Empress Lumber

Common Names: Paulownia, Empress, Kiri

The Empress, a member of the Paulownia family, is recorded in the Guinness Book of World Records as “officially amazing.” Reaching up to 20 feet tall in its first year, it is the fastest growing tree in the world. Within 10 years, the Empress will reach maturity and can be harvested for lumber.

It produces an exotic hardwood that is pale brown or blonde, sometimes with a reddish or purplish hue. It exhibits excellent rot resistance and good weathering characteristics. It  is straight-grained, and silky to the touch, light weight and extremely easy to work making it a great choice for your next project.

Heartwood typically a pale brown, sometimes with reddish or purplish hue. Pale white sapwood not clearly demarcated from heartwood.

Rot Resistance
Reported to be durable regarding decay resistance and decent weathering characteristics.

Given its straight grain adn light weight, Paulownia is extremely easy to work and takes a wide variety of glues, stains and finishes well.

No characteristic odor.

Lumber Properties

• Nearly 1/3 the weight of Oak (44 lbs p/cubic ft) and half the weight of Pine (30 lbs p/cubic ft).

• It has one of the highest strength to weight ratios of any wood.

• All normal finishing materials can be applied and it bonds well with glue.

• It is highly durable and resists decay under non-ground contact conditions.

Technical Specifications

Density @ 10% moisture content: 14.37 – 18.75 lbs/cuft
Density @ 10% moisture content: 18.17 lbs/cuft
Density @ 10% oven dried: 17.11 lbs/cuft

Chemical Composition
Alpha-Cellulose content: 40.72%; 38.50%-41.46%
Pentosan: 24.78%: 20.56%-25.35%
Lignin content: 20.87%; 21.24%-24.28%
Leaves: ursolic acid, C30H4803; matteucinol, C18H1805
Xylem: Paulownium, C20H1807@CH30H; d-Sesamin
Bark: syringin, C17H2409@H2O; Catapinoside

Bending & Compression Properties
Modulus of rupture (mor): 5420-5740 psi
Modulus of elasticity (moe) x10 to 6th: 0.735-0.758 psi
Compression parallel to grain: 2800-3560 psi
Compression perpendicular to grain: 300-440 psi
Shear parallel to grain: 800-1150 psi

BTU (British Thermal Unit)
7600-8400 per pount

Janka Hardness Scale: 260-290

Shrinkage Coefficient (%)
Specific gravity: 0.251 – 0.274 (23 to 30% of the density of water)
Specific gravity @ 10% MC: 0.265
Radial: 1.1 – 2.7
Tangential: 2.1 – 4.9
Green to Oven Dry: 5.9

Moisture Absorption
(92% Relative Humitidy @ 20 degrees C)
1-day; 2-day; maximium
12%; 15%; 19%