The trunks are between 25 m and 40 m high. The 15-20 m long log has a diameter of 0.5-0.9 m, maximum 1.2 m.

The heartwood of the koto is yellow-white in colour. In daylight, it eventually becomes more brownish. The sapwood, which can be up to 100 mm thick, is also yellowish white and cannot be clearly distinguished from the heartwood. In dried wood, it is no longer possible to distinguish the heartwood from the sapwood. 

At the end of the growth ring, the vessels are fewer in number and smaller in diameter than at the beginning. The vessels become large and scattered. 

The wood rays are visible on the crowns slices of the dead wood as a kind of fine striation and on the quarter slices as mirrors. The other parenchyma tissues are visible as almost white to yellowish-grey bands. On the quarter of the wood, light flames or bands of light lustre can be seen. The overall appearance of the koto is a light coloured matte and glossy wood with a discreet texture.