Carolinian
and Deciduous Forest Trees

of Southern Ontario

Pumpkin Ash
Fraxinus Profunda

Location in Ontario:
Pumpkin Ash is a Carolinian Tree that grows in small pockets along Lake Erie. It was not identified in Ontario until the early 1990s.


Pumpkin Ash, University of Guelph Arboretum

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:
Pumpkin Ash prefers a swampy habitat.

Landscape Use:
  Everything about Pumpkin Ash is large; its size, leaves and fruit, which make it an interesting lawn specimen. However, it is at risk to Emerald Ash Borer.

Leaves: Pumpkin Ash has opposite compound leaves which are large, up to 25 centimetres long! There are 5-9 leaflets, which are densely hairy beneath.

FALL COLOUR WATCH: yellow to gold

Flowers: Pumpkin Ash is dioecious (male and female flowers on different trees).

Fruit: The seeds of Pumpkin Ash are much larger than any other Ash. Seeds form in summer, and fall off in autumn, with some persisting into winter. Seed production occurs after only 10 years of growth, but is variable, and seeds are never abundant.

Bark: The bark is gray with thin ridges forming a weak diamond pattern.

TREE FACT: In some very wet locations, the base of the tree is swollen like a "pumpkin".

Size: This large tree grows to 30 metres and lives to 100 years.

Wood: Ash wood is hard and heavy. Pumpkin Ash is not commonly used in Canada due to its rareness.
Specific Gravity:
0.52
Janka Hardness: 990 lb
Wood Comparison Chart

Genetics: Pumpkin Ash is always hexaploid with 138 chromosomes; accounting for its large leaves and seeds. There is some thought that it may be a cross between a tetraploid White Ash and a diploid Red Ash, although Pumpkin Ash does reproduce readily on its own.


Pumpkin Ash, University of Guelph Arboretum

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