Hardwood vs Softwood: The Real Difference, With Numbers

Hardwood and softwood are botanical categories, not hardness ratings: the USDA Forest Products Laboratory defines hardwoods as woods from angiosperms (flowering plants) and softwoods as woods from gymnosperms (mostly conifers), and the handbook opens the topic by warning that not all softwoods are soft and not all hardwoods are hard.

The confusion is old and harmless as long as you stop treating the words as a specification. If you need to know whether a board will dent, look up its side hardness. If you need to know whether it will rot on a deck, look up its heartwood decay group. The family name tells you neither.

Side hardness at 12% moisture content, from the Wood Handbook, puts the two families right on top of each other:

• Longleaf pine, softwood: 870 lbf
• Coast Douglas-fir, softwood: 710 lbf
• Quaking aspen, hardwood: 350 lbf
• American basswood, hardwood: 410 lbf
• Eastern white pine, softwood: 380 lbf
• Western redcedar, softwood: 350 lbf

So the hardest common softwood is more than twice as hard as the softest common hardwood. At the other end the gap reopens: pignut hickory reaches 2,140 lbf and sugar maple 1,450 lbf, which no commercial North American softwood approaches. The families overlap in the middle and separate at the top.

The reliable difference is under a hand lens. Hardwoods contain vessels - tube-like conduits that carry sap - so they are anatomically porous, and on an end-grain surface those vessels show as pores. Softwoods contain no vessels at all, so they are nonporous; their conduction is handled by tracheids, and a clean softwood end grain shows growth rings but no open holes.

That single fact drives a lot of downstream behaviour. Open-pored ring-porous hardwoods such as oak and ash take pigment stain deep into the earlywood ring and read as strongly striped. Diffuse-porous hardwoods such as maple have small, evenly spread pores and blotch easily with pigment stain. Softwoods have no pores to fill but have sharp earlywood-to-latewood density contrast, which is why pine stains unevenly for a different reason.

Standing in front of a living tree, the handbook's own shorthand works: in temperate regions hardwoods are typically broadleaf and, with few exceptions, deciduous, while softwoods are usually cone-bearing with needle-like or scale-like evergreen leaves.

Keep two exceptions in mind. Larches and baldcypress are softwoods that drop their needles every autumn, so a bare conifer in winter is not a contradiction. And most imported tropical woods are hardwoods whose trees never drop their leaves at all, so "evergreen" does not mean "softwood" outside the temperate zone. Our guide to identifying trees by leaf covers the rest of the field sequence.

Choose by the property the job needs, not by the family name.

• Structure and sheathing: softwood, nearly always. Southern yellow pine, Douglas-fir and spruce-pine-fir are what the span tables in the American Wood Council's deck guide are written around.
• Furniture and flooring: hardwood, because of wear. Sugar maple at 1,450 lbf and white oak at 1,360 lbf are the usual benchmarks.
• Outdoor, untreated: neither family wins. The decay-resistant list mixes both - black locust and white oak on the hardwood side, the cedars and old-growth redwood on the softwood side - while maples, birches, hickories and most pines are listed as slightly or nonresistant.
• Carving and pattern work: soft, even-textured woods like basswood at 410 lbf, regardless of family.

The quick answers people search for, each checked against the botanical rule (hardwood = angiosperm, softwood = gymnosperm) and the USDA Wood Handbook's tables.

• Pine - softwood. All pines are conifers; eastern white pine is 380 lbf side hardness, longleaf pine 870 lbf.
• Oak - hardwood. Oaks are flowering trees in the genus Quercus; northern red oak is 1,290 lbf and white oak 1,360 lbf, and their large earlywood pores make them the textbook ring-porous hardwood.
• Cedar - almost always softwood. Western redcedar, eastern redcedar, northern white-cedar, incense-cedar and Port-Orford-cedar are all conifers, and Duffield Timber notes there are only four 'true' cedars in the genus Cedrus. The exception is Spanish-cedar (Cedrela), a tropical hardwood that the handbook describes as one of the few ring-porous tropical species.
• Apple - hardwood. Apple trees flower and enclose their seeds in a fruit, which is the handbook's definition of an angiosperm.
• Yellow-poplar - hardwood, yet softer than some softwoods: Penn State Extension lists it at 2,400 N hardness against 3,100 N for loblolly pine.
• Maple, cherry, walnut, ash, hickory, birch - hardwoods.
• Fir, spruce, hemlock, larch, redwood, cypress, yew - softwoods.

A 2x4 is softwood in practice. The USDA Wood Handbook says dimension lumber is the principal stress-graded lumber in a retail yard, used mainly for joists, rafters and studs, and that yards frequently stock it in only one or two general-purpose construction woods such as pine, fir, hemlock or spruce.

Its size is a convention, not a measurement: a nominal 2x4 is 1-1/2 by 3-1/2 inches dry. Hardwood lumber is graded differently, by the clear cuttings a board yields, in grades such as FAS (Firsts and Seconds) and No. 1 Common, which is one more sign that the 2x4 aisle is a softwood aisle.

• End grain under a lens - The Wood Database recommends a 10x loupe (8x to 15x works) on a freshly cut or finely sanded end. Pores mean hardwood; no pores mean softwood. In pines, spruces, larches and Douglas-fir you may also find resin canals (Wikipedia); they are not vessels.
• Weight - heft it against a board you know. Specific gravity at 12% moisture runs from 0.31 for northern white-cedar to 0.59 for longleaf pine among softwoods, and from 0.37 for basswood to 0.88 for live oak among hardwoods, so weight alone narrows the list but does not decide it.
• Fingernail test - The Wood Database lists pressing a fingernail into the surface as a rough hardness check; a deep dent points to a soft species such as white pine, cedar or basswood, whatever its family.
• Photo - WoodLens can name the likely species from a photo of the grain; once you know the species, the family follows. Our wood grain identification page walks through the pore patterns.