Hawaiian koa is one of the most expensive and rarest commercial woods in world. But you can afford to walk all over it-or at least you can walk on its cousin.
Last week I referenced Acacia as one of the trendy plantation woods in the flooring industry. Acacia is actually the genus, and it covers a VERY wide number of trees. Koa is the species for the Hawaiian version. That's one. However, there are somewhere between 950 and 1,300 species of Acacia in the world. According to the Wikipedia entry, even scientists aren't too sure how to define Acacia:
The genus Acacia previously contained roughly 1,300 species, about 960 of them native to Australia, with the remainder spread around the tropical to warm-temperate regions of both hemispheres, including Europe, Africa, southern Asia, and the Americas. However, in 2005 the genus was divided into five separate genera. The name Acacia was retained for the majority of the Australian species and a few in tropical Asia, Madagascar and Pacific Islands. Most of the species outside Australia, and a small number of Australian species, were reclassified into Vachellia and Senegalia. The two final genera, Acaciella and Mariosousa, only contain about a dozen species from the Americas each….
…Consequently, the name Acacia is conserved for 948 Australian species, 7 in the Pacific Islands, 1 or 2 in Madagascar and 10 in tropical Asia. Those outside Australia are split between the genera Acaciella, Mariosousa, Senegalia, and Vachellia. However, there is an effort underway to reverse the 2005 decision, due to be discussed at the 2011 Congress.
(None of that even considers the possible confusion with some regarding American black locust of the Robinia family, which is scientifically known as Robinia pseudoacacia, or "false acacia"…)
In Asia, most flooring is made from one of two primary species: what is often called "small leaf," Acacia confusa, and the "big leaf," Acacia mangium. I believe that the 'confusa' version, which is native to Asia, is named after Confucius, but it certainly could be named after the general confusion about this wood.
You might also find flooring made from auriculiformis, chinensis, or several others, but most of the market is from confusa or mangium. Sometimes the species are intermixed just as what we call red oak commercially can actually be dozens of oak species, but more often then not, because it's a plantation wood, you'll a single species per product.
The confusa species has a long history of alternative uses in Asia. A bit denser then its mangium cousin, it has served as a "pillar" of the mining community for decades, as well as being used in charcoal production. It also has a key place in traditional Chinese medicines and is being studied as a treatment for hepatitis C.
Mangium originated in Australia, where it is also know as black wattle. It grows a little faster and has slightly wider growth rings as a result. Planted widely throughout Asia, it is drought-resistant and grows where many other trees fear to set down roots.
Both make beautiful floors and will provide a lifetime of use to your families. A nice visual comparison of some of the Acacia species is available at: www.ctahr.hawaii.edu/forestry/trees/Acacia_Azadirachta.html and a wood use review can be found here: www.thewoodexplorer.com/specieslist1.php.
(Pictured is Acasia confusa offered by Kentwood.)