Petrie Island Woods


Resource Inventory

Ottawa Field-Naturalists' Club

September 1977

(This is an unpublished report by A. Dugal of The Ottawa Field-Naturalists’Club, previously submitted to the Planning Staff of the Regional Municipality of Ottawa-Carleton, reformatted and printed in July 1998 without material changes. The lists of species, especially non-plant species, should not be regarded as complete or up to date.)

Location -- Approximately ¼ mile North of junction of Highway 17 and River. Approximately 2 ½ miles East of Orleans.

Type -- Flood plain forest. There was no dominant tree throughout the forested area.

Age -- The woodlot probably ranged between 50 and 70 years.

Canopy Ht. -- Varies between 60-70 feet.


General Comments

The woods as a whole is approaching maturity. There are mature trees scattered throughout but not in great numbers. Mature specimens of basswood, elm, red and black ash, butternut, hackberry, bitternut hickory and silver maple were observed. The composition of the canopy (tree layer) varied from one area to the next. Perhaps this was due to slight changes in elevation and hence drainage. The woods for convenience can be divided into 6 zones, see map. Zone I is the shoreline zone. Here silver maple is quite abundant. Ash and willow trees can also be found. Zone 11 is the hackberry zone. Here basswood, ash and hackberry are the dominant trees. In some areas there are pure pockets of hackberry. Elm, bitternut hickory and butternut also occur but their numbers are few. Zone III is an area rich in butternuts. Zone IV is an area which is dominated by silver maple. Zone V contains a total mix of trees, i.e. elm, ash, hickory, silver maple, hackberry, etc. Zone VI, the eastern end of our study area, is dominated by silver maple, red ash, black ash and elm. The odd hackberry was noticed as well as several butternuts.

Young (4' or less) hackberry trees were noted in Zones III, V and VI. Young red ash, black ash and elm were also observed throughout the woods. Ostrich fern was the dominant ground cover throughout most of the woods. With the exception of Zone VI, shrubs were not abundant in the woodlot. However, in Zone VI Viburnum trilobum formed small thickets. Also in this zone Clematis virginiana formed small patches of ground cover, and along with Virginia creeper, bittersweet and wild grape, was observed climbing into the Viburnum bushes. Menispermum canadense, which is not common in the Ottawa district, was also noted in this area climbing on Cornus rugosa. Several large Vitis riparia vines were seen.



Petrie Island contains the greatest known concentration of hackberry, Celtis occidentalis, in the Ottawa District. Since this tree is quite rare in our region and since it occurs in an even rarer type of forest, i.e. hackberry woods, the Petrie Island woods should be preserved. If it has not been classified as an Area I conservation zone it should be. The wooded areas should be protected from lumbering. No additional cottages should be allowed to be built. The gravel and sand extraction activities should not be allowed to encroach on the wooded areas of Petrie Island. They should also be prohibited from damaging the marshes.

The marshes around Petrie Island are magnificent and provide food, shelter and breeding grounds for waterfowl and many other animals. They should be stringently protected. These marshes are among the finest in the Ottawa district below Ottawa itself.


Preliminary list of plants from wooded area of Petrie Island








Several species of grass


Some plants seen in other parts of Petrie Island

Other types of grass










Response to the River Corridors Study


May 1980.

(Reformatted and printed without material changes July 1998)

The Conservation Committee

The Ottawa Field-Naturalists' Club

Box 3264, Postal Station C Ottawa KIY 4J5

Prepared by Joyce M. Reddoch


Petrie Island - extension of the boundary of Environment Area - Class I

The Hackberry-Butternut-Bitternut Hickory woods on Petrie Island is an unusual forest association in Ottawa-Carleton ([Dugal] 1977). This regionally significant natural feature merits recognition as an Environment Area - Class 1. We do not feel that this woods is adequately protected by the statement that "any future use of the island should avoid disturbance of the hackberry woods" (Main Report p. 80). Thus we propose a northward extension of the area of Class I designation to include the Hackberry-Butternut-Bitternut Hickory woods and surrounding seasonally-flooded forest. (See map below.)


[Dugal, A.] 1977. Petrie Island Woods, Resource Inventory. An unpublished report of The Ottawa Field-Naturalists'Club previously submitted to the Planning Staff of the Regional Municipality of Ottawa-Carleton.