Japanese timber company Sumitomo Forestry has revealed plans for the world's tallest wooden building in Tokyo, a 350-metre skyscraper that would also be the country's highest.

Sumitomo Forestry is proposing the 70-storey hybrid timber skyscraper to mark the company's 350th anniversary in 2041.

Named W350, the ambitious tower would be almost four times higher than the world's current tallest timber building – the 18-storey Brock Commons Student Residence in Vancouver, Canada.

At 350 metres, the skyscraper designed by Sumitomo's Tsukuba Research Laboratory in collaboration with Tokyo practice Nikken Sekkei, would also become Japan's tallest building.

Timber is expected to make up 90 per cent of the hybrid structure, with 185,000 cubic metres of wood planned to be used in its construction.

The building would use a "braced tube structure" with columns and beams made from steel and timber, supplemented by additional diagonal steel braces.

The multi-use tower containing a hotel, residential units, offices, and shops would be wrapped in large balconies covered in plants.

"The aim is to create an environmentally-friendly and timber-utilising cities where they become forests through increased use of wooden architecture for high-rise buildings," said a statement from Sumitomo Forestry.

"The greenery connects from the ground to the top floors through the balcony part, and it offers a view of biodiversity in an urban setting," it continued. "The interior structure is of a pure wood, producing a calm space that exudes the warmth and gentleness of wood."

Sumitomo Forestry estimates the building will cost £4.2 billion – "almost double that of a conventional high-rise building constructed with current technology."

However, the company is working to reduce these costs by developing new technology. It also intends the building to be part of a wider push to encourage the use of timber in urban areas to "change cities into forests".

Although historically the majority of buildings in Japan were constructed of timber, fire risk greatly reduced the number of wooden buildings. The construction of  buildings made from timber was given a boost in 2010, when the Act for Promotion of Use of Wood in Public Buildings was put in place.

In Tokyo, timber is being used prominently on Kengo Kuma's stadium for the 2020 Olympics.

The plans for W350 are the latest in a series of proposals for conceptual timber skyscrapers. PLP Architecture revealed a concept for a 300-metre-tall addition to the Barbican housing estate in London, while architecture firm Penda proposed a timber-framed high-rise for Toronto.

W350 Plan project credits:

Concept and timber engineering: Sumitomo Forestry Co., Ltd.
Architectural and structural design: Nikken Sekkei Ltd
Chief design officer: Tomohiko Yamanashi
Senior design director: Tatsuya Hatori
Design director: Hajime Aoyagi
Senior project architect: Miwako Kase