Todai-ji temple, Great Buddha Hall
(image credit: Creative Commons)
Greenery Day (Midori-no-hi) is coming up on May 4th. Officially in Japan, as its name suggests, it is a day to commune with nature and to be thankful for the Earth’s blessings. The day was renamed to recognize the controversial wartime Emperor Shōwa (Hirohito) and his love for plants without directly mentioning his name, and it was shifted by a week back in 2007 to make way for Shōwa Day. However, in practice, it is just another day that expands the Japanese Golden Week vacation. (Similarly, April 26th in many parts of the world was Arbor Day, when people are encouraged, but not required to, to plant trees.)
In honor of that, as architects – we want to make a similar point in regards to contemporary wood construction, specifically in the context of Japan. In fact, in 2021, around 58.7% of housing construction in Japan was wooden structures.(1) Today, most houses in Japan are built of wood, accounting for about 90% of all existing single-family houses in Japan.
This may seem like a hard turn for a topic segue, but at least speaking from the West, the use of Glulam and Cross-Laminated Timber (CLT) construction beyond residential typologies is picking up steam. Architects are thinking more carefully about their building material selections, as we can ill-afford to casually use concrete and steel when greener alternatives exist. To look to Japanese architecture for inspiration, we could have easily extolled the virtues of sashimono (Japanese joinery), miyadaiku (traditional craftspeople who practice the construction of Japanese shrines and temples), or yakisugi-ita (Japanese charred exterior cedar siding); but, it is the contemporary sports stadium or office building that also deserves praise and celebration for showing how architects can integrate wood into our everyday spaces and public places.
Tōdai-ji was the world’s largest wooden building until it was outsized by structures such as Toyo Ito’s baseball stadium, the Ōdate Jukai Dome, built in 1998. In 2022, the Royal Park Canvas - Sapporo Odori Park Hotel was constructed using locally-harvested wood. This year, the Japanese insurance conglomerate Tokio Marine Holdings Inc. announced its plan to replace the current main office with a high-rise largely made of timber by 2028. This new 20-story tall building by Renzo Piano Building Workshop will house the new headquarters of its subsidiary Tokio Marine & Nichido Fire Insurance Co., and is projected to be the largest wooden hybrid structure in the world at the time of its future completion.
Taisho era timber house
(image credit: Kaz)
Generally speaking of Japan’s capital, the Tokyo metropolitan area is only 37.2% made of wooden built structures (the percentage for the Greater Tokyo Metropolitan Region (Greater Kanto Metropolis) is reported at 49%). And for good reason: the Great Kanto Earthquake saw about 40% of Tokyo destroyed by fire. More than 90% of the deaths in the quake were caused by fires. Buildings at the time lacked earthquake and fire resistance, compounding the damage. In addition, the firebombing from World War II destroyed 60% of Tokyo’s wood constructions. The memories of those tragedies were seared into the building codes themselves. Planning of evacuation routes and fire-proofed zones are baked into Tokyo’s urban planning.
However, with modern-day fire proofing/suppression, prevention, and safety, new possibilities for wood construction are being imagined: checking in on Tokyo’s 70-storey W350 “plyscraper,” the tallest planned wooden project in the world, is set to be done by 2041., Another Toyo Ito-designed building, the Mito Civic Center, uses “first-of-its-kind timber design in Japan”, featuring extensive use of fire-proof structural timber, marking the first time such elements have been used to construct large truss structures spanning over 20 meters.
New National Stadium by Kengo Kuma
(image credit: Kaz)
This fresh mentality extends also to Japan’s new take on forest management. Kengo Kuma in his book, My Life as an Architect in Tokyo, speaks of how careful material selection for his partially timber Tokyo National Stadium began with intelligent material caretaking at its source. Historically, Kuma cites that “through a cycle of planting trees, harvesting them for building materials, and planting again, Japan was able to maintain its wood resources. In the twentieth century, however, concrete and steel played a major role in construction, and even when using timber, people turned to cheap sources from overseas. Japan’s forests consequently fell into ruin. Trees extract carbon dioxide from the air, but this capacity is compromised when forests are abandoned.”(1)
Today across Japan, small-scale, self-employed timber harvesting is becoming an essential forest management tool -- as forests account for some 70% of Japan’s land area. To highlight the renewed importance of the Japanese wood construction, Kuma’s Tokyo Stadium uses cedar from all forty-seven of Japan's prefectures.
It is easy to become cynical or complacent when discussing the future of our natural and constructed world, given the on-going climate crisis. As the American Indigenous queer poet Demian DinéYazhi’ notes of the Euro-Western “romanticization and addiction with apocalypse,” it is hard to imagine better alternate futures when you accept catastrophe as a given. This Greenery Day, rather than speculating about our own demise (or a longer vacation), we architects can reflect on how we can imagine and design better, greener futures.
Reference:
(1) Kengo Kuma, My Life as an Architect in Tokyo. London: Thames & Hudson, 2021, 43.
Author: Gregory Serweta, AIA, NCARB
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