The natural order Oleaceae includes a number of species of the genus Fraxinus or ash, whose timber is characterised by good strength elasticity, toughness, stiffness and hardness, allied to relatively light weight. The following are the principal species found in North America:
Black ash Fraxinus nigra
Green ash Fraxinus pennsylvanica
White ash Fraxinus americana

The Timber

BLACK ASH

The timber is greyish-brown to brown in colour, darker than that of white ash, (F. americana} and inferior to that timber in general strength properties and lighter in weight, about 560 kg/m³ when dried. A certain amount of this species is used for interior trim and fittings It takes a good finish.

GREEN ASH

Produces timber similar to American white ash in appearance, but inferior to that timber in hardness, strength and toughness. It weighs about the same as white ash, about 670 kg/m³ when dried and is used for similar purposes as white ash, except for striking tool handles.

WHITE ASH

The sapwood is almost white in colour and the heartwood varies from light brown to reddish-brown rather similar to European ash. but a little lighter in weight, about 670 kg/m³ when dried.