Wood Grain Identification: Name a Board by Its End Grain

Wood grain identification is most reliable on the end grain, the cross-section you see when you cut a board across its length, examined with a 10x lens after a clean cut. The face of a board shows colour and figure, which vary; the end grain shows the cell pattern, which is what separates one genus from another.

The Wood Database's identification guide gives the preparation: a sharp knife or razor blade for softwoods, and for hardwoods a clean saw cut sanded through grits from about 100 up to 320 or finer. A standard magnifying glass at 2 to 4x is not enough; a 10x loupe is the tool to use. The USDA Wood Handbook says the same from the other side - examining hardwoods with a 10 to 20x hand lens greatly improves accuracy, and foresters armed with a hand lens and a sharp knife can identify lumber in the field by cutting the transverse surface.

If the piece is finished, look for an unfinished edge: the underside of a tabletop, the back of a drawer, the end of a shelf. Our wood identification topic explains the three cutting planes in more detail.

Hardwoods have vessels, which appear on the end grain as pores; softwoods do not. After that, the USDA Wood Handbook sorts hardwoods by how the pores change across one growth ring.

• Ring-porous - large earlywood pores form a ring at the start of each year, then the latewood turns dense and fibrous. The handbook's examples are hackberry, white ash, shagbark hickory and northern red oak.
• Diffuse-porous - pores stay about the same size and spacing across the ring, so the end grain looks even. Maple, birch, aspen and cottonwood, and yellow-poplar are the handbook's examples.
• Semi-ring-porous - in between; black walnut is the temperate example.

Two tropical exceptions are worth knowing because they catch people out: the handbook notes most tropical hardwoods are diffuse-porous, but teak is generally ring-porous and the Spanish-cedars semi-ring-porous. Oaks, ashes and hackberries that grow in the tropics are diffuse-porous even though their temperate relatives are ring-porous, so a diffuse-porous oak is possible in imported stock.

With no pores to read, softwoods are identified by two other features in the USDA Wood Handbook.

• Resin canals - present in pine, spruce, Douglas-fir and larch. In pine they are often visible to the naked eye on the end grain; in spruce, larch and Douglas-fir they are much smaller and need a hand lens. A softwood with no resin canals at all points away from these four.
• Earlywood to latewood transition - the handbook's figures show a gradual transition in white spruce and an abrupt one in Douglas-fir.

After that, colour, smell and weight decide. The Wood Database lists smell as a real test, noting that rosewoods are named for a rose-like odour, and mentions aromatic red cedar as the traditional closet lining.

Most identification questions come down to one of these pairs. Hardness is USDA Wood Handbook side hardness at 12% moisture; specific gravity is from the same table.

• Red oak vs white oak - both ring-porous. White oak's large pores are plugged; red oak's are open. The Knotty Lumber Co. describes a quick test: cut a small cube, dip one end in soapy water and blow through the end grain - bubbles mean red oak, while you cannot blow through white oak. See red oak and white oak.
• Hard maple vs soft maple - both diffuse-porous and pale. Sugar maple is 1,450 lbf and specific gravity 0.63; red maple 950 lbf and 0.54. Press a fingernail into an end corner: soft maple takes a dent more easily.
• White ash vs hickory - both ring-porous and pale. Shagbark hickory is heavier (0.72 against 0.60) and harder (1,880 against 1,320 lbf); a hickory board feels noticeably heavy for its size.
• Oak vs ash - oak's broad rays show on quartersawn faces as a flake pattern, which the National Wood Flooring Association calls tiger rays or butterflies on red oak; ash has no such flake.
• Black locust vs other yellow woods - The Wood Database notes that black locust glows bright yellow-green under a blacklight.
• Osage-orange - shavings soaked in water release a yellowish-brown dye, per The Wood Database. See osage-orange.

The Knotty Lumber Co. lists the three pairs above - red and white oak, hard and soft maple, ash and hickory - as the commonest mix-ups.

The USDA Wood Handbook lists colour, odour, grain pattern, density and hardness as the features lumber graders, furniture workers and hobbyists use without lab tools, and warns that accuracy depends on experience and on the specimen: atypical, decayed or small pieces are often misidentified. It is also blunt about colour: heartwood colour varies with growth history, health and genetics, and claims that a wood is exactly one colour do not hold.

Weight is more dependable. Specific gravity at 12% moisture from the handbook's Table 5-3b, lightest to heaviest:

• Eastern white pine 0.35, basswood 0.37, yellow-poplar 0.42
• Black cherry 0.50, red maple 0.54, black walnut 0.55
• White ash 0.60, northern red oak 0.63, sugar maple 0.63
• White oak 0.68, black locust 0.69, shagbark hickory 0.72

A board that feels far too heavy or too light for its apparent species is the strongest sign to look again.

Computer-vision identification is one of the primary techniques the USDA Wood Handbook lists, alongside hand-lens work, microscopy, spectroscopy and DNA methods, and the handbook's conclusion is that the best results come from applying them in a sensible sequence. For a phone photo, that means giving the software what a person with a lens would look at.

• Photograph a freshly cut or sanded end grain, square-on, in even light, filling the frame.
• Add a face-grain shot, and a quartersawn face if you have one, for rays and figure.
• Wet the surface lightly with water to bring up pores and colour, as our wood identification topic describes.

WoodLens returns the most likely species with a confidence level and shows alternative candidates when two woods are close, which is where the pair tests above help. When a result matters - an antique, a disputed sale - use a lab. The USDA Forest Products Laboratory's Wood Identification Public Service is free for private US citizens, takes up to three samples per household a year of about 1 x 3 x 6 inches, usually answers within four weeks and identifies to genus. The Wood Database also names Alden Identification Service as a paid, faster option.

Firewood is identified the same way, with one advantage: split rounds usually keep their bark. Read the bark first with our bark guide, then look at a fresh end: ring-porous oak, ash and hickory show a clear ring of pores, diffuse-porous maple and birch look even. Weight helps too - hickory and oak rounds are far heavier than poplar or pine of the same size.

Grain direction is a different question: it is about which way the fibres run, not what species the board is. Popular Woodworking's advice is to look at the grain lines on the edge of the board, which can be rising, falling, both or straight, and to plane so the cutter presses the fibres down, like stroking an animal from head to tail. It adds that this edge reading is right about 75% of the time, that spiral grain can leave a third of a board running the other way, and that interlocked grain is the hardest of all to work.

Some woods turn up in old furniture and guitars that you could not legally buy new today, which is one reason people want an ID. The USDA Wood Handbook explains the rules: the Lacey Act bans trafficking in illegally sourced plants and plant products, and CITES regulates international trade in three appendices. Appendix I covers species threatened with extinction, traded only in exceptional circumstances; Appendix II covers species whose trade must be controlled.

• Brazilian rosewood (Dalbergia nigra, also called jacaranda) is listed in CITES Appendix I, and the handbook states its international commercial trade is prohibited; IUCN lists it as vulnerable.
• Appendix II woods the handbook names include American (Honduras) mahogany from the Neotropics, Indian rosewood, the bubingas, both lignumvitae species, ramin, afrormosia and one species of macacauba. These can be traded, but with permits.

The handbook also warns that the import market keeps changing, with some species no longer available and new ones entering. If a piece might be rosewood or mahogany, an identification is the first step before selling or shipping it abroad.

The Wood Database's identification guide runs from the quickest checks to the most conclusive one:

• Is it solid wood? Rule out veneer over particleboard, laminate and printed finishes first.
• Color - natural color, not stain or weathering; sand a small spot.
• Grain - texture, figure, and whether the board is flatsawn or quartersawn.
• Weight and hardness - compare with a board you know.
• History - where the piece came from, its age and what it was used for narrow the list a lot.
• The "X-factor" - smell of fresh shavings, fluorescence under a blacklight, a water-extract color test, or a chemical spot test for known look-alike pairs.
• End grain - the most conclusive step, with a 10x loupe (the guide says anything from 8x to 15x works) on a freshly cut or sanded end.

The guide also sets expectations: identification to the exact species is not always possible, and context often decides between close relatives.

A quick way to narrow the type is how the wood was sold. Wikipedia's lumber article says North American dimensional lumber such as 2x4s, 2x6s and 4x4s comes from softwoods - pine, fir and spruce (sold together as spruce-pine-fir), cedar and hemlock - and that about 80% of lumber is softwood. A 2x4 actually measures about 1 1/2 by 3 1/2 inches after drying and planing. Hardwood lumber is sold differently: by thickness in quarters of an inch (4/4 is 1 inch, 8/4 is 2 inches) and by the board foot.

So a stamped 2x4 is almost certainly a softwood, while a 4/4 board from a hardwood dealer is where oak, maple, cherry and walnut turn up.

The Woodworkers Institute's basics guide points out that foliage and form narrow the type before you ever cut a board: deciduous or evergreen, lobed or toothed leaves, scale-like foliage in cedars. Our leaf guides cover the common trees: oak, maple, birch, black cherry and tulip poplar, plus types of cedar.