Cutting across stump and butt sections of trees sometimes produces a staircase-like, somewhat curly figure, that is commonly called "angel step". This occurs most frequently in walnut, but may occur in other woods such as ash and maple.
A small-scale, very tight, mottle figure is sometimes referred to as "bee's wing" figure due to the similarity with what the wing of a bee looks like. East Indian satinwood is extremely well known for having this figure, and it also occurs occasionally in narra, mahogany and eucalyptus. So when is a figure "block mottle" and when is it "bee's wing" ... well, pretty much whenever a particular dealer decides that's what they want to call it.
A few woods, most notably maple but also anigre and a few others, can exist with large numbers of small round "defects" that do indeed resemble the eyes of birds. The density of the eyes ranges from sparse to dense, and the definition of "dense" frequently depends on the greed and honesty of a seller, so this is not a good figure to buy sight unseen. A good, truely dense, bird's eye maple board can make a spectacular addition to a project; it is very popular for jewlery boxes. When cut into veneers, the logs are most often rotary cut or half-round sliced (in an arc) to produce the most uniform distribution of nice round eyes. There are a few woods that are sold as "bird's eye" with a density of eye figure so low as to make the term a joke. Zebrawood in particular comes to mind for his. Zebrawood veneer sheets that are sold as "bird's eye" are due to having literally 8 to 10 eyes in an area of 5 or 6 square feet.
A burl is a wartlike, deformed growth on the trunk or root and sometimes even the branches of a tree, caused by (1) an injury to, or (2) and infection in, the tree just under the bark, or (3) the existance of an unformed bud which has all the genetic material necessary to grow a full branch, or even a whole tree, but which for some reason did not grow properly. In any case, the result is that the tree cells divide and grow excessively and unevenly in a process somewhat analogous to cancer cells in a mammal. Burls are sometimes called tumors on wood, although I'm not aware of their ever being fatal. Trees with burls continue to grow otherwise normally. Continued growth follows the contour of the original deformity, producing all manner of twists, swirls and knots in the wood fiber. Usually, this results in wood that has a spectacular pattern that can be used to great effect in woodworking, and sometimes it is also accompanied by the creation in the burl of dormant buds which create "eyes" that make the burl even more spectacular when worked. Burl wood is usually darker than the rest of the tree and in some cases (Paela comes to mind) may be a significantly different color altogether. Because of the diverse grain direction, burl wood cannot be relied on for strength, but that's of little consequence since burls are prized for beauty, not strength. Burl wood can be difficult to dry without cracking. Sometimes there are bark inclusions in burls, and also sometimes gum pockets, either of which can cause surface defects when the burl is worked. In some species of wood, gum pockets are common in any burl found on the tree. Burls come in all sizes and shapes from golf-ball and smaller to hundreds of pounds of massive growth on the side of a large tree. Burls as large as 4 feet by 8 feet have been reported as have trees with hundreds of small burls. On really large trees, such as the redwood, burls commonly exist that are large enough to be used to create veneer. "Cat's Paw" and "cluster burl" are a couple of commonly identifed types of burl figure. Cat's paw is frequently found in cherry and cluster burls are found in a number of species. Most often, burls have no sub-designation and occur in a large number of species. Common burl species include redwood, oak, ash, madrone, elm and walnut. Some exotics with very popular burls are mappa, thuya and imbuya --- there are many more.
Cat's paw is a form of "pippy" wood or perhaps burl wood where the little dots occur in a pattern that is strongly similar to the pattern of a cat's paw (see how obvious the name is?). I've only seen it in cherry but it may occur in other woods. It is, in my experience, a very sparse pattern and an almost meaningless term as far as useful woodworking goes.
Compression wood is a portion of a tree where the wood fibers have been compressed due to stress in the tree. This can be caused by irreglar growth such as a tree that grows on a riverbank and then tilts as the bank slids into the water, causing the tree to have compressed wood in the side next to the water because the tree is bent over in that direction. Crotches are an extreme form of compression wood. They are caused by the forces exerted within the tree to support a main branch where it joins the trunk, and of course the bigger the branch, the more the compression. The compression decreases as one moves away from the point where the branch meets the trunk, so crotch wood frequently exhibits an extreme degree of grain variation. The compression process that strengthens the tree so it can support the branch causes the wood fibers to twist and compress, creating various figures and grains that can be very beautiful. Unlike burls, crotches have grain that, while quite distorted, is basically the same grain as the other wood in the tree and does not tend to the extreme swirls and eyes of burl wood, but even so, crotch wood can be wonderful to behold. Crotch wood is typically harder and more dense than a straightgrained portion of the same tree. Depending on the apprearance, a crotch may be called a "flame crotch" or a "feather crotch" (and less frequently as "plume", "roostertail" or "burning bush") and frequently the crotch area is somewhat symetrical on both sides of the branch so that a crotch piece cut parallel to the bole of the tree will produce a look similar to that of book matching. Terms such as "feather" and "flame" should not be relied on if you haven't actually seen the wood, as they are used VERY freely. I've seen one gun-stock maker who states on his web site that he always calls all crotches flame crotches because "it sounds more impressive". In veneers, crotch sheets are seldom found in larger sizes, and mahogany and walnut species dominate the field of crotch veneers because they are the main trees that consistently produce large crotch areas. In mahogany, enough veneer has been produced to be able to establish grain pattern types. Thus one can select a swirl, a feather, a rat-tail, and others. Mahogany has always been the classic crotch because of consistency, size, and soundness. The price range is moderate to expensive.
Contortions in grain direction sometimes reflect light differently as one moves down the grain and this creates an appearance of undulating waves known as curly grain. It is frequently described as looking like a wheat field in a mild wind, and can be so strong an effect that your eyes will swear that a flat piece of wood has a wavy surface. Many species develop this figure, maple being a very common example. Stump and butt sections of trees often produce a diagonal, staircase-like curl referred to as "angel steps", and a rolling curl figure that is called "cross-fire". An extreme form of curly figure is called "fiddleback". The amount of curl in a wood sold as "curly" can range from almost none to truely spectacular, so this is not a term to be trusted via mail order purchasing.
EARLY GROWTH / LATE GROWTH
Trees that grow in temporate zones (that is geographic regions where there is little change in climate throughout the year) grow pretty much the same amount every day and consequently have little variation in texture. Trees that grow in regions with seasonal climatic changes, however, grow at different rates during the seasons, ranging from exhuberant "early growth" in the spring and early summer, to a slower "late growth" in the late summer and fall, to essentially none in the winter. The early growth is typically wider, less dense, weaker, and more porous than the late growth and in many cases is significantly lighter in color. These early/late growth sections are what make up the growth "rings" ("annual rings") in trees. One tree that particularly shows this characteristic in a very striking way is Douglas fir. Since there is one growth ring per, the number of rings in a cross section show the age of a tree. Using both old dead trees and old live trees, scientists have dated events back for thousands of years based on tree rings.
Curly figure in wood (and fiddleback is just a variation of curly) is caused by contortions in grain direction such that light is reflected differently at different portions of the grain, creating an appearance of undulating waves, also called a "washboard" effect because it looks like an old corrugated-steel washboard. "Fiddleback" figure is a form of curly figure where the curls are very tight and fairly uniform, generally running perpendicular to the grain and across the entire width of a board. The name comes from the fact that such wood became popular to use on the backs of violins (fiddles), and nowadays guitars, because the figure is frequently very lively and attractive and such wood generally has good resonance properties. Logs for fiddleback veneers are quartersawn to produce very straight grain with curls running perpendicular to the grain and uninterrupted from edge to edge of the sheet. Some reports claim that a tree which buttresses itself against north winds will have compressed annular growth rings in the area facing north and expanded rings facing south and that the stress in the compressed rings is believed to cause the fiddle back figure. Many species develop this figure, but the most common ones are maple, makore, anigre, and "English Sycamore" (which is actually a form of maple). Some of the prettiest versions occur in claro walnut and koa. There are woods (laurel comes to mind) that have a figure that is technically a true fiddleback figure, but which is so light as to be almost indiscernable, and there are others that have fiddleback figure that only runs for a few inches of width in a plank although it may run the full length. None of these marginal figures would actually be used on the back of a fiddle, so application of that name to them is purely technical and/or a marketing ploy and should not be taken seriously. Also, plain curly is sometimes mislabled fiddleback and true fiddleback is sometimes labled as just curly, depending on the whims of the vendor.
Figure is the form of the grain and color patterns in wood that give it a unique apperance. There are many factors or characteristics that go into making up the figure, and some of the terms that are associated with figure are fiddleback, curly, wavy, tiger stripe, marbled, spalting, feather, flame, bee's wing, bird's eye, and more. The figure of woods is heavily influenced by how the wood is cut. Cutting terms to see include quartersawn, flat cut, rift cut, etc. Veneers have additional figure capabilites since they have an additional cutting style (rotary) that is not available to lumber.
Grain is the stripes in the wood created by growth rings which may be tight, indicating slow growth, widely spaced, indicating quick growth or any variation in between. Different woods have distinct grain patterns that help identify them. The grain is caused by the fact that trees in non-temperate zones of the world grow at different rates in the summer (late growth) than they do in the spring (early growth), and the density and coloration of the early and late growth can vary signifcantly. For a very graphic example of this, check out the coat rack shown in the pictures under Douglas Fir on this site. In temporate zones, there is no early and late growth, so the wood tends to have a uniform grain but may still have significant color variations. Growth rings tell how old a tree is, since there is one per year. This fact has been used with combinations of live trees and tree stumps to determine dates going back several thousand years. The appearance of the grain pattern in woods can be changed dramatically by making a different kind of cut in the wood. The main cut types are quartersawn and flat cut. In a flat cut, the cut is parallel to the pith but does not intersect it, and the resulting grain pattern sometimes has what is called a "cathedral" pattern that looks like a series of stacked "V" shapes, although it can be just a series of parallel lines that vary in spacing depending on their distance from the pith. In quartersawn, the cut is radial (that is, all cuts intersect the pith of the tree for the entire length of the cut) and the resulting pattern tends to be a series of totally parallel grain lines with spacing that is determined entirely by the amount of yearly growth.
There are two forms of mineral stains in wood. In the first form, wood roots will pick up tiny bits of dirt and as the tree grows, these move up into the tree and spread out slightly, producing small ugly stains in the wood. These are generally olive-green to dark brown. In the second form, the dirt disolves into the sap and produces a less emphatic but much larger area of stain, usually gray but sometimes a mottled brown. Both of these forms are very common in maple and the second is also common in poplar. This is possible with hickory and basswood.
Sometimes, wavy grain in a wood combines with spiral, interlocked grain to produce a wrinkled, blotchy figure known as mottle, which would be called "curly" if the curl lines were not so broken up. If the mottled figure is scattered randomly it is tecnically called "broken mottle" but if it appears as a regular checkerboard pattern it is called "block mottle", and a very regular, sharp, block mottle is called "razor mottle". Perhaps vendors think "broken mottle" carries a negative connotation, but in any event, the plain "mottle" is used instead. Anigre, makore, and sapele frequently exhibit all kinds of mottle figure, and it also occurs in mahogany, koa, bubinga, African satinwood and some other species. The various "mottle" terms are, like many terms regarding wood figure, used very loosely and should not be trusted sight unseen.
There is a form of blistered or pomelle figure found fairly often in Tamo (Japanese Ash) and less frequently in a few other woods, where the grain pattern forms into the classic shape of a peanut shell (the standard, common, kind with two peanuts in one shell). It has a very "busy" look but can be quite attractive
A form of "defect" or "character" (depending on how you look at it) in wood where it looks as though the wood has a bad (or sometimes mild) case of the measles, with little spots dotting throughout the grain. Occurs in yew and a few other woods. In England, there is a form of oak burl that is called "pippy oak" in which the burl characteristics are pretty much the same as what we Americans call pippy, but more dense.
A form of "defect" or "character" (depending on how you look at it) in wood where there are numerous spots or elongated areas throughout the wood caused by localized decay. It may also be caused by infection of the grown rings in which case it is best shown in rotary cut veneer because that cutting technique follow the growth rings. The term is also sometimes applied to a similar appearing figue that is an abrupt color change caused by localized injury such as actual bird pecks, and can look like a sparse bird's eye figure. Pecky can also look a lot like "wormy", in that it shows long fingers of discolored areas instead of just spots. Pecky cypress is of the wormy form and is highly prized for the decorative effect, although it is easy to see how some people could find it UNattractive (see the pictures). In hickory and pecan, the pecky figure is generally in the form of spots that look as though they could have been caused by a bird's pecking at the tree. In birch, pecky is of the "wormy" form and the wood isnot generally called "pecky" but rather has its own designation of "Karelian" or "Masur" birch and is a burl form. Karelian is generally applied to Scandinavian birch and Masur to American and European birch, but that is based on casual observation, not serious research.
Pomelle is a type of wood figure that resembles a puddle surface during a light rain: a dense pattern of small rings enveloping one another. Some say this has a "suede" or "furry" look. It's usually found in extremely large trees of African species like sapele, bubinga and makore. Some domestic species with a sparser, larger figure are referred to as "blistered". The term is not used totally reliably and you may encounter some confusion among the terms "blistered", "pomelle", and "quilted" from different vendors. The name Pomelle comes from the French word for "quilted", so it's not too surprizing to find this confusion. In sapele, there are even more confusing names used for variations among figure types including pomelle, so you may see "pomelle pebble", "pomelle swirl", "pomelle quilted" and other combination terms that are not necessarily used consistently among vendors. Spelling variations include "pommele", "pommelle", "pomelle", and "pomele"
Quilted figure somewhat resembles a larger and exaggerated version of pommele or blister figure but has bulges that are elongated and closely crowded. Quilted grain looks three-dimensional when seen at its billowy best. Most commonly found in maple, it also occurs in mahogany, moabi, myrtle, and sapele, and less often in other species.
Radiating outward from the pith to the bark of a tree are a set of "ray cells" that carry nutrients laterally through the bole. In some woods, these are very pronounced and a quartersawn board from such a tree will look very different from a flat cut board from the same tree because in the quartersawn board the surface of the board will contain significant swaths of ray cells. Oak, both red and white, are common woods that exhibit this phenomenon, but the real stunner is lacewood. Rays and ray figure are sometimes also called "buttons" or "button figure" and even more rarely as "snowflake" or "snowflake figure".
Spalting is a dark vein caused by a pattern of bacterial rot in dead wood that once stabalized often looks like a black ink line of varying thickness and great irregularity drawn through the wood. Spalting can be encouraged by keeping a dead tree moist. Spalting is a form of decay and if spalted wood isn't stabilized at the right time, it will just rot. Spalting is something that mostly happens only in softer woods. Wood that is really heavily spalted and still completely solid is rare, since advanced spalting is generally accompanied by enough decay to soften at least some areas of the wood.
Also sometimes called "crotch swirl", this figure is usually from areas near a crotch. As the name implies, the grain meanders and swirls around, often seeming to convolute and fold in upon itself. The densest portions of the swirl show up darker or shaded compared to the lighter surrounding wood. Swirl occurs in several species including walnut, mahogany, cherry and maple.
A form of "defect" or "character" (depending on how you look at it) in wood where there are numerous elongated "spots" throughout the wood where it has been eaten away by various boring agents (generally beetles). Sometimes the easten away area is filled in by some kind of natural process so that there are no voids but just discolored areas. This is usually in the form of elongated worm-shaped areas, but may also occur as spots (much like "pecky") depending on the cut of the wood and other factors.