WOOD IDENTIFICATION THROUGH WOOD ANATOMY with no more than a 10X loupe
A note about this article: this is a particularly oriented look at wood anatomy. Specifically, my concern is with anatomical features that are useful in identifying wood in an average shop that has no more equipment than a good sander and a 10X loupe. Stuff that requires a microscope is of no interest to me, although some such elements may be discussed to help in the discussion of the more macro-sized elements. My orientation throughout is that of a wood craftsman.
SO ... Botanists and wood scientists may grit their teeth at my occasional "layman-ization" of wood terms and my very brief discussion of micro constructs in wood, but botanists and wood scientists are not my audience. For example, I will say "end grain cross section" because that sounds much more natural to a woodworker than the formal term of "transverse cross section", and I will do little more than give a brief definition for terms that concern anatomical constructs that are not visible with nothing better than a 10X loupe and constructs that are ONLY visible (and meaningful) at the micro level, I'll pretty much ignore completely.
Wood craftsmen on the other hand may think that I sometimes go too far towards the technical in giving the descriptions here, but that's tough --- concise and accurate terminology tends to be technical in nature and my advice is, learn the terms if you want to understand wood anatomy even at the layman level. To a non-woodworker a term like "Forstner bit" sounds like Greek, but YOU know what it means don't you?
Terms regarding wood anatomy are usually discussed based on one of three planes. Technically, these are called the tangential plane, which corresponds to flat cut, the radial plane, which corresponds to quartersawn, and the transverse plane, which corresponds to the end grain. Also, the basic orientation of the cells in wood are radial (going from the center of the tree out to the bark) and axial (running up and down the height of the tree). Longitudinal is another word for axial and the two words are used interchangeably in the context of wood anatomy. Tangential is longitudinal cut, offset such that it doesn't pass through the pith.
tangential plane (flat cut)
radial planes (quartersawn)
transverse plane (end grain)
Illustration orientations: unless otherwise stated or when completely obvious, all of the illustrations in this article that contain growth rings are oriented with early growth nearer the bottom and late growth nearer the top. Stated another way, they are oriented looking down into the bole (or stump) of a tree with the bark of the tree upwards (which would be outwards when looking down the bole) and the pith downwards (which would be inwards when looking down the bole.
Illustration sizes: unless otherwise stated or when completely obvious, all of the illustrations in this article are 1/4" x 1/4" sections shown here at 12X.
What is needed: To make good use of the information in this article, you'll need at a minimum, a good sander with which to fine-sand the end grain of the piece you are trying to identify and a 10X loupe so that you can see the details in the end grain. If you're even more ambitious and don't mind risking cutting your thumb off, doing a razor cut on a small section of the end grain will give an even cleaner view of the details although it will have a limited size so may not give a full picture of the anatomical features.
The point of it all: The idea behind this site is basically as follows. Let's take two cases. In the first case, you have a wood that you can't ID but you have a good idea of what it might be. Say for example that it's obviously ring porous but doesn't have strong rays so you figure it could be ash, hickory, or chestnut. With that small a range of likely suspects you are better off just checking out those woods on the main site and if it's one of them you'll get it. If it's not, then this becomes like case #2, which is that you pretty much have not got a clue. In THAT case, this anatomy discussion will probably help you hone in on it, albeit with some tedium. First you have to clean up the end grain really well and then you have to go out and buy a 10X loupe (Hey, you should HAVE one already!) and then you have to figure out whether the wood is ring porous or diffuse porous or semi-whatever. Then you just poke around on the appropriate pages and with luck, you'll see a modest number of woods that seem like good candidates. With a lot of luck you might see only one or two. The parenchyma pages may also give good clues if the wood does in fact have some obvious parenchyma. Then you go BACK to the main page for those woods and see if the face grain seems to be a match on one of them.
There are two main sections, parenchyma and growth rings. Other information is planned but will be much less useful than the two main sections so I'm in no rush.
PARENCHYMA (primarily in hardwoods, minor in softwoods)
the full discussion provides an extensive discussion of the various kinds of parenchyma cells with lots of examples
a summary discussion --- if you're in a hurry, this provides an introduction to the major concepts of growth rings
the full discussion including extensive examples and, more importantly, with links at the bottom of that discussion page to 3,300+ end grain images which is the real utility of my anatomy pages. The images are broken down as ring porous etc and with sub sections that make it easier to hone in on the ID of a mystery wood