Sugi: Japan’s Cedar Landscape
Japanese cedar (Cryptomeria japonica), known as sugi, is the country’s most extensively planted timber tree — covering approximately 4.4 million hectares, or about 18% of Japan’s total forested area. The characteristic dark green, columnar sugi forest is one of Japan’s defining landscape elements: it lines the approaches to major shrines and temples (the famous avenue to Nikko, the Kumano Kodō paths, Hakone’s old highway), blankets the mountain slopes of the Yoshino valley, and forms the commercial timber plantations that cover much of central and western Honshu’s interior.
Sacred Sugi Groves
Sugi has been associated with sacred sites in Japan since the introduction of shrine architecture in the early historical period. Ancient sugi — some exceeding 1,000 years of age and 50 metres in height — mark the boundaries and approaches of major shrines. Notable sacred sugi include the approach avenue to Nikkō Tōshō-gū (planted in 1648 by Todo Takatora; nearly 13,000 original trees over 35km, listed as a national heritage site), the ancient sugi of Kiso Valley in Nagano along the Nakasendo highway, and individual giant sugi such as the Mihashira no Sugi on Yakushima, dating to approximately 3,000 years of age.
Yakushima: Ancient Forest
Yakushima island in Kagoshima Prefecture contains Japan’s most celebrated ancient sugi forest and is a UNESCO World Heritage Site designated specifically for its temperate rainforest with trees of exceptional age. Yakusugi — sugi over 1,000 years old — survive on the island’s interior mountains due to the island’s extreme rainfall (up to 10,000mm annually in the interior) and the preservation of the high-altitude forest from historical logging. Jōmon Sugi, estimated at 2,000–7,200 years old, stands at 1,300m altitude and requires a 10-hour round-trip hike from the trailhead at Arakawa. The forest around the Shiratani Unsuikyo ravine, accessible on a shorter 3–4 hour trail, provided visual reference for the forest in Studio Ghibli’s Princess Mononoke.
Pollen Season
Japan’s extensive sugi plantations produce the country’s most significant allergy event: sugi kafunshō (cedar pollen allergy season), which runs approximately from February through April and affects an estimated 30–40% of the Japanese population. The severity peaks in the Kanto, Tokai, and Kinki regions where plantation density is highest. Visitors with grass or tree pollen allergies should note that the season coincides with cherry blossom season; antihistamines are widely available at Japanese pharmacies without prescription.
Timber and Craft Use
Sugi timber is Japan’s most common construction wood — used for structural framing, interior panelling, and the distinctive scented cedar bathtubs (sugi-buro) found in traditional ryokan. Sugi forests in Yoshino (Nara), Tenryū (Shizuoka), and Kitayama (Kyoto) are known for producing premium-grade sugi with tight growth rings, managed by centuries of selective thinning. Kitayama sugi — the polished, straight cedar columns used in tea rooms and tokonoma alcoves — is among Japan’s most prized architectural timbers. Artisan workshops in Kyoto’s Kitayama district offer guided factory visits showing the cultivation and finishing of these timber grades.