and Deciduous Forest Trees

of Southern Ontario

Black Ash
Fraxinus Nigra

Location in Ontario: Black Ash grows throughout the Deciduous Forest Region and northward.  

Backus Woods, Norfolk County

Genus Fraxinus: Ash trees have opposite compound leaves with 5-11 leaflets. Ash can be monoecious or  dioecious depending on the species. Seeds are contained in a single winged samara (a seed in a papery tissue). Ash wood is valued for its strength and hardness. Black, Red and White Ash grow in Ontario, as well as two Carolinian species, Pumpkin Ash and Blue Ash.

Emerald Ash Borer is an invasive beetle accidently brought to North America from Asia in shipping boxes in 2002. It has quickly spread killing millions of Ash trees. Blue Ash has shown some immunity. There is a pesticide that can be used to control Emerald Ash Borer, but it is very expensive, and must be administered every two years. Unfortunately, many non-infected Ash trees have been cut down as a preventative measure. This eliminates trees that may have had a natural immunity. For more information and encouraging news about saving Ash trees:
Save the Ash Tree Coalition

The tell-tale tracks of the Emerald Ash Borer

Habitat: Black Ash prefer wet, swampy locations.

Landscape Use:
Black Ash is not commonly used as a landscape tree since it prefers wet locations. It is risky to plant, due to Emerald Ash Borer.

Leaves: Black Ash leaves are compound and opposite, with 7-11 leaflets which are stalkless, with dense patches of hairs where they  attach to the main stalk.

TREE FACT: Black Ash buds are very dark, almost black, leading to the name Black Ash.


FALL COLOUR WATCH: yellow to gold

Flowers: Black Ash flowers are small and darkly coloured, and appear in late spring before or with the leaves.

Fruit: Seeds (samaras) form in summer, and fall off in early autumn.  Seed production occurs after 10 years of growth in intervals of 2 to 7 years.

Bark: The bark is light gray with corky ridges, without the "diamond" pattern of the other ashes.


Size: Black Ash is a small, slow growing tree, up to 20 metres high, and short-lived to less than 100 years. 

Wood: Black Ash wood is hard and heavy, but less so than the other ashes. It bends easily so is used for barrel hoops and other applications where bent wood is needed.
Specific Gravity:
Janka Hardness:
 850 lb
Wood Comparison Chart

Genetics: Black Ash is diploid. It does not form hybrids.

Black Ash at the University of Guelph Arboretum