Northern White Cedar — Density, Movement, Workability & Cost

Traditional canoe builders bend northern white cedar (Thuja occidentalis) ribs green, straight over a form, and the wood cooperates because it's lighter and softer than every other species this site tracks — a fingernail will genuinely mark it, and a fully rigged set of ribs is light enough to carry under one arm.

The lightest, softest wood in this dataset

At 22 lb/ft³ and 320 lbf on the Janka scale, northern white cedar — also called arborvitae or swamp cedar — is softer and lighter than any other species this site covers, domestic or imported. Knots are frequent and, in contrast to the surrounding soft material, genuinely hard, which means they'll deflect a plane iron unexpectedly if you're not braced for the sudden change in resistance.

Modest movement that suits both canoes and shingles

Tangential shrinkage of 4.9% against a radial figure of 2.2% gives a 2.2 ratio, over this site's movement-prone threshold in relative terms, but the tiny absolute numbers keep real-world movement minor. A 6"-wide board seasoning from a wet 14% down to a drier 8% loses about 0.059" (1.5mm) across its width; the wood movement calculator handles other widths. A thin 1/4"-thick, 4"-wide, 6-foot canoe planking strip weighs less than a pound — about 0.92 lb — per the wood weight calculator.

Gluing greedy end grain, and living with the softness

The very low density means end grain absorbs glue eagerly, sometimes greedily enough that a joint can starve if you don't apply extra adhesive or a sizing coat first. Boatbuilders value this species specifically for planking, since it holds a fastening — a copper tack, a screw — without splitting, despite how soft it is, a genuinely useful combination that a harder, more brittle wood wouldn't offer in the same way.

Durability, cost, and its historical role before pressure treatment

The heartwood is very durable — this was the standard North American shingle and fence-post wood for generations before pressure-treated lumber existed, and the reputation is earned rather than nostalgic. At roughly $6 per board foot it's priced in this site's moderate tier. Canoe ribs and planking, shingles, fence posts, saunas, and log cabins round out its uses — the sauna use, like western redcedar's, trades on genuine rot resistance combined with a pleasant scent and low thermal mass.

Choosing it deliberately over a tougher cedar

Against western redcedar, northern white cedar is considerably lighter and softer, which makes it the better choice specifically for canoe ribs and other applications where bending green and minimizing weight both matter — western redcedar's greater toughness makes it the better general-purpose exterior building material where the two overlap in use.

What people actually ask about northern white cedar

Is northern white cedar the same tree as arborvitae grown as an ornamental hedge? Yes — arborvitae is simply the common ornamental name for the same species, and hedge-grown trees are rarely large enough to yield usable lumber, so timber-grade material comes from forest-grown trees instead.

Why does canoe-rib cedar need to be bent green rather than dried first? Green wood is far more flexible and less prone to cracking under the tight bending radius a canoe rib requires; drying first would make the wood too brittle to bend into that shape without breaking.

Is northern white cedar strong enough for structural framing, given how soft it is? It's traditionally used for log cabin construction and similar structural roles despite its softness, since its strength-to-weight ratio and rot resistance both work in its favour, though a builder should still size members generously compared to a denser structural softwood.

Why do the knots in northern white cedar feel so much harder than the surrounding wood? Knots form from denser branch tissue that resists compression and cutting far more than the soft, low-density surrounding wood, so the contrast feels more extreme on this species than it would on a naturally denser softwood where the base material is already closer to the knot's hardness.

Northern white cedar's other common name, arborvitae — Latin for "tree of life" — dates to French explorers reportedly cured of scurvy with a tea brewed from its vitamin-C-rich foliage. At 22 lb/ft3 and 320 lbf it's also the lightest and softest species in this dataset. (The figures above blend two sources: FPL's Table 4-3 for shrinkage, The Wood Database's 12%-moisture-content testing for density and Janka hardness.)