Basswood.

The behavior of basswood under the special treatments encountered in plywood manufacture make it an especially desirable material for cores and cross-bandings. It is soft textured, straight grained, easily worked, and easily glued. Basswood veneer is made almost entirely by the rotary process, and as plywood panels finds such uses as drawer bottoms and mirror backings. Basswood panels are also excellent for jig-sawing and for the type of work done in manual training schools. The wood is white and presents an excellent surface for painting.

Magnolia.

The wood of magnolia resembles in texture that of yellow poplar, although it is somewhat heavier and harder. Magnolia is compact in structure and moderately easy to work. Its color generally runs from creamy white to light brown. It has a satiny luster and is an excellent base for paint.

Cottonwood.

This hardwood is used by the plywood industry for special utility rather than for decorative purposes. A great deal of cottonwood is manufactured into plywood for boxes and crates, for furniture linings, as drawer bottoms, for kitchen cabinets, and even for musical instruments.

Cottonwood is light in weight, has a uniform texture, and does not split easily. It is grayish white, with indistinct annual rings and fine grain. It is easy to glue, works easily with tools, and holds paint well.

Sycamore.

Although the use of sycamore in plywood manufacture has been diverted principally to the production of utility veneers, a greater appreciation of its attractive figure has developed and its use in decorative panels is becoming pronounced. Sycamore, when cut on the quarter, shows a handsome "flaky" figure. The sapwood is lightcolored, but with a distinct reddish or pink cast. The heartwood is darker, being of a reddish brown. Sycamore is close-textured and is moderately heavy, hard, and strong. It has interlocked grain, and is therefore difficult to split.

Elm.

The uses for elm in the woodwork and furniture fields have broadened in recent years. Somewhat similar in general appearance on flat-cut surfaces to oak, ash, or chestnut, elm takes a fine polish. The heartwood is light brown, usually with a reddish tinge, while the sapwood is almost white. Elm is moderately heavy, tough, and straight-grained, and holds fastenings well.

Chestnut.

The wood of chestnut is ideal for lumber cores of hardwood plywood and is much used for this purpose. It is in the group of woods most easily glued and is easy to work. It can be readily kiln-dried or air-seasoned and dries flat, with little tendency to warp, split, or honeycomb. In resistance to decay, chestnut is classed among the most durable woods. Unfortunately, chestnut has been severely at

tacked by a blight that has already killed great numbers of standing trees and threatens its extinction" in the United States. Since the blight in no way subtracts from the quality of the wood, lumbermen have been able to utilize closely the affected trees.

noticeable.

Figure 7.-Flush plywood paneling. By careful installation, joints can be made scarcely Other Woods.

Numerous other American species finding occasional use in the hardwood-plywood industry round out a group of woods which range in cost from the lowest priced to the most costly, and in color from light cream to deepest brown. Among woods not described in the preceding sections are ash, aspen, beech, alder, cherry, butternut, hackberry, locust, buckeye, holly, pecan, hickory, apple, and others.

FOREIGN HARDWOODS

Although American hardwood-plywood mills are devoted largely to working native woods, the domestic supply of hardwood faces is supplemented by imports from Africa, Asia, Australia, Central and

Figure 8.-The hardwood paneling in this room not only frames the fireplace, but is a supplementary frame for the oil painting.

South America, and Europe, usually in the form of logs for cutting into veneer. Of the total production of face veneer, according to census reports for 1937, about one-third was produced from foreign woods. Such veneers are usually superimposed on cores and crossbanding of domestic hardwoods, so that practically all American hardwood panels represent up to 90 percent native material.

The following paragraphs present brief descriptions of the more important foreign woods utilized by manufacturers of hardwood plywoods.

Mahogany.

The excellent reputation which mahogany has attained through centuries of use in all parts of the world is based on a fortunate combination of properties essential to a first-class cabinet wood. Chief among these properties which mahogany possesses to a high degree are attractive appearance, ease of working with tools, fine finishing qualities, and ability to "stay in place."

Figure 9.-Modern piano, compact in design, exemplifying use of choice hardwood plywood.

Mahogany is produced principally from two species of the genus Swietenia, growing in the West Indies, Mexico, Central America, and northern South America (the upper Amazon in western Brazil and in Peru). The wood is frequently sold under source designations indicating its origin, such as Honduras mahogany, Mexican mahogany. To these species of the genus Swietenia the term "genuine mahogany" is often applied, to distinguish it from other woods sometimes referred to in the trade as "mahogany," but which are not from a species of this genus.

Mahogany has long been the principal imported veneer wood. According to trade statistics, it accounted for 25 percent of all American face veneers produced in 1939. The beauty of mahogany veneers in both figure and color is their outstanding selling point. Practically all the figures found in various other woods as a result of irregular grain, are obtainable from mahogany. The characteristic interlocking of the fibers of the wood gives a ribbon or stripe figure

to quarter-sawn material. Mottled, fiddleback, raindrop, roe, and curly figures are also present occasionally. Crotches in the tree trunk produce a very attractive figure, and distorted growth yields effects, such as blister figure and burl. Plain-cut mahogany usually has a figure of soft outline and low contrast, although occasionally it shows distinct undulations of the grain. The color of the heartwood varies from very pale to a very dark reddish brown, which grows richer and darker with age. The sapwood seldom appears in

veneers.

Mahogany plywood is widely used in both traditional and modern styles of furniture, and for wall paneling, radios, pianos, and other musical instruments. For traditional styles, the so-called Old World type of finishes predominates. These finishes, closely approximating the appearance of fine old museum pieces, are a great improvements over the lifeless, heavily stained surfaces of a few years ago. For modern designs, the lighter finishes are preferred. These tones, obtained by the use of bleaches, range from the light reddish browns to honey tones.

African mahogany is produced from the genus Khaya, principally from the species ivorensis. It belongs to the mahogany family (the Meliaceae) and is known in American trade only as "African mahogany." The wood of khaya, or "African mahogany," has, on the average, a lighter color than the mahogany of the genus Swietenia and less tendency to darken with age. When cut on the quarter it shows a similar, but more strongly defined, ribbon grain. Its chief advantages are that it runs more to figured wood and can be obtained in large sizes. This wood is employed for practically all the purposes to which mahogany is put, and is of particular value in the fabrication of large panels. "African mahogany" is imported in considerable quantities, accounting for about 75 percent of the mahogany face veneers produced in the United States.

"Philippine mahogany" sold commercially includes about six species belonging to several genera, practically all of which belong to the dipterocarp family (Dipterocarpaceae) native to the Philippine Islands. These woods, although coarser in texture, resemble mahogany in general appearance and compare favorably in weight and strength properties. The various woods range in color from a pale pinkish yellow to a dark reddish brown. They are often classified commercially according to color into two groups-the red lauans, or "dark-red Philippine mahogany," and the white lauans, or "light-red Philippine mahogany." Of the first group, tanguile and red lauan comprise about 95 percent. In the second group, white lauan, almon, and bagtican are the most important trees. Many buyers specify these woods by their respective names to prevent misunderstanding.

The individual lauan species, or "Philippine mahoganies," show considerable resemblance to each other in their physical and mechanical properties; they differ principally in range of color, as mentioned in the preceding paragraph. Because of interlocked grain, these woods generally show on the quartered surface a ribbon figure consisting of alternate light and dark stripes, which are usually much more strongly defined than those in mahogany and result in a more pronounced figure. Of all the commercially important lauans, tanguile bears the closest resemblance to mahogany. The interlocked