Furniture Know-How: How Does Wood Become “Figured”? It’s Complicated.

To help guide our customers in their furniture choices – and unveil the art of furniture-making — we are proud to offer a blog series on the topic of wood grain and figure.

In the first blog post in this series, we described how the cutting of wood to make furniture affects the look of the grain, which contributes to the figure of a piece of wood. In the second, we took a look at how the species of wood influences its look, and how the species may affect the grain and figure. However, although some specific cuts of wood, and some specific species are prone to certain kinds of figure, the resulting look of your furniture can be hard to predict from these factors alone. So what gives your furniture its final figure exactly?

The short answer to the above question is: It’s hard to say for sure. But, of course, there’s more to it than that. For example, the “curly” figure, a highly sought after feature of Vermont wood, is prevalent in maple. It isn’t only found in maple, and it isn’t always found in maple, but it is more common there than elsewhere.

Curly Maple Tabletop by Dave Hurwitz

Dave Hurwitz describes curly maple: “If the tree grew tall and straight, the resulting grain will be straight and consistent, which makes it easier to plane flat and easier to cut. But, some tress grow in places or in conditions that cause the resulting grain to not be straight. An extreme example is curly maple. In curly maple, the grain is wavy through the length of the board. The result is that when the wavy grain is planed flat, it appears to look ruffled, or tiger striped, due to the waviness in the grain.”

Curly Maple Rocker by Kit Clark

Oddly enough, the tiger-stripe-like figure in curly maple may still feature a straight-looking grain. The wood waves perpendicular to a quarter or rift-sawn cut (see the first blog entry for a description of these cuts), so the unusual figure also runs perpendicular to the grain, but only in those cuts, just like medullary rays (also described in the first blog). Because the ends of the cell walls that are waving absorb light differently from the middle portions of the cell wall, the curly figure can also create “chatoyancy.”

Chatoyancy, an effect seen in some kinds of gems as well, isn’t figure exactly, since it’s more of an optical illusion. But, when brought out in a piece of Vermont curly maple (or other woods), it can make the waves of the figure really “pop” and is highly sought after. Because of the “differential refraction” of light, the waves appear to change in color and intensity when you move or change the lighting conditions, and can appear to dance on their own. The effect can be so striking that Hurwitz calls Vermont curly maple “our local exotic wood,” and it’s clear why.

chatoyancy

Graphical representation of chatoyancy

It’s easy enough to describe how the waving growth of the tree creates the curly figure and its resulting chatoyancy, but the question of why figure grows in one tree but not another is where we tread into murky waters. And there are many other figures natural to trees besides curly, all of which are of uncertain origin. There are plenty of theories, but as soon as they are investigated, they seem invalidated.

For example, Hurwitz says that a curly figure is more frequently found in soft maples, but it is certainly found in hard maple as well, and then takes on a whiter color. And it’s not exclusive to maple — curly figure may develop in other species, including birch and walnut. Steve Robinson, who wrote his final research paper in school on how figured wood is formed, agrees. He explains that hard maple alone can feature any number of different figures, sometimes even multiple kinds of figured wood in the same tree. In other times he would see a particular figure only in the living outer layers of tree, but not the dead inner layers. Sometimes, it would be the exact opposite.

Curly Details on a Table by Steve Robinson

In fact, in Robinson’s final paper, he concluded that there was “no evidence in the growth of figured wood,” only theories. However, some of the theories can bear some fruit. For example, he said that the tension wood in roots can reliably produce curl, but that doesn’t say much for the rest of the tree. Others, however, seem to create only trends, not explanations. Examples are the species, the climate, the geography, the soil, growth rate, tree size or age, and so on. These factors may modify a figure, or make it more likely to occur, but none of them seem to be a cause.

There are a few exceptions. “Crotch figure” for example, is created near the branching of a trunk especially in walnut and mahogany, and gives a classic look from the 18th and 19th centuries. Stumpwood is another, a particular figure frequently seen in walnut and is, as the name implies, found in the stump.

Crotch Figure in a Sideboard by Paul Zenaty, made to look like a flame

“Spalting” is the beginning stages of rot. Hurwitz explains further: “The fungus spreads through the grain of the wood, but before it has affected the structural integrity of the wood; in other words, the wood is still the same hardness and density, and hasn’t turned spongy or soft like rotted wood. Spalting can be really amazing. It can look like an abstract ink drawing of thin black lines, or it can also include areas of the wood that have changed color, to a light or dark gray, a pale orange, etc. Spalting can look really spectacular when it is book-matched, which is a process of slicing a board down the center, and then opening it up like a book, resulting in grain that is mirrored from one slice of the board to the next. It can lend a complex symmetry to an otherwise abstract piece of spalted wood.” As we mentioned in the first blog, however, this wood is dried, which kills the fungus, so furniture with a spalted figure still has good integrity and won’t continue to rot.

Spalted Maple Table Top Detail by Ray Finan

Most other figures are as much of a mystery as curly figure. We know what they are, but not why they are. Below are a few more examples for you to take a look at to help make your choices for your own furniture.

Quilted and Blister Figures: These similar figures are the result of a similar wavy undulation that occurs in curly figured wood, except the undulations occur parallel to the grain instead of perpendicular to it. Depending on the cut of wood, you’ll see either a wavy grain with a chatoyancy that makes it appear like rumpled silk, or a circular pattern that can appear like blistering or like indentations depending on the lighting.

Quilted Tabletop Detail by Dave Hurwitz

Blister Figure Detail

Birdseye Figure: Caused by localized indentations in the wood. Birdseye figure is very common in maple, much like curly figure, and so it is frequently seen in fine Vermont furniture.

Birdseye Figure Detail

Burl Figure: We wrote a two part blog series on the amazing burl (Click for Part One and Part Two). Burls are a growth on a tree believed to be caused by disease, damage or some other form of abnormal overgrowth. Whatever the cause, the grain within is a jumbled mess that results in a chaotic, but beautiful figure.

Burl Treasure Box by Pete Michelinie

 

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