tion of the cut is against the annual rings of the wood. A considerably enhanced striped figure is thus produced. This method of cutting increases the yield of heartwood, which in some instances is desirable. The sapwood of some woods-for example, walnut-is usually much lighter in color than the heartwood. (See fig. 13.) Flat Slicing.

Logs to be sliced are sawn into flitches, stripped of their bark, and placed in large vats, where they are steamed. When sufficiently soft, they are further trimmed and then taken to the cutting machine, where a single flitch is fixed horizontally in a heavy movable frame. The frame brings the flitch down against the cutting edge of a long, stationary knife, which shaves off veneers of the desired thickness, ranging from 1/100 to 120 inch. The standard American thickness for face veneers is 28 inch. Slicers are capable of cutting veneer logs 16 feet in length.

TH

(A)

(B)

Figure 13.-Two methods of cutting. (A) Half-round rotary cutting. In this method, the heart side of the flitch is attached to the stay log and the direction of cut is with that of the annual rings. (B) Back cutting on rotary. In back cutting, the bark side of the flitch is attached to the stay log. The first sheets are cut from the heart side and opposite to the direction of the annual rings. This method of cutting enhances the stripe-figure effect.

Quarter Slicing.

In this, the most expensive of all veneer knife-cutting methods, the actual cutting is performed exactly as in flat slicing; the difference is in the preparation of the log, which is sawn into quarter-cut flitches. The veneer is cut approximately at right angles to the annual rings, producing straight stripes running the entire length of the veneer in most woods. In woods having prominent rays, this method also produces a flake figure.

Sawing.

Sawing is the oldest method of veneer cutting. The log or flitch is not conditioned but is mounted on a traveling carriage which trundles it back and forth against the blade of a saw, cutting it through from end to end. This method is extravagant, since the saw kerf is sometimes about the same thickness as the veneer which is cut. This method is used mainly for veneers which are comparatively thick or unusually hard or are otherwise difficult to handle properly when cut with a knife. Quarter-sawn veneers are produced from quartercut flitches. Sawing is generally used for white oak veneers and for stock veneers for such purposes as mahogany doors and maple grandpiano rims,

Face veneers, as they come from the machines, are carefully kept in their original order, are dried to the required moisture content, clipped, sampled, and placed into crates, and then stored for shipment. Veneers are often cut to specifications on order.

HOW FIGURED VENEERS ARE OBTAINED?

Few persons have a clear conception as to why wood is beautiful. Some think it is the way the wood grows, others that it is the way it is cut, and still others believe it is the way it is finished. Finish may bring out and intensify the beauty of figure; otherwise, finishing principally seals the wood or changes the color. Actually, the real beauty of wood is due to its figure, which is the result of the way a tree grows and the way it is cut. The preceding section describes briefly the basic methods of cutting.

Figure in wood is the pattern formed by the (1) the annual growth rings, (2) the medullary rays, (3) pigment figure (irregular infiltrations of coloring matter), and (4) irregularities of growth, such as cross grain, wavy grain, burls, knots, or various other distortions of the normal course of the fibers. It is obvious that in many instances figure may result from a combination of these four basic factors.

Annual Growth Rings.

Growth occurs in what is commonly known as the cambium, which is a thin layer of growth tissue between the bark and wood. Each year, by growth in the cambium, a tree adds a layer of wood on the outside of that previously formed, thereby increasing the diameter of the trunk and pushing the bark outward.

If growth is interrupted each year, by cold weather or dry seasons, the character of the cells at the end of each year's growth and the beginning of the next differs sufficiently to define sharply the annual layers or growth rings. In parts of the Tropics, where tree growth is continuous throughout the year, no well-defined annual growth layers are formed.

In many species of trees each year's growth is divided into two layers, refered to as springwood and summerwood. The springwood is usually composed of large, thin-walled cells, while the summerwood cells are smaller and are usually thick-walled. In hardwoods (broad-leaved trees, which are usually deciduous) are found pores or ducts. In a number of species of hardwoods, such as chestnut or ash, these vessels are much larger in the springwood than in the summerwood, and such woods are known as ring porous; other hardwoods are known as diffuse porous. Softwoods (coniferous needleleaved trees) are nonporous. Thus, the various species of trees produce a wide variety of cell structure, size, and arrangement in each annual growth ring, which in turn produces variable figures or patterns when cut into lumber or veneer.

The pattern formed by annual growth rings consists of stripes on quarter-sawed surfaces and of stripes, parabolas, and ellipses on plain-cut surfaces. Growth-ring figure is quite pronounced in oak, ash, chestnut, and elm, and moderately so in black walnut, butternut, birch, and pecan.

7 This section is based in part upon Why Wood Is Beautiful, by George N. Lamb, reprinted from American Forests.

veneer.

Medullary Rays.

While growth cells in most trees are elongated parallel to the axis of the tree, certain species, particularly such hardwoods as white oak and beech, produce cell aggregates aligned at right angles to the axis. These groups of radial cells (known as medullary rays-or, more often, merely as wood rays) produce a flake figure such as is characteristic in quarter-cut white oak. Other well-known woods disclosing a prominent flake or fleck figure when cut on the quarter are lacewood and sycamore.

Pigment Figure.

Uneven distribution of color or pigment is the principal cause of figure in some woods and also frequently accentuates the figure that is due to other causes. The commonest color variation is the difference in the color of the heartwood and the sapwood. In such species as walnut, orientalwood, gum, and yellow birch, the heartwood is much darker than the sapwood. When both heartwood and sapwood appear in matched sheets, a pattern results. If this pattern is pleasing, it is retained; if it is not pleasing, the light wood is stained to match the heartwood.

In other trees, such as rosewood, zebrawood, and Macassar ebony, the heartwood seems to have darkened only in concentric zones. When such woods are quartered, a stripe figure results. When flat cut, the figure is wild on account of the alternate color zones. Color, sometimes desirable, may also be due to stains from decay or to incipient decay itself.

Irregularities of Growth.

Crooked or bulged logs, burls, crotches, or other distortion of the normal course of the fiber growth produces figures of peculiar or fantastic shape. Irregular grain is undoubtedly the most important factor in the production of figure in wood. Some of the most outstanding of these irregularities are:

Crotch-Where a tree forks into two limbs, the crushing and twisting of the fibers between the two limbs as they increase in girth makes one of the most striking figures to be found in wood. There is no sharp line of demarcation between crotch and swirl figure. The swirl figure comes from the outside of the crotch block, and the true crotch figure from the center part.

Swirl.--Swirl figure proper comes from the outer sides of the block that produces the crotch figure. Therefore, it is a matter of opinion where the swirl figure ends and the crotch figure begins. Also, the sheets from the extreme outside of a crotch block may yield a very plain swirl, while nearer the center the swirl may be highly figured as it approaches the crotch pattern.

In addition to swirls from crotch blocks, a twisted, crooked, or limby log may, when flat cut, produce a plain swirly figure, or, if the log is also figured, it may produce a figured swirl. In the smaller panels it is often impossible to tell whether the swirly figure came from a crotch or from a swirly log. From the standpoint of general appearance, figured flat-cut mahogany also belongs in this group.

Stump (or butt).-At the base of the trees of some species, such as walnut, the wood becomes wrinkled from lack of room for new growth and perhaps from the swaying of the tree. If a tree is "swell butted," the chance is that the "stump figure" is more pronounced.

satinwood).