Forest monolith.

Deep in a Japanese forest, Tadao Ando's new museum devoted to the study of wood is an exquisite exercise in refined elementality; yet this apparently impassive monolith contains surprising spatial drama.

Unlike many of its south-east Asian neighbours, Japan is fortunate to have largely retained its huge swathes of forests. These are highly prized, both as a natural resource and as a reminder of the potency of nature. Historically, timber was also one of the principal materials used in traditional Japanese architecture, fashioned by the needs of priest and peasants alike, giving rise to a rich and complex vernacular. Veneration of wood has long been institutionalised in the annual celebration of National Arbor Day, commemorated this year in its 45th cycle by the opening of a new Museum of Wood, designed by Tadao Ando. Located at Mikata-gun, in the southern prefecture of Hyogo, the museum, appropriately, occupies a site within a forest. The densely wooded surroundings were disturbed as little as possible, so that the building makes an explicit connection with nature, being effectively enveloped by its subject matter.

The museum is conceived as a great truncated cone, 46m in diameter, its gently inclined walls rising impassively out of the forest. This monolithic bulk is clad in horizontally lapped planks of Douglas fir, recalling Ando's earlier Japanese Pavilion at the Seville Expo (AR June 1992), another uncompromisingly simple volume, clad in an almost identical fashion. Both this and the new museum are manifestations of kinari, a quintessentially Japanese concept that extols unadorned beauty as the purest form of aesthetic expression. Here the raw texture and repeated rhythm of the timber cladding embody a powerful elemental quality, despite being ordered by modern functional and formal demands. This elementality heightens the building's curious sense of timelessness; looming through the trees like an abandoned temple to ancient forest gods, there are few clues as to what is concealed within the imposing timber flanks.

The refined minimalism of the exterior is reflected in the simplicity of the plan. The building is essentially a single doughnut-shaped space, 18m high, broken up by quartets of towering laminated cedar columns. The tops of the columns display a tectonic intricacy derived from traditional forms, demonstrating the poetic potential of post and beam construction. Light is filtered through a narrow incision in the roof, casting angular shadows on the plain white walls and reinforcing the spatial drama. A gently curving ramp coils languorously around the interior, marking out a circulation path through the array of exhibits relating to the cultivation of forests and the uses of timber.

At the centre of the museum is a circular courtyard, animated by water and fountains. A secondary ramp penetrates the building at first floor level, bisecting the inner courtyard. Within this artificial forum the sensual play of water is heightened by the concentrated presence of wood and sky - the curving walls of the courtyard are clad in the same lapped planks of Douglas fir as the exterior. The walkway leads out through the building into the forest, eventually connecting with a small cuboid annexe, which offers further views of the landscape. Visitors to the museum experience the wealth of the forest in both practical and didactic ways - the elevated forest path provides a first-hand experience of nature and the museum disseminates how humankind has used this natural wealth through the forces of culture and invention. Subtly responding to the silent grandeur of the forest, Ando's building is imbued with a quiet dignity that will hopefully help to foster an increased sense of awed responsibility towards the natural world.