Ash has a straight and open grain, like oak. The heartwood ranges from light to medium brown, depending on the species, and the sapwood is nearly white. It is the light-coloured sapwood that is generally preferred.

The dense summer growth of the ash annual rings are connected by porous honeycomb structured spring growth. It is the denser summer layers that are prized for basket making. They are separated by soaking ash in water and pounding it to breakdown the relatively weak spring layers and allow the dense summer growth strips to be peeled off to make splints, which are woven into strong structures.

Untreated ash is limited to indoor applications, because it is not sufficiently durable to survive outdoors. As a thermally modified timber (TMT), such as thermowood, it is suitable for use outdoors and can survive many years in decking and cladding, for example.

White ash (Fraxinus Americana) and black ash (Fraxinus Nigra) are the most common and commercially important. There are several species that are closely related to, and almost the same as, white ash. These include green ash (Fraxinus pennsylvanica), Oregon ash (Fraxinus latifolia) and European ash (Fraxinus excelsior). Compared to black ash, white ash tends to be a little heavier, harder, stronger and lighter coloured. However, the two can be almost indistinguishable and are used in many of the same situations.