Rock Elm (Ulmus thomasii)

Rock Elm (Ulmus thomasii)

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Common Name(s): Rock Elm, Cork Elm

Scientific Name: Ulmus thomasii

Distribution: Midwestern United States

Tree Size: 65-100 ft (20-30 m) tall, 2-4 ft (.6-1.2 m) trunk diameter

Average Dried Weight: 47 lbs/ft3 (755 kg/m3)

Specific Gravity (Basic, 12% MC): .57, .75

Janka Hardness: 1,320 lbf (5,870 N)

Modulus of Rupture: 14,800 lbf/in2 (102.1 MPa)

Elastic Modulus: 1,540,000 lbf/in2 (10.62 GPa)

Crushing Strength: 7,050 lbf/in2 (48.6 MPa)

Shrinkage: Radial: 4.8%, Tangential: 8.1%, Volumetric: 14.9%, T/R Ratio: 1.7

Color/Appearance: Heartwood is light to medium reddish brown. Paler sapwood is usually well defined.

Grain/Texture: Grain is interlocked (making it very resistant to splitting). With a somewhat coarse, uneven texture.

Rot Resistance: Rated as non-durable; susceptible to insect attack. Living trees are susceptible to Dutch elm disease.

Workability: Can be a challenge to work because of interlocked grain, especially on quartersawn surfaces. Planing can cause tearout and/or fuzzy surfaces. Poor dimensional stability. Glues, stains, and finishes well. Responds well to steam bending, and holds nails and screws well.

Odor: Elm usually has a strong, unpleasant smell when green; though once dried has very little odor.

Allergies/Toxicity: Although severe reactions are quite uncommon, Elm in the Ulmus genus has been reported as a sensitizer. Usually most common reactions simply include eye and skin irritation. See the articles Wood Allergies and Toxicity and Wood Dust Safety for more information.

Pricing/Availability: Should be moderately priced, though availability from mature trees has been greatly diminished by Dutch elm disease.

Sustainability: This wood species is not listed in the CITES Appendices or on the IUCN Red List of Threatened Species.

Common Uses: Boxes, baskets, furniture, hockey sticks, veneer, wood pulp, and papermaking.

Comments: Elm trees are commonly infected with Dutch elm disease, a fungal disease spread by elm bark beetles. D.E.D. has wiped out millions of Elm trees worldwide.

Related Species:

Related Articles:

Scans/Pictures:

Rock Elm (Ulmus thomasii)

Rock Elm (sanded)

Rock Elm (sealed)

Rock Elm (sealed)

Rock Elm (endgrain)

Rock Elm (endgrain)

Rock Elm (endgrain 10x)

Rock Elm (endgrain 10x)