Ash
Hardest native wood — extremely durable and elastic.
Ash, with a Brinell hardness of approximately 38 N/mm², is the hardest native timber and thus even more resistant than oak or beech. It combines extreme hardness with high elasticity and a lively, light grain. Ash is excellently suited for heavily used staircases. Thermally modified ash (thermo-ash) achieves a durability class of 1–2 and can even be used for outdoor stairs.