5. Consider its history.

Many times we forget common sense and logic when attempting to identify wood. If you’ve got a piece of Amish furniture from Pennsylvania, chances are more likely that the wood will be made of something like black walnut or cherry, and not African wenge or jatoba. You might call it “wood profiling,” but sometimes it can pay to be a little prejudiced when it comes to wood identification. Some common-sense questions to ask yourself when trying to identify a piece of wood:

Where did it come from?

Knowing as much as you can about the source of the wood—even the smallest details—can be helpful. If the wood came from a wood pile or a lumber mill where all the pieces were from trees processed locally, then the potential species are immediately limited. If the wood came from a builder of antique furniture, or a boat-builder, or a trim carpenter: each of these occupations will tend to use certain species of woods much more often than others, making a logical guess much simpler.

How old is it?

As with the wood’s source, its age will also help in identification purposes. Not only will it help to determine if the wood should have developed a natural patina, but it will also suggest certain species which were more prevalent at different times in history. For instance, many acoustic guitars made before the 1990s have featured Brazilian rosewood backs/sides, yet due to CITES restrictions placed upon that species, East Indian rosewood became a much more common species on newer guitars. (And this is a continuing shift as newer replacements are sought for rosewoods altogether.)

How large is the piece of wood?

Some species of trees are typically very small—some are even considered shrubs—while others get quite large. For instance, if you see a large panel or section of wood that’s entirely black, chances are it’s either painted, dyed, or stained: Gaboon ebony and related species are typically very small and very expensive.

What is the wood’s intended use?

Simply knowing what the wood was intended for—when considered in conjunction with where it came from and how old it is—can give you many clues to help identify it. In some applications, certain wood species are used much more frequently than others, so that you can make an educated guess as to the species of the wood based upon the application where it was used. For instance, in the United States: many older houses with solid hardwood floors have commonly used either red oak or hard maple; many antique furniture pieces have featured quartersawn white oak; many violins have spruce tops; many closet items used aromatic red cedar, and so forth. While it’s not a 100% guarantee, “profiling” the wood in question will help reduce the number of possible suspects, and aid in deducing the correct species.

6. Find the X-Factor.

Sometimes, after all the normal characteristics of a sample have been considered, the identity of the wood in question is still not apparent. In these instances—particularly in situations where a sample has been narrowed down to only a few possible remaining choices—it’s sometimes helpful to bring in specialized tests and other narrower means of identification.

The following techniques and recommendations don’t necessarily have a wide application in initially sorting out wood species and eliminating large swaths of wood species, but will most likely be of use only as a final step in special identification circumstances.

Odor

Believe it or not, freshly machined wood can have a very identifiable scent. When your eyes and hands can’t quite get a definitive answer, sometimes your nose can. Assuming there is no stain, finish, or preservative on or in the wood, quickly sand, saw, or otherwise machine a section of the wood in question, and take a whiff of the aroma.

Although new scents can be very difficult to express in words, many times the scent of an unknown wood may be similar to other known scents. For instance, rosewoods (Dalbergia spp.) are so named for their characteristic odor that is reminiscent of roses. Although difficult to directly communicate, with enough firsthand experience scents can become a memorable and powerful means of wood identification.

Fluorescence

While certain woods can appear basically identical to one another under normal lighting conditions, when exposed to certain wavelengths—such as those found in blacklights—the wood will absorb and emit light in a different (visible) wavelength. This phenomenon is known as fluorescence, and certain woods can be distinguished by the presence or absence of their fluorescent qualities. See the article Fluorescence: A Secret Weapon in Wood Identification for more information.

Chemical Testing

There are only a small number of chemical tests regularly used on wood, most of which are very specialized and were developed to help distinguish easily confused species with one another. They work by detecting differences in the composition of heartwood extractives. A chemical substance (called a reagent) is usually dissolved in water and applied to the wood surface: the surface is then observed for any type of chemical reaction (and accompanying color change) that may occur. Two of the most useful are the tests that are meant to separate Red and White Oak, and Red and Hard Maple.

Heartwood Extractives Leachability

Sometimes a wood species will have heartwood extractives that will be readily leachable in water and capable of conspicuously tinting a solution of water a specific color. For instance, the heartwood extractives contained in osage orange (Maclura pomifera) contain a yellowish-brown dye that is soluble in water. (This can sometimes be observed anecdotally when the wood is glued with a water-based adhesive: the glue’s squeeze-out is an unusually vibrant yellow.)

In a simple water extract color test, wood shavings are mixed with water in a vial, test tube, or other suitably small container, and the color of the water is observed after a few minutes. If the heartwood extractives are leachable by water, then a corresponding color change should quickly occur.

In addition to osage orange (Maclura pomifera), merbau (Intsia spp.), and rengas (Gluta spp. and Melanorrhoea spp.) are also noted for their readily leachable heartwood extractives. Because this property is quite uncommon, it can serve to quickly differentiate these woods from other lookalikes.