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Green Ash (Fraxinus pennsylvanica)

Also known as red ash.

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Green Ash


A widely-distributed tree found mostly in floodplains, riparian areas, and swamps, and occasionally found on drier sites.

Range - Expand


This tentative map is based on the FHWA's ERA. This data lacks information on Canada, but also overestimates native ranges, especially around the edges, as this post explains. We have not yet reviewed or fixed this map.

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Most frequently found in wet, poorly-drained areas, including floodplains, riparian areas, and swamps, but also found in drier habitats. Tolerates a wide range of soil types, ranging from poorly-drained to well-drained. Less frequent and grows less vigorously on coarse, sandy soils, and only found on these soils if near a source of water. Tolerant of alkaline soils and often found on calcareous soils. Found on sites that flood temporarily, but not tolerant of continuous flooding.

Occupies different successional stages, depending on conditions and location. On well-drained sites protected from disturbance, in the northeast, green ash is only a pioneer species.

Life Cycle

Green ash is a fairly weedy tree that grows rapidly, produces prolific seeds, and can also reproduced vegetatively.

Seedlings establish best in partly-shaded sites, in moist soil or litter. Seedlings are able to survive some flooding, including up to two months of water 1 inch above the soil, and seedlings may even grow faster in saturated soil than in more well-aerated conditions. However, seedlings are killed by prolonged, deeper flooding that covers them.

Trees tend to experience multiple flushes of growth in one season, and growth rates are often higher on sites that experience greater flooding.

This species is dioecious, with male and female flowers borne on separate trees. Flowers are wind-pollinated. Trees may flower and produce some seed when they reach about 3-4 inches in diameter, but significant seed production usually begins when trees reach 8-10 inches in diameter. Patterns of seed production are variable by site and conditions, with some trees producing consistent seed every year, but others producing less seed in a typical year and having bumper crops at intervals every 5 years or even longer.

Seeds are primarily distributed by wind, but dispersal may also be aided by water, especially given this species' propensity to be found in wetlands. Seeds shed in winter typically travel farthest from the parent tree, especially when they fall on crusted snow.

Seeds require a period of cold dormancy, and germinate only in the following spring. This species can form a short-term seed bank, typically up to 3-4 years, depending on conditions. In some areas and conditions, there is no seed banking. Seeds can germinate in flooded conditions.

Trees resprout vigorously following disturbance, including fire, logging, or damage from flooding.

Trees can live to 200-250 years, but are often shorter-lived.


The red ash is usually considered a subspecies of this species, Fraxinus pennsylvanica pennsylvanica.

Green Ash | The Wood Database (About This Site)

Green Ash | Fire Effects Information System (FEIS) (About This Site)

Fraxinus pennsylvanica (Green Ash) | USDA PLANTS Database (About This Site)

Fraxinus pennsylvanica | Go Botany (About This Site)

Fraxinus pennsylvanica (Green Ash) | Missouri Botanical Garden Plant Finder (About This Site)

Green Ash | Virginia Tech Dendrology Factsheets (About This Site)

Green Ash | Silvics of North America (About This Site)

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