SYNOPSISFormosan alder (Alnus formosana) was introduced into South Africa in 1982. The species proved to be site specific. On deep, well drained but moist soils it grows fast producing timber in excess of 20 m³/ha per annum at eight years of age. Properties of the juvenile wood indicate a density of 502 kg/m³ at 9% moisture content and pulp strength properties inferior to Eucalyptus grandis, except for burst index. The species increased the soil nitrogen level by 75% in eight years. Its wood is relatively light, easy to work, and gives a good finish. The timber could be used for doors, cupboards, panelling and furniture. Growth models, volume equations and wood properties of young South-African grown trees are presented. The species shows promise for commercial planting in South Africa.