Names and distribution:
Kiri, also known as the bluebell tree, originates from Asia. This type of wood is naturally widespread in Japan and China. Kiri is also being planted more and more frequently in domestic parks because of its expressive flowers and strikingly large leaves that are reminiscent of rhubarb. Recently, there are also plantations in DE, ES and Eastern Europe that will produce usable trunk diameters in a few years. Botanically, kiri belongs to the genus Paulownia, which belongs to the labiate family.
Wooden picture:
The heartwood is yellowish to pale gray, coarse-pored with clearly separated growth zones. Mostly straight grain, overall less decorative.
Properties:
The spec. weight is approx. 0.26-0.30 t/cbm at a wood moisture content of 10%. The swelling and shrinkage values are given as radial 2.4% and 3.9% tangentially. Drying is unproblematic, but should still be carried out carefully with thick cross-sections. Can be worked very well in all directions despite silicate inclusions. Smooth surfaces are produced, although they are sensitive to pressure due to their low hardness. The bending stiffness is extraordinarily high despite the low weight. In relation to hickory, the ratio of bending strength to raw density is approximately the same. The wood is classified as flame-retardant, which is likely to be important for structural applications.
Use:
Construction wood (“tiny-houses”), used as a lightweight construction board, for surfboards, electric guitars and basses, furniture (Japan) and ski cores
Reference:
Wood information service leaflet series
GOTTWALD (1970) Wood identification of the most important commercial timbers
WAGENFÜHR (1996) Wood atlas
