Distribution

European ash, sometimes called European black ash, is native to Europe and western Asia where it grows best in deep, moist, alkaline soil. It has long been planted as a cultivated tree in Europe and, to a lesser extent, in North America.

Derivation of names

The genus name, Fraxinus, is the classical name for ash. It is derived from the Greek word phraxix, meaning separation, which is in reference to the European use of ash trees as hedges. The species name, excelsior, is from the Latin for taller or higher.

Commercial use

When seasoned, the wood of European ash is particularly flexible and is therefore used for ladders, oars, airplane parts, tool handles, and joists.

The threat of the emerald ash borer

European ash, along with native ash species, is currently threatened by the emerald ash borer (Agrilus lanipennis). This insect pest, brought from Asia, was first detected in the US and Canada, including the GTA, in 2002, and has already killed millions of ash trees. Ash mortality from this pest is expected to be on the scale of the decimation of North American elms from dutch elm disease and American chestnuts from chestnut blight in the 20th century. Removing and replacing dead ash trees will cost municipalities, homeowners, and businesses millions of dollars over the long term.

Because of the threat posed by emerald ash borer, no ash trees of any kind should be planted until effective control and eradication measures are developed. Since the movement of ash wood products like mulch, firewood and logs significantly contributes to the spread of emerald ash borer, these products should not be transported from place to place.

For additional information including symptoms of infection, treatment and implications see: Natural Resources Canada factsheet and City of Toronto factsheet.

Related species

European ash can be distinguished from the native black ash (Fraxinus nigra), by fall colour and by bark. In the fall European ash leaves remain green or turn slightly yellow while those of black ash turn reddish-brown. European ash has firm bark with tight ridges, while that of black ash is soft with corky ridges that turn scaly with age.

European ash's place in Toronto's urban forest

European ash can be found in Toronto's parks and cemeteries, though it is not as widely planted as native species such as red or green ash (Fraxinus pennsylvanica) and white ash (Fraxinus americana).

Landscape value and potential for home planting

Because of the presence of emerald ash borer in our region (see above in Fascinating Facts), no species of ash should be planted at this time.

Find trees on Tree Tour maps at Canadian Tree Tours:

• Toronto Island Park
• Trinity Bellwoods Park
• Queen's Park

• Database of Vascular Plants of Canada (VASCAN)
• USDA PlantsProfile (US Department of Agriculture)