How
It Works
Many people are familiar with woods such as rosewood, with its rich color, that varies from light to dark brown, with black streaks, and sometimes red. Many are also acquainted with or even possess carvings made from ironwood, perhaps brought home as souvenirs from a vacation in the American southwest or in Mexico. Most of us know that a fence built from cedar is able to withstand the weather's worst for many years. Not so many know that these names are completely made up; arbitrarily applied to any given species of wood because such a name conjures images of a material that is perhaps gem-like in its luster and beauty, or as refractory as the best products of human industry, or as fragrant as incense, or perhaps it simply sounds exotic -- the imported produce of a far off land. Thus several species of Shorea became known in the lumber industry as Philippine mahogany, and any species with soft wood and an earthy, spicy scent became known as cedar.
Names such as cedar, pine, oak, rosewood, ironwood, mahogany, cherry, walnut, and teak may be applied to any number of tree species from almost any continent (Antarctica being one obvious exception). These names are about as precise as saying that my mailing address is California, USA. The name "ironwood" is generally applied to the hardest, toughest, most ornery wood from a given region, thus there is Texas ironwood, Arizona ironwood, California desert ironwood, Mexican desert ironwood, and so on, each of which could, in turn, refer to several different species of trees and shrubs. The name "rosewood" is given to many trees of the genus Dalbergia, which tend to possess generally similar characteristics of hardness, fragrance, and luster, but vary widely in other respects, such as actual color and suitability for use in, for example, musical instruments. Mahogany originally referred to certain species from Central America and the Caribbean, but its reputation as an excellent wood for boatbuilding and fine furniture led to the name being applied to several related African species and, later, to several un-related species called Phillippine mahogany (a.k.a. Lauan), which does not have the hardness, decay resistance, strength, or price tag of the original. For woodworkers, it is highly desirable to have a more exact way of referring to the wood derived from a particular species of tree. A wooden ladder may be built from certain trees, but must not to be built from others, or it may break. And a boat made from "oak" will be either very sound or very leaky, depending on precisely which of the 50 or so species of oaks that are native to North America were used in its construction. Thus the woodworking industry turns to science to solve its problems.
Latin names, or scientific names, are absolutely unique to each plant and animal species; thus if our boat is made from Quercus alba, one of the group known to the trades as white oak, we know it will be safe and sound. If Quercus velutina was used, we'll be doing a lot of bailing. The name taxonomy has been given to the systematic classification and identification of plant and animal species using Latin names. While the system is fluid, and individual timber species are re-classified (and renamed) periodically as botanists decide that a given species is really related to some other group of trees, the system of Latin names is the best way we have, as woodworkers, to refer to a specific species of wood in a way that is not ambiguous and subject to the vagaries of geographic variation and "cosmetic upgrades" by corporate marketing departments. Another advantage to using scientific names to organize information about wood species is that related species will naturally be grouped together when sorted by scientific name. Thus woods such as tulipwood, cocobolo, kingwood, African blackwood, and the various rosewoods of the Dalbergia genus, including East Indian, Madagascar, Bolivian, and Brazilian rosewood, would all be grouped together by Latin name, making comparisons between related species relatively easy.
How
It Works
All living things are classified according to a commonly agreed-upon system, so scientists around the world can talk about a given plant or animal species and know exactly what is being referred to. The system branches like a tree (isn't that nice?), so the first division of living things is between the plant kingdom and the animal kingdom, then each kingdom is subdivided into different subgroups, and so on. As woodworkers, however, we don't need to know the difference between an order and a phylum; or know what sensu lato means. The important parts are the last few subdivisions. A tree is referred to by a two-part latin name (sometimes called a binomial name). The first part is the genus; for example, Quercus for oak, or Pinus for pine. The genus identifies the particular family (immediate relations), and the second part of the name identifies the species; for example, Quercus velutina is black oak, and Pinus strobus is Eastern white pine. (For all the grammar and spelling nuts like myself, the latin name is always italicized, the genus is always capitalized, and the species is never capitalized. Also, the singular of species is species; the term "specie" refers to coins.)
For more convenient classification of the 50,000 or more tree species, we also have families, which group species together into extended families of related cousins, aunts, and uncles. Examples include Fagaceae (pronounced FAG-uh-SEE-uh or FAY-guh-SEE-uh by most woodworkers), the beech family, for beeches, oaks, chestnuts, etc.; or Pinaceae (PINE-uh-SEE-uh) for the pines, larches, spruces, firs, hemlocks, and so on. Finally, the largest subdivision we, as woodworkers, care about is the order. This is where hardwoods like oak are separated from softwoods, like pine, and woody monocots, like palm and bamboo.
The important thing to take away from all of this is that the common name
is a pretty lousy way to refer to wood species when you're looking for particular
properties, such as hardness, strength, decay resistance, toxicity, etc.
Common names are completely arbitrarily applied and ambiguous, but
scientific names, by definition, refer to one species. Only
one species. With physical properties that may vary from one tree to
the next, but will always vary within bounds dictated by the plant's DNA.
References:
Understanding Wood and Identifying Wood, R. Bruce Hoadley, Taunton Press, 1980 and 1990, respectively.