Common Name(s): Paulownia, Royal Paulownia, Princess Tree, Kiri
Scientific Name: Paulownia tomentosa
Distribution: Native to eastern Asia; also planted in eastern North America
Tree Size: 30-65 ft (10-20 m) tall, 2-4 ft (.6-1.2 m) trunk diameter
Average Dried Weight: 18 lbs/ft3 (280 kg/m3)
Specific Gravity (Basic, 12% MC): .25, .28
Janka Hardness: 300 lbf (1,330 N)
Modulus of Rupture: 5,480 lbf/in2 (37.8 MPa)
Elastic Modulus: 635,000 lbf/in2 (4.38 GPa)
Crushing Strength: 3,010 lbf/in2 (20.7 MPa)
Shrinkage: Radial: 2.4%, Tangential: 3.9%, Volumetric: 6.4%, T/R Ratio: 1.6
Color/Appearance: Heartwood typically a pale grayish brown, sometimes with a reddish or purplish hue. Pale white sapwood not clearly demarcated from heartwood. Overall appearance (both the wood and the tree itself) is not too unlike Catalpa, another lightweight and porous hardwood.
Grain/Texture: Grain is generally straight, with a coarse, uneven texture. Very large pores give Paulownia a striped, porous look.
Endgrain: Ring-porous, occasionally semi-ring-porous; 3-5 rows of very large earlywood pores, medium to small latewood pores; tyloses common; growth rings distinct; rays visible without lens; parenchyma aliform (winged and lozenge), confluent, and banded.
Rot Resistance: Reported to be durable regarding decay resistance, with decent weathering characteristics, though susceptible to insect attack.
Workability: Given its straight grain and light weight, Paulownia is extremely easy to work. However, due to a high silica content in some trees, the wood can have a strong blunting effect on cutting edges. Takes a wide variety of glues, stains, and finishes well.
Odor: No characteristic odor.
Pricing/Availability: Paulownia is seldom offered for sale in the United States, though it’s actually grown on plantations and exported to Japan, where demand for the wood is much higher. Prices are likely to be high for a domestic species.
Sustainability: This wood species is not listed in the CITES Appendices or on the IUCN Red List of Threatened Species.
Common Uses: Plywood, veneer, furniture, boxes, millwork/siding, musical instruments (electric guitar bodies), clogs, carvings, and other small specialty items.
Comments: The other Balsa. Paulownia is used in applications where a lightweight (yet proportionately strong) wood is needed. It’s widely used in Japan for construction of the koto (a stringed musical instrument), as well as other household items, where the wood is referred to as Kiri. Paulownia is one of the fastest growing trees in the world, capable of growth rates of well over seven feet per year as a seedling! But while it’s highly appreciated and cultivated in Asia, Paulownia has come to be considered an invasive species in the United States.
Paulownia was named after Queen Anna Pavlovna of Russia (1795-1865), and is sometimes called Royal Paulownia or Princess Tree.
Scans/Pictures: A special thanks to Mike Leigher for providing the wood sample of this wood species.