 20 species that produce commercially important cabinetwoods, none of them are truly huge trees in comparison to most other tropical timbers. Of these 15 to 20 species, about a third (6 to 7) are native to the Americas, while the balance are spread from western Africa eastward, through India and on into Indochina.
Color tends to be the primary distinguishing
attribute among the rosewoods. In fact, they have such strikingly vivid
pigmentation that the various species are more often thought of as completely
separate cabinetwoods. Brazilian tulipwood; D. fructescens, with its beautiful
creamy yellow and coral pink veining is perhaps the “blondest” of the bunch,
while African Blackwood; D. melanoxylon, is so dark it is an important
substitute for ebony. Virtually all of the remaining rosewoods have marbled or
striped figures, typically combining dark chocolate brown tones with lighter
highlights, ranging from the magenta purple found in Brazilian kingwood; D.
cearensis, to the bright orange streaks exhibited by cocobolo; D. retusa,
native to Central American. The balance of the rosewoods generally reveal
various hues of red. Two species found in Madagascar; D. greveana and D.
baroni, the darker of India’s rosewoods; D. latifolia, and the Southeast Asian
species; D. cochinchinensis, are similar in color to the now vary scarce Brazilian
rosewood; D. nigra…while the highlights in Honduras rosewood; D. stevensonii
and India’s sissoo;
D. sissoo, lean more to the brick orange or amber side of the spectrum, giving these last two species a noticeably lighter overall appearance.
There is some minor variation in both the texture and density of the rosewoods in that cocobolo and sissoo are somewhat coarser, but all of these timbers are perhaps best described as fine textured and exceptionally dense. Depending upon the species and growing conditions, they range from about 0.80 to above 0.90 in terms of specific gravity (in other words, they’re all about half again as dense as hard maple or white oak.) Also, they are all very oily woods with a sort of waxy luster and a pronounced floral or sometimes spicy scent. The fragrance is actually pleasant when faint, but the fine dust produced when shaping or sanding these woods can be irritating enough to cause watery eyes and/or respiratory problems.
The rosewoods have outstanding turning and shaping characteristics, are exceptionally stable and have excellent decay resistance. Their striking appearance makes them prized woods for use in decorative turnings, showy veneers, inlays and other accent applications…and, functionally speaking, some of them are unsurpassed for use as knife and tool handles, or for the fretboards on musical instruments. On the downside, however, their scarcity and high cost now limits their use in larger cabinetmaking applications. Also, they can be somewhat difficult woods to work with in other important respects. Their extreme density makes them hard on blades, their oiliness interferes with adhesives and finishes and they are potentially toxic. While in high doses, the scent becomes overpowering and plenty irritating for virtually all woodworkers, these Dalbergia species contain an extractive called dalbergione (a quinone ) which is a very potent allergen for some individuals. In fact, there are documented cases where musicians who experience only minimal exposure to the wood by way of skin contact with chin rests or fretboards while playing their instruments have developed serious and persistent skin rash.
Supply (and alternatives.)
Although the supplies of many valuable and prestigious tropical woods are declining at an alarming rate, the outlook for virtually all of the rosewoods is especially bleak. The highly selected and vividly pigmented heartwood of these species comes from only the most mature trees…in fact the color doesn’t seem to fully materialize until the tree actually starts to decline into decrepitude. Also, many of the better known rosewoods, such as those from Brazil and India are native to coastal forests where high human populations over literally centuries have heavily exploited the resource and where land is now too valuable for raising food crops to be dedicated to reforestation projects. As remaining stands of these timbers are harvested there is little likelihood they will be replenished in the near term…if ever.
There are no perfect substitutes for some of the fabulous color combinations found in the rosewoods, but there are many other very colorful woods worth consideration when an eye-stopping appearance is the objective. Several genera in the Legume family yield very colorful woods. For example, the genus Peltogyne provides about 20 moderately plentiful species of South and Central American purplehearts, the African and Asian members of the genus Pterocarpus (padauk and narra) yield vividly red timbers as does African bubinga in the genus Guibourtia. Also, while not part of the Legume family, the South American genus Cordia contains some very colorful members such as ziricote and bicote, both of which have beautifully striped figure…And finally, goncalo alves, a South American member of the Poison Ivy family (Anacardiaceae) produces a stunningly marbled figure, incorporating rust orange, dark brown and creamy white swirls. It is perhaps one of the best of the rosewood substitutes in that it is also exceptionally dense and fine textured.
Information developed by Jon Arno or Mark Kauder and posted by Mark on www.woodcentral.com . Mark has graciously given East Texas Woodturners permission to add the write ups to our site. Thanks Jon and Mark.