Kajima Corporation is building “KAJIMA TREE” as one of the Village pavilions at GREEN×EXPO 2027. Much of its timber comes from the Grand Ring at Expo 2025 Osaka, Kansai, and Kajima is one of the recipients of that timber.
KAJIMA TREE among the Village pavilions
The venue is run by the GREEN×EXPO Association (formally the 2027 Japan International Horticultural Expo Association). It describes the Village exhibits as a co-creation programme that combines displays with hands-on experiences. Companies and groups put up pavilions in five Villages on the grounds, each working toward the Expo’s theme, “Scenery of the Future for Happiness.” The Association’s page introduces 12 Village pavilions in all, and KAJIMA TREE is one of them.
Most of the other 11 pavilions on that page are centred on newly built exhibits. Tokyu Group’s “Tokyu Group Pavilion” is themed on a future where nature and the city merge, and KT Group’s “KT GROUP Mobi+” on mobility and energy. KAJIMA TREE is different: its building material, the Grand Ring’s timber, already existed.
What KAJIMA TREE is
According to the Association’s page, KAJIMA TREE is a symbol of GREEN×EXPO that tells a story of tomorrow for nature and people. The page says it is built from timber used in Expo 2025’s Grand Ring, put to use again through advanced technology. It also notes that Kajima is a recipient of the Grand Ring’s timber.
Kajima’s dedicated site presents KAJIMA TREE in the same way. Kajima Corporation is a Village exhibit partner of GREEN×EXPO 2027, and the site calls the building a tower representing new scenery for future city-building. What visitors will be able to see or do inside had not been announced as of September 2026.
Construction technique and scale
According to Kajima’s site, the structure of KAJIMA TREE reuses Grand Ring timber. The site says the building combines the beauty of traditional Japanese architecture with Kajima’s own advanced technology, and that its structure is built to flexibly absorb energy from wind and earthquakes.
On scale, the site gives a height of roughly 60 metres, comparable to a 20-storey apartment building, and calls it one of the largest reclaimed-timber buildings in Japan. It presents the project as part of a wider effort toward decarbonisation, resource circulation and nature-positive outcomes.
Before construction began, a 1:100 model of KAJIMA TREE was unveiled on 13 May 2026 at an event called the Non-Residential Wooden Construction Fair 2026. Detailed specifications, such as how the timber is processed and which parts it is used for, had not been announced as of September 2026. Neither had a completion or opening date.
Timeline of announcements
| Date | Announcement |
|---|---|
| 13 May 2026 | A 1:100 model of KAJIMA TREE was unveiled at the Non-Residential Wooden Construction Fair 2026 (per Kajima’s site) |
| 9 June 2026 | Construction of KAJIMA TREE broke ground (same source) |
Groundbreaking came less than a month after the model was unveiled, so construction preparations seem to have moved quickly in the first half of 2026. When the pavilion’s name was finalised, and whether attendant staff have been recruited, could not be confirmed as of September 2026.
Our take
At roughly 60 metres, KAJIMA TREE should be one of the more conspicuous of the 12 Village pavilions. We think turning Grand Ring timber into a new building, rather than simply retiring it after dismantling, is a clear example of what carries over from Expo 2025 (see our feature From Expo 2025).
By calling it one of Japan’s largest reclaimed-timber buildings, Kajima seems to want it noticed for its size as well as for where the timber came from. What visitors will actually see or do inside, though, is not covered by the sources used for this article. We will update this once an opening date and interior details are announced.
For the full pavilion lineup, see our feature page Pavilions.