If you are particularly concerned about hygiene, a cutting board made of Aomori Hiba is a worthy choice. Aomori Hiba contains Hinokitiol (Thujaplicin), which possesses antibacterial properties, making it resistant to bacteria and mold growth. Plants produce various chemicals to defend themselves against attacks by bacteria, molds, and insects, and Hinokitiol is one of them.
Hinokitiol was discovered in 1936 by Dr. Tetsuo Nogami from the essential oil components of Taiwanese Hinoki. It is effective not only against bacteria but also against fungi. Moreover, it has been reported to have effects on numerous non-pathogenic bacteria, in addition to pathogenic bacteria such as E. coli.
Aomori Hiba is lethal to certain types of insects. The Japan Anti-Termite Association conducted laboratory testing in April 1981. One hundred termites were placed in a container with sawdust from Aomori Hiba wood, which had been cut 61 years ago. The observation revealed that all of them became inactive within 24 hours and deceased within 240 hours (10 days).
Hiba wood inherently has a strong and distinct scent that might not be universally described as pleasant—it literally smells like insect repellent. However, scent perception is subjective, and some people may find it appealing. It's worth noting that the intensity of the scent can vary between pieces and typically diminishes gradually over time.
Hiba trees encompass both the fundamental species Asnaro and its variant, Hinoki Asnaro, both of which are native to Japan. In 1901, Shizuroku Honda, the first forestry doctor in Japan, identified distinctions between the conventional Asnaro and the Asnaro species found in Aomori Prefecture. Tomitaro Makino, "Father of Japanese Botany", designated it as "Hinoki Asunaro," categorizing it as a subspecies of the Asnaro genus. This variant is now recognized as Aomori Hiba when referring to Hinoki Asunaro grown in the Aomori region, where 80% of the country's Hiba reserves exist.
Asunaro tree from Aomori prefecture - not Hinoki Asunaro (Aomori Hiba) - both look identical
Growing in the cold northern region of Japan, Aomori Hiba cypress trees exhibit an exceptionally slow growth rate, taking approximately 300 years for the trunk to reach a diameter of about 70cm. Due to this slow growth, the wood fibers of Aomori Hiba are densely packed, resulting in a remarkably dense wood structure.
Aomori Hiba (Hinoki Asunaro) belongs to the same Cypress family as Hinoki and shares characteristics as a coniferous tree. It is often compared to Hinoki, which is widely regarded as the most favored tree. While Hiba lumber boasts a slightly yellowish hue, Hinoki showcases a pale red color.
Hiba is a pure, natural wood untouched by human intervention, which makes twisting and bending common. Some uneven patterns may also appear on its surface. In contrast, Hinoki trees are carefully pruned and maintained, as they are often cultivated for centuries, resulting in a more uniform appearance.
Motivated by a strong local attachment to Hiba, a rivalry with Hinoki, or perhaps a combination of both sentiments, I have encountered claims from Hiba vendors asserting that Hiba wood possesses superior antibacterial properties compared to Hinoki. These claims often highlight a misconception that Japanese Hinoki contains Hinokitiol, emphasizing instead that Hiba does. While it is true that Japanese Hinoki has little to no Hinokitiol, this misunderstanding likely stems from the fact that Taiwanese Hinoki does contain the compound, which is where Hinokitiol was first discovered.
Although there is no dispute about the lack of Hinokitiol in Japanese Hinoki, I find such claims to be misleading. In the aforementioned report by the Japan Anti-Termite Association, nine different tree species were tested against termites. Japanese Hinoki cypress ranked a close third, following Aomori Hiba (Hinoki Asunaro) and Buddhist Pine. Interestingly, Asunaro from Miyazaki Prefecture ranked a distant fourth.
According to Professor Yatagai from the University of Tokyo, the antibacterial properties of Japanese Hinoki are not primarily attributed to Hinokitiol but to other compounds such as α-cadinol and Honokiol. Notably, α-cadinol demonstrates even stronger antibacterial properties than Hinokitiol.
That said, the primary factor influencing the antibacterial performance of a cutting board is whether it is made from heartwood, which is rich in antibacterial resin. Unfortunately, few vendors accommodate requests for cutting boards specifically crafted from heartwood, making it largely a matter of luck to obtain one. Nonetheless, both Aomori Hiba and Hinoki possess strong antibacterial properties, making them excellent choices.
