Woodsense: Spotlight on BirchComments (0)
This article is from Issue 52 of Woodcraft Magazine.
North America’s do-it-all lumber
Technical Consultant: Larry Osborn
The commercially important birch species found in North America are but a few of the 50 types of birch found around the world–from Japan to Scandinavia to Russia. The native birches most used by the U.S. and Canadian forest products industry are yellow birch (Betula alleghaniensis), sweet birch (B. lenta), and paper birch (B. papyrifera). Of lesser importance are river birch (B. nigra), gray birch (B. populifolia), and western paper birch (B. papyrifera variety commutata).
Although somewhat similar in appearance and grain texture, the wood of yellow and sweet birch tends to be heavy, hard, and strong, with good shock resistance while that of paper birch weighs less, and is softer and not as strong.
Throughout history, the domestic birch family of hardwoods has made countless contributions to Native Americans, European explorers, early settlers, trappers, pioneers, and present-day populations of the United States and Canada.
History in woodworking
Native Americans looked to the paper birch’s bark for the sheathing of dwellings and canoes. From the tree’s sap came sweet syrup. Its young twigs provided medicine (the salicylic acid in them was the precursor to aspirin). The bark of black birch proved to be a tough, enduring material for woven baskets.
Early woodworkers used yellow birch for cooperage, wagon hubs, cabinets, chairs, and desks. In the 1950s, popular blonde “Scandinavian” furniture was built from it.
Today, most yellow birch becomes boxes, cabinets, cooperage, furniture, woodenware, interior trim, flooring, doors, and millwork. The wood is also joining ash and maple as stock for baseball bats. As plywood, yellow birch serves as flush doors, TV cabinets, and office furniture. Despite changes in taste and fashion, birch has been in demand for furniture and cabinetry for almost a century.
You’ll find paper birch the common material for turned products such as Shaker pegs, dowels, and buttons. It also shows up in wooden toys, matchsticks, toothpicks–even chopsticks!
Where the wood comes from
The largest domestic source of birch lumber and veneer is the yellow and sweet birch that principally grows in the Northeastern and Great Lakes states. While you’ll find paper birch in abundance in the same range, it’s not usually available as lumber. Yellow and sweet birch (frequently mixed and marketed together) are also found in the Appalachian Mountains as far south as northern Georgia.
What you’ll pay
Due to its availability as lumber and plywood, yellow birch and sweet birch will be the focus here. FAS boards in 4/4 thickness usually cost less than $5 per board foot, with Select and Better (S&B) running about 50 cents less per unit. Figured birch can reach $8 and up per board foot.
The utility A-2 grade, 3⁄4" birch plywood runs about $70 per 4×8' sheet at home centers. The higher face grade AA costs more; lesser faces, such as B and C, cost less. Most lumber outlets carry thinner stock, too, for use as panels in frame-and-panel cabinet doors. Baltic and Finnish birch plywoods are made in Europe of extra-thin (1⁄16") thickness of void-free alder and birch plies for the core and top-notch birch veneers for the faces. The Finnish variety utilizes exterior adhesive for outdoor use. Neither of these are available in 4×8' sheets, but rather 60×60" sheets and in thicknesses from 4mm (1⁄8") to 18mm (3⁄4") in approximately 1⁄4" increments. Apple-ply is the American-made version. It comes in 4×8' and smaller panels and standard thicknesses (1⁄4"-1 1⁄2").
How to select the best stock
Only specialty wood suppliers or lumber outlets offer yellow birch lumber. Birch hardwood plywood, however, is more widely available, although not all retail outlets will carry a wide selection of grades and thicknesses.
Normally, yellow birch has a light yellow to nearly white narrow band of sapwood. The heartwood ranges from cream to tan to reddish tan, and may even have tinges of gray or red. For projects, choose boards for color uniformity, avoiding those with both heartwood and sapwood as these can cause problems when color-matching. Because commercial demand for light-colored wood is so strong, birch, like maple, is often graded and sold by its color (“sap” or “white”), meaning you’ll pay a premium for color-selected stock. Note, too, that yellow birch from the northern part of its growing range will be heavier and contain a finer grain than wood from the southern region.
Birch plywood can also be graded and sold by its color, just like birch. The highest grade is white, followed by uniform light, and natural. Lower paint and shop grades cost less. At a home center, the mid-level grade stock will vary widely in appearance from sheet to sheet, and contain minor natural defects, varying amounts of heartwood and slightly less uniform core material. If you’re able to sort through the stack for the best-looking sheets, you’ll save some money compared to buying the top white grades at a hardwood lumberyard.
It’s a fact that…
The enormous flying boat nicknamed “The Spruce Goose” built by Hughes Aircraft of California in the mid-1940s wasn’t really made of spruce. Due to its strength-to-weight ratio, North American yellow birch was the primary wood in its construction. Solid stock became wing and fuselage framing and veneer was laid up in laminations for all skin surfaces except those for control (ailerons, rudder, etc.), which were fabric covered. The giant seaplane had a 320' wingspan and weighed 400,000 pounds. It flew only once— over a mile 70' above Long Beach harbor on November 2, 1947.
Working yellow birch in the shop
Because yellow birch is nearly as hard as sugar maple, it dulls cutters, so if you don’t presently use carbide-tipped blades and cutters work, start now. Compared to maple, yellow birch machines better, because it doesn’t tear-out during edge jointing, or burn as easily. Due to its hardness, yellow birch should be fed at a moderate rate when ripping to give the blade time to clear sawdust.
As we said, yellow birch’s fine texture and generally straight grain translates to machining well and routing beautifully, but boards with wavy figure mean taking lighter cuts. Plane the wood at a slight angle to avoid surface chipping.
This wood will work with all adhesives, but its closed-pore density requires glue with a long open time to allow some surface penetration. Also, be sure to pre-drill for screws as the wood readily splits. Though hard, birch sands easily, and it turns like a dream.
Deciding on the right finish
Yellow birch takes all clear finishes equally well, and holds paint nicely. For even staining, though, you’ll first need a wood conditioner or two sealer coats before staining to reduce blotching. Dye stains are a better choice. The wood’s close grain doesn’t require filling.
Because yellow birch’s grain closely resembles cherry, mahogany, and walnut, you can transform it with by stain as furniture and cabinet manufacturers have done for decades.
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