Janka Hardness is defined as a measure of the hardness of the wood produced by a variation on the Brinell hardness test. The test measures the force required to push a steel ball with a diameter of 11.28 millimeters (0.444 inches) into the wood to a depth of half the ball’s diameter.
The results are stated in various ways in different countries, which can lead to confusion, especially since the name of the actual units employed is often not attached. In the United States, the measurement is in ft. pounds-force. The most common use of Janka hardness ratings is to determine whether a species is suitable for use as flooring.
The higher the number, the harder the species is.
Cumaru (Dipteryx odorata)
Source: S. America
Heartwood: reddish brown with yellowish brown streaks
Janka hardness ratings: 3,540
Cumaru is another dense, durable timber species characterized by a tightly interlocked grain and yellowish-brown streaks. Cumaru is in many respects similar in appearance to Ipe but without the greenish olive undertone.
Cambara (Erisma uncinatum)
Source: S. America
Heartwood: red/purple brown
Cambara has a lower density than other popular decking; however, with the correct kiln drying, its hardness is similar to our other species. While not as durable as species such as Ipe, it has nevertheless gained considerable popularity as an elegant decking timber due to its consistent color and straight grain. Cambara is available in many countries. In Bolivia, it is harvested from forests managed and operated under forest management procedures laid down by the FSC and the Bolivian government organization SIF.
Ipe (Tabebuia spp.) — “Ironwood”
Source: S. America
Wood color: olive brown to brown
Janka hardness ratings: 3,680
Ipe is widely recognized as one of the hardest, most robust, and most durable timber species in the world. Because of its density, it has a high fire resistance rating. It is a very stable timber in outdoor exposure, so it is used widely for decking and other outdoor structures where strength and durability are essential. Ipe is available from Bolivia, Brazil, Paraguay, and several other South American countries. Forests are managed and operated under forest management procedures laid down by both the FSC & government organizations in the respective countries. Example: IBAMA in Brazil.
Tigerwood (Goncalo Alves)
Source: S. America
Wood color: reddish brown with wide dark stripes
Janka hardness ratings: 2,160
Harvested in Brazil, Tigerwood has a reddish brown color with wide dark brownish black “tiger” striping. It is a tight-grained, very durable wood. It is 70% harder than Red Oak (Janka:2160). It makes a beautiful, unique deck with striking contrast striping, which tends to mellow with age.