by Eric Meier
When attempting to identify a wood sample, it’s important to keep in mind the limitations and obstacles that are present in our task. Before starting, please have a look at The Truth Behind Wood Identification to approach the task in a proper mindset; I consider the linked article to be required reading for all those visiting my site with the intent of identifying wood.
1. Confirm it is actually solid wood.
Before proceeding too much farther into the remaining steps, it’s first necessary to confirm that the material in question is actually a solid piece of wood, and not a man-made composite or piece of plastic made to imitate wood.
- Can you see the end-grain? Manufactured wood such as MDF, OSB, and particleboard all have a distinct look that is—in nearly all cases—easily distinguishable from the endgrain of real wood. Look for growth rings—formed by the yearly growth of a tree—which will be a dead-giveaway that the wood sample in question is a solid, genuine chunk of wood taken from a tree.
- Is it veneered? If you see a large panel that has a repeating grain pattern, it may be a veneer. In such cases, a very thin layer of real wood is peeled from a tree and attached to a substrate; sometimes the veneer can be one continuous repeating piece because it is rotary-sliced to shave off the veneer layer as the tree trunk is spun by machines. Assuming it is a real wood veneer with a distinct grain and texture—and not merely a piece of printed plastic—you may still be able to identify the outer veneer wood in question, but you should still realize that is it only a veneer and not a solid piece of wood.
- Is it painted or printed to look like wood? Many times, especially on medium to large-sized flat panels for furniture, a piece of particleboard or MDF is either laminated with a piece of wood-colored plastic, or simply painted to look like wood grain. Many of today’s interior hardwood flooring planks are good examples of these pseudo-wood products: they are essentially a man-made material made of sawdust, glues, resins, and durable plastics.
2. Look at the grain color.
Some questions to immediately ask yourself:
- Is the color of the wood natural, or is it stained? If there is even a chance that the color isn’t natural, the odds are increased that the entire effort of identifying the wood will be in vain.
- Is it weathered or have a patina? Many woods, when left outside in the elements, tend to turn a bland gray color. Also, even interior wood also takes on a patina as it ages: some woods get darker, or redder, and some even get lighter or lose their color; but for the most part, wood tends to darken with age.
- Is it possible to sand or plane the board to see the natural raw color of the wood? The most predictable baseline to use when identifying wood is in a freshly sanded state. This eliminates the chances of a stain or natural aging skewing the color diagnosis of the wood.
3. Look at the grain pattern.
If the wood is unfinished, then look at the texture of the grain. Ask yourself these questions:
- Does the wood have an open, porous texture? Most softwoods will be almost perfectly smooth with no grain indentations, while many common hardwoods have an open pore structure, such as Oak or Mahogany; though there are some hardwoods that are also smooth to the touch, such as Maple.
- Can you tell if the wood is quartersawn or plainsawn? By observing the grain patterns, many times you can tell how the board was cut from the tree. Some wood species have dramatically different grain patterns from plainsawn to quartersawn surfaces. For instance, on their quartersawn surfaces, Lacewood has large lace patterns, Oak has flecks, and Maple has the characteristic “butcher block” appearance.
- Is there any figure or unusual characteristics, such as sapwood, curly or wild grain, burl/knots, etc.? Some species of wood have figure that is much more common than in other species: for example, curly figure is fairly common in Soft Maple, and the curls are usually well-pronounced and close together. Yet when Birch or Cherry has a curly grain, it is more often much less pronounced, and the curls are spaced farther apart.
4. Consider the weight and hardness of the wood.
If it’s possible, pick the piece of wood up and get a sense of its weight, and compare it to other known wood species. Try gouging the edge with your fingernail to get a sense of its hardness. If you have a scale, you can take measurements of the length, width, and thickness of the wood, and combine them to find the density of the wood. This can be helpful to compare to other density readings found in the database. When examining the wood in question, compare it to other known wood species, and ask yourself these questions:
- Is the wood dry? Wood from freshly felled trees, or wood that has been stored in an extremely humid environment will have very high moisture contents. In some freshly sawn pieces, moisture could account for over half of the wood’s total weight! Likewise, wood that has been stored in extremely dry conditions of less than 25% relative humidity will most likely feel lighter than average.
- How does the wood’s weight compare to other species? Taking into account the size of the board, how does its weight compare to other benchmark woods? Is it heavier than Oak? Is it lighter than Pine? Look at the weight numbers for a few wood species that are close to yours, and get a ballpark estimate of its weight.
- How hard is the wood? Obviously softwoods will tend to be softer than hardwoods, but try to get a sense of how it compares to other known woods. Density and hardness are closely related, so if the wood is heavy, it will most likely be hard too. If the wood is a part of a finished item that you can’t adequately weigh, you might be able to test the hardness by gouging it in an inconspicuous area. Also, if it is used in a piece of furniture, such as a tabletop, a general idea of its hardness can be assessed by the number and depth of the gouges/dings in the piece given its age and use. A tabletop made of pine will have much deeper dents than a tabletop made of Oak. Additionally, you can always try the “fingernail test” as a rough hardness indicator: find a crisp edge of the wood, and with your fingernail try to push in as hard as you can and see if you’re able to make a dent in the wood.
5. Consider the source.
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, yet due to CITES restrictions placed upon that species, East Indian Rosewood has become much more common on newer guitars.
- 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: 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.
7. Look at the endgrain.
Perhaps no other technique for accurate identification of wood is as helpful and conclusive as the magnified examination of the endgrain. Frequently, it brings the identification process from a mostly intuitive, unscientific process into a predictable, repeatable, and reliable procedure.
Looking at the endgrain with a magnifier shouldn’t be a mystifying or esoteric art. In many cases, it’s nearly as simple as examining small newsprint under a magnifying glass. There are three components necessary to reap the full benefits contained in the endgrain:
1. A prepared surface. When working with wood in most capacities, it becomes quickly apparent that endgrain surfaces are not nearly as cooperative or as easily worked as face grain surfaces. However, in this case, it is absolutely critical that a clear and refined endgrain surface is obtained.
For a quick glance of a softwood sample, a very sharp knife or razor blade can be used to take a fresh slice from the endgrain. However, in many denser species, especially in tropical hardwoods, one of the best ways to obtain a clear endgrain view is through diligent sanding. It’s usually best to begin with a relatively smooth saw cut (as from a fine-toothed miter saw blade) and proceed through the grits, starting at around 100, and working up to at least 220 or 320 grit, preferably higher for the cleanest view.
2. The right magnifier. It need not be expensive, but whatever tool is used to view the endgrain should have adequate magnifying power. In most instances, 10x magnification is ideal, however, anything within the range of 8 to 15x magnification should be suitable for endgrain viewing. (Standard magnifying glasses are typically in the range of 2 to 4x magnification.)
These stronger magnifiers, sometimes called loupes, usually have a smaller viewing area than standard magnifying glasses. Fancier models—with built in lights, or larger viewing surfaces—are available at a premium; but the most basic models are usually only a few dollars.
3. A trained eye. The third element that constitutes a proper endgrain examination is simply knowing what to look for. In analyzing the patterns, colors, shapes, and spacing of the various anatomical features, there is a veritable storehouse of information within the endgrain—all waiting to be unlocked. Yet, if these elements have not been pointed out and learned, the array of features will simply seem like an unintelligible jumble.
The discipline of recognizing anatomical endgrain features is not easily summed up in a few sentences or even a few paragraphs, but it is nonetheless critical to the identification process. To this end, an in-depth look should be given to the various categories, divisions, and elements that constitute endgrain wood identification on the macroscopic level. (In this regard, macroscopic denotes what can be seen with a low-powered, 10x hand lens—without the aid of a microscope—rather than simply what can be seen with the naked eye.)
Because the anatomy between softwoods and hardwoods is so divergent, each will be considered and examined separately:
- If you have a mysterious piece of wood that you’d like identified, I would recommend contacting the Center for Wood Anatomy Research, (part of the USDA’s Forest Products Laboratory), for a free, reliable, and professional identification. This is a free service available to all US citizens: they will identify up to five wood samples per year. See their Wood ID Factsheet.
- Check out the list of the most common hardwoods used in the United States to help eliminate the most obvious choices.
- For somewhat immediate gratification, you can post ID requests to the Wood Database Facebook page, and be sure to include picture(s), and any pertinent information you may have!