Species Profile

Blue Ash

Scientific Name: Fraxinus quadrangulata
Taxonomy Group: Vascular Plants
Range: Ontario
Last COSEWIC Assessment: November 2014
Last COSEWIC Designation: Threatened
SARA Status: Schedule 1, Special Concern

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Quick Links: | Photo | Description | Distribution and Population | Habitat | Biology | Threats | Protection | National Recovery Program | Documents

Image of Blue Ash

Blue Ash Photo 1
Blue Ash Photo 2



Blue Ash is a medium-sized tree that grows up to 20 meters high. It has a straight trunk and a narrow crown that is usually rounded but can have an irregular shape. The compound leaves are opposite and each has 5 to 11 leaflets. The leaflets are elongated oval in shape, dark green above and lighter green underneath and have coarsely toothed edges. The flowers occur in small dense clusters and expand with the new leaves. The fruit or samara is twisted and broad-winged, with a flattened seedcase containing one seed. Twigs are light greyish brown with conspicuous ridges that make them four-sided. The inner bark contains a sticky substance that turns blue when it is exposed to the air.


Distribution and Population

In North America, Blue Ash occurs in southern Canada and in the United States, from Ohio and Wisconsin, south to northern Georgia and Arkansas. In Canada, it occurs only in southwestern Ontario. In the early 1980’s, Blue Ash was known from four areas in Ontario: Point Pelee and nearby islands of southern Lake Erie; the floodplains of the Thames River; floodplains of the St. Clair River; and another site near Lake Erie. In these areas, at least 34 new populations have also been found. The original populations that have since been checked are still present.



Blue Ash occurs in the Carolinian forest of Canada. This area’s climate is moderated year round because of its location near lakes Erie and Huron; it has one of the warmest climates and the longest growing seasons in Canada. In this area, Blue Ash inhabits three types of habitat: rich floodplain forests, shallow soil over dry limestone and well-drained sand. Only the last two types of habitat are used on the islands and spits of southern Lake Erie.



Blue Ash flowers in April and its fruit mature in the fall, normally at the beginning of October. Seeds germinate the following spring. Blue Ash spreads by seed dispersal. There is no evidence of cloning, with the exception of suckers that sprout from the stumps of trees that have been cut. This species may occur as individual trees or as large populations that dominate the local forest in which they are found. Very little is known about the ecological role of the species in Canada.



The main limiting factor for Blue Ash in Canada is probably lack of suitable habitat. Southwestern Ontario is one of the most highly developed parts of the country. Clearing of floodplain forests eliminates trees, and cattle grazing prevents seedling establishment. The populations on Pelee Island may be threatened by proposed quarry or vineyard expansion. Finally, there is little reproduction at some sites.



Federal Protection

The Blue Ash is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.



PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

7 record(s) found.

COSEWIC Status Reports

  • COSEWIC Assessment and Status Report on the Blue Ash Fraxinus quadrangulata in Canada (2015)

    Blue Ash is a medium-sized tree, roughly 20 m in height and up to 80 cm in diameter, and is one of six ash species native to Canada. The trunk can be straight or irregular and the crown is narrow, small and rounded. Trees have light-coloured, reddish-grey or tan-grey, scaly bark. The leaves are compound and opposite with seven (5-11) leaflets and the twigs have square sides with four distinctive corky ridges or wings (hence the scientific epithet quadrangulata). Clusters of small flowers that lack petals are produced in spring, as new leaves are expanding. The fruits are single-seeded samaras that are usually twisted, with a notch in the broad wing. A distinctive feature is the retention of dead lower branches, giving the tree an untidy appearance. The inner bark contains a sticky substance that turns blue upon exposure to air (hence the species’ common name).

Response Statements

  • Response Statement - Blue Ash (2015)

    This tree has a restricted distribution in the Carolinian forests of southwestern Ontario. Small total population size in a fragmented landscape, combined with increasing potential impact from browsing by White-tailed Deer and infestation by the invasive Emerald Ash Borer, place the species at risk of further declines at most sites. In addition, mature trees on Middle Island are threatened by impacts of nesting Double-crested Cormorants. These factors resulted in a change in status from Special Concern to Threatened.

Action Plans

  • Multi-species Action Plan for Point Pelee National Park of Canada and Niagara National Historic Sites of Canada (2016)

    The Multi-species Action Plan for Point Pelee National Park of Canada and the Niagara National Historic Sites of Canada applies to lands and waters occurring within the boundaries of the two sites: Point Pelee National Park of Canada (PPNP) and the Niagara National Historic Sites of Canada (NNHS). The NNHS is being used as a term to collectively refer to two locations in the Niagara region that consist of three National Historic Sites: Fort George National Historic Site, Battlefield of Fort George National Historic Site, and Butler’s Barracks National Historic Sites of Canada. The plan meets the requirements for action plans set out in the Species At Risk Act (SARA s.47) for species requiring an action plan and that regularly occur in these sites. Measures described in this plan will also provide benefits for other species of conservation concern that regularly occur at PPNP and at NNHS.

Management Plans

  • Management Plan for the Blue Ash (Fraxinus quadrangulata) in Canada (2016)

    The Minister of the Environment and the Minister responsible for the Parks Canada Agency are the competent ministers under SARA for the management of the Blue Ash and have prepared this management plan as per section 65 of SARA. To the extent possible, it has been prepared in cooperation with the Government of Ontario as per section 66(1) of SARA.

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2014-2015 (2015)

    Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to "assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species". COSEWIC held two Wildlife Species Assessment Meetings in this reporting year (October, 2014 to September, 2015) from November 23 to November 28, 2014 and from April 27 to May 1, 2015. During the current reporting period, COSEWIC assessed the status or reviewed the classification of 56 wildlife species. The wildlife species assessment results for the 2014-2015 reporting period include the following: Extinct: 0 Extirpated: 1 Endangered: 21 Threatened: 11 Special Concern: 21 Data Deficient: 1 Not at Risk: 1 Total: 56 Of the 56 wildlife species examined, COSEWIC reviewed the classification of 40 that had been previously assessed. The review of classification for 24 of those wildlife species resulted in a confirmation of the same risk status as the previous assessment.

Consultation Documents

  • Consultation on Amending the List of Species under the Species at Risk Act : Terrestrial Species - January 2016 (2016)

    The Government of Canada is committed to preventing the disappearance of wildlife species at risk from our lands. As part of its strategy for realizing that commitment, on June 5, 2003, the Government of Canada proclaimed the Species at Risk Act (SARA). Attached to the Act is Schedule 1, the list of the species provided for under SARA, also called the List of Wildlife Species at Risk. Extirpated, Endangered and Threatened species on Schedule 1 benefit from the protection of prohibitions and recovery planning requirements under SARA. Special Concern species benefit from its management planning requirements. Schedule 1 has grown from the original 233 to 521 wildlife species at risk. Please submit your comments byMay 4, 2016, for terrestrial species undergoing normal consultationsand byOctober 4, 2016, for terrestrial species undergoing extended consultations.For a description of the consultation paths these species will undergo, please see:Species at Risk Public Registry website

Recovery Document Posting Plans

  • Environment and Climate Change Canada's Three-Year Recovery Document Posting Plan (2016)

    Environment and Climate Change Canada’s Three-Year Recovery Document Posting Plan identifies the species for which recovery documents will be posted each fiscal year starting in 2014-2015. Posting this three year plan on the Species at Risk Public Registry is intended to provide transparency to partners, stakeholders, and the public about Environment and Climate Change Canada’s plan to develop and post these proposed recovery strategies and management plans. However, both the number of documents and the particular species that are posted in a given year may change slightly due to a variety of circumstances. Last update March 31, 2017