& H
Carolinian Forests    
"What is a Carolinian Forest?"

An avid gardener with an interest in natural history walks into an Ontario garden centre and asks to see some Carolinian species. The centre carries, among others, american beech, tuliptree, carolina poplar and rhododendron caroliniense. Which of these should be offered for purchase? Unsure? Confused? You are not alone. Forester, landscaper, naturalist, biologist, neighbour and friend alike can be perplexed by this term (and if they're not they should be, as we will see). So ask us which of the above species are Carolinian and we would safely say only that the rhododendron isn't native and the poplar is a horticultural hybrid. Tulip tree flower:  Dave's Garden

How did we reach this muddle; who do we blame? Let's start way back in 1629. In that year King Charles I granted his attorney general Sir Robert Heath the southern part of the English claim in America called the Province of Carolana (land of Charles). In some fashion, not explained in encyclopedias, this was corrupted to Carolina. Then the area was chopped into a North and South to become the states we like to golf in today.

Historical Origins of the term "Carolinian"

But back to biology - in 1859, J.G. Cooper used the term Carolinian to describe a forest region running in a strip along the Atlantic coast from southern Long Island to Georgia. This appears to be the first use of the term in a biological rather than geographical sense. In 1892, J.A. Allen used Carolinian for a faunal region stretching from the Carolinas to New Jersey and west to South Dakota and Oklahoma. Both Allen and Cooper excluded southern Ontario from their Carolinian regions. In 1898 C.H. Merriam published his influential 'Life Zones and Crop Zones of the United States'. Merriam used isotherms as well as plant and animal ranges to define a Carolinian Area. "Counting from the north - the Carolinian Area is that in which the sassafras, tulip tree, hackberry, sycamore, sweet gum, rose magnolia, redbud, persimmon, and short-leaf pine first make their appearance together with the opossum, gray fox, fox squirrel, cardinal, Carolina wren, tufted tit, gnatcatchcr, summer tanager, and yellow-breasted chat. Chestnuts, hickory nuts, hazel-nuts, and walnuts grow wild in abundance."

Merriam's study correlated crop adaptability with the life zones of the native plants and animals. For example, peaches do well where chestnut grows. Southern Ontario from the north end of Lake St. Clair to the west end of Lake Ontario was included in his Carolinian Area.

pawpawIn 1915, Canadian researchers Macoun and Malte used Carolinian to identify the vegetation in southern Ontario bounded by "a line running approximately from the northern shore of Lake Ontario to Windsor". They characterized the vegetation as "the Hickories (6 species), the Oaks (10 species), the Black Walnut (Juglans nigra), the Chestnut (Castanea dentata), and the Sycamore (Platanus occidentalis). Less abundant and more local in their distribution are: Cucumber tree (Magnolia acuminata), Tuliptree (Liriodendron tulipifera), Flowering Dogwood (Cornus florida), which have all beautiful and very conspicuous flowers, Papaw (Asimina triloba), Red Mulberry (Morus rubra), American Crab Apple (Pyrus coronaria), Sour Gum (Nyssa sylvatica), Sassafras (Sassafras variifolium) and others."

"The herbaceous vegetation is very rich, at least a hundred species occurring nowhere else in Canada being found in the zone. A few of the most conspicuous may be mentioned, viz.: Yellow Nelumbo or "Lotus Flower" (Nelumbo lutea), May Apple (Podophyllum peltatum), Wild Lupine (Lupinus perennis), Tick Trefoil (Desmodium), Flowering Spurge (Euphorbia corollata), Swamp Rose Mallow (Hibiscus Moscheutos), Wild Pansy (Viola Rafinesquii~, Prickly Pear (Opuntia Rafinesquii~, Poke Milkweed (Asclepias phytolaccoides), Wild Potato Vine (Ipomoea pandurata), Downy Phlox (Phlox pilosa), Waterleaf (Hydrophyllum appendiculatum), Bee Balm (Monarda didyma), Foxglove (Gerardia pedicularia, G. virginica),Tall Bellflower (Campanula americana), Great Lobelia (Lobelia siphilitica), Ironweed (Vernonia altissima, V. illinoensis), Dense Button Snakeroot (Liatris spicata), Prairie Dock (Silphium terebinthinaceum), Cup Plant (Silphium perfoliatum), Sunflower (Helianthus decapetalus, H. divaricatus), Tall Coreopsis (Coareopsis tripteris), Indian Plantain (Cacalia tuberosa). Golden Seal (Hydrastis canadensis) and Ginseng (Panax quinquefolium) were at one time abundant but are now practically extinct."


In 1938 another Canadian, John Adams, mapped an "Interlacustrine or Carolinian Region" with a northern limit along a line from approximately Toronto to Sarnia. He listed most of the same species as restricted to the region as Macoun and Malte. Finally Dice (1943) defined a Carolinian Biotic Province which essentially followed that of Allen & Merriam but excluded most states west of the Mississippi and included Ontario below a line from Grand Bend to Toronto.


Swamp Rose Mallow: Donald Kirk

After this the term should have gone off to die in some biogeographical boneyard because other terms were ascendent. For example W. Halliday (1937) in his 'Forest Classification for Canada' outlined a Deciduous Forest Region described as "The rather low-lying portion of the Ontario peninsula, enclosed by lakes Ontario, Erie, and Huron... The associations are predominantly composed of broad-leaved trees. A large number of these species, many of small size, find their northern limit here. Amongst these are chestnut, tuliptree, mockernut and pignut hickories, chinquapin, chestnut, scarlet, black, and pin oaks, black gum, blue ash, magnolia, papaw, Kentucky coffee tree, redbud, red mulberry, and sassafras. In addition, within this Section is the main distribution for Canada of black walnut, sycamore, swamp white oak, the shagbark hickory, together with the more widely distributed butternut, bitternut hickory, rock elm, silver maple, and blue beech. 

All these species occur as scattered individuals or groups, either on specialized sites or within the characteristic association for the Section. This association, made up of widely distributed broad-leaved trees common in part to both the Great Lakes - St. Lawrence and the Deciduous Forest Regions, consists primarily of beech and sugar maple, together with basswood, red maple, and (northern) red, white and bur oak. The presence of the species listed above, and the predominance of beech within the characteristic association, indicate a definite relationship to an Ohio centre of distribution. Coniferous species are poorly represented. . .  Map of Ontario: ROM

"Within the Deciduous Forest Region, Halliday mapped a single 'Section' which he called the Niagara Section. [J.S. Rowe in his Forest Regions of Canada (1959, revised 1972) followed Halliday's work and retained the Niagara Section of the Deciduous Forest Region.] In 1950, noted forest ecologist Lucy Braun mapped the area south of the Toronto-Grand Bend line within the Beech-Maple Forest Region of her Deciduous Forest Formation. Why Beech-Maple? The idea was that a mature landscape (ie. well-drained would have a Beech-Sugar Maple community at the termination, the climax, of plant succession. She was clearly influenced by the earlier work on succession and climax communities by Weaver & Clement (1938). This was a time when the concept of climax vegetation was embraced by biologists eager to bring order from nature's chaos.

Mid-20th Century Definitions of the "Carolinian Zone"

So now, at Mid century, Carolinian seemed headed for extinction but instead it was merely extirpated from most of its former range. The reprieve came at the hands of two Canadian academics, J.H., Soper and W.S. Fox.

Soper was curator of the herbarium at the University of Toronto and Fox was retired from the presidency of the University of Western Ontario; you may remember him as author of "The Bruce Beckons" or "T'aint Running No More" (or something like that). From 1952 to 1954 they published three papers entitled "The distribution of some trees and shrubs of the Carolinian Zone of Southern Ontario". In the first of these papers they noted that a floral "territory" (of trees and shrubs particulary) formed a unit in eastern North America "From its northern limit, somewhere in Canada, it stretched into the southland as far as Tennessee and the Carolinas, and even beyond...Captivated by a name redolent of the South, one investigator called, quite appropriately, the last, roughly defined expanse, the Carolinian Zone". They don't name the romantic investigator but in the final paper they provide a genealogy of the word starting in 1859 with J.G. Cooper.

Since the Fox & Soper publications, the term Carolinian has received wide currency among Canadian authors in a variety of fields, appearing in papers by Catling et al. (1992), Cody (1982), Cruise (1969), Maycock and Fahselt (1987) Thaler and Plowright (1973) and of course Soper (1956 & 1962), to name a few.

At some point the 'redolent' quality of Carolinian must have struck a resonant chord within the Ontario Dept of Lands and Forests and the Canadian Parks Service: Pinery and Rondeau Provincial Parks, and Point Pelee National park began proclaiming 'Deep South' Carolinian status.

What Does "Carolinian" Really Mean?

What are we to make of this word Carolinian? Perhaps, like many words, it is evolving; a semantic moving target, blurred, difficult to define. We could make it a colloquial scientific term, a kind of ethnocentric artifact; or a description of a particular community. We could use it as a horticultural term, as a site description for restorative work, or a "nickname" for the Deciduous Forest Region. We could let it evolve until some consensus is reached.

As it is we have a term that is provincial in both senses. Is it reasonable to change terminology at a political border? Perhaps we should use the term Deciduous Forest Region (or Beech-Maple Forest) and retain Niagara Section as token chauvinism. We could reserve Carolinian for communities dominated by the species commonly used to typify the Carolinian Zone; species which are largely restricted to well drained, sandy, often acidic, soils.

Many ecologists, such as Dice (1952), have recognized associations within a biotic province. To quote Dice the association is "a type of community that in aggregate covers an important part of the area of a biotic province". Dice's 'association' is essentially synonymous with the mapping units of W.A. Morsink (1984). Morsink used 5 'Deciduous Forest Mapping Units' for the forest vegetation of Essex, Kent & Lambton Counties in Ontario. These included "Carolinian Upland Hardwoods". This contained Sassafras, Flowering Dogwood, Tuliptree, Black Gum and American Chestnut as well as Sugar Maple & Beech.

The concept of plant "association" was also recognized by both Halliday and Rowe. We can add further confusion at this point by noting that some researchers, of which Maycock is a good example, have emphasized the futility of defining associations because of the "continuous characteristics of forest patterns within the Deciduous Forest Formation".

What's our preference you will likely ask? Well, we would like to see Deciduous Forest Region used instead of Carolinian Zone. We would prefer Carolinian as a label for those associations within the Deciduous Forest Region in which Sassafras and Tuliptree are dominants. Some Flowering Dogwood in the understorey would be nice. Such an association would likely have had a lot of American Chestnut at one time. Co-dominants would include Black Walnut, Black Oak, White Oak, Red Maple, Pignut Hickory, and Black Gum. The species common to the association could be referred to as Carolinian in the nursery trade. By using Carolinian in this way we may lose some of the romance (and redolency) but just might gain some precision from conformity. We wouldn't be surprised if you disagreed.


Adams, J., 1938. The Flora of Canada. Reprinted from the Canada Year Book 1938. revised in 1945. pp 1-38.

Allen, G.M., P.F.J. Eagles and S.D: Price, 1990. Conserving Carolinian Canada. University of Waterloo Press. Waterloo Ontario.

Allen, J.A., 1892. The Geographical Distribution of North American Mammals. Bull. Am. Nat. Hist. 4:199-243.

Braun, L., 1950. Deciduous Forests of Eastern North America. Hafner Press. New York.

Catling, P.M. V.R. Catling and S.M. McKay-Kuja, 1992. The extent, floristic, composition and maintenance of the Rice Lake Plains, Ontario, based on historical records. Can. Field-Nat. 106(1):73-86.

Cody, W.J., 1982. A comparison of the northern limits of distribution of some vascular plant species found in southern Ontario. Naturaliste Can. 109:63-90.

Cooper, J.G., 1859. On the Distribution of the Forests and Trees of North America, with notes on its Physical Geography. Annual Report of the Smithsonian Institute 1858.

Cruise, J.E., 1969. A floristic study of Norfolk County, Ontario. Trans. Roy. Can. Inst. 72:116 pp.

Dice. L.R., 1943. The Biotic Provinces of North America. Univ. Mich. Press. Ann Arbor, Mich.

Dice. L.R., 1952. Natural Communities. Univ. Mich. Press. Ann Arbor, Mich.

Halliday, W., 1937. A Forest Classification for Canada. Forest SeN. Bull. 89. pp 1-50.

Hills, G.A., 1952. The classification and evaluation of sites for forestry. Ontario Dept. Lands & Forests. Res. Rep. no 24.

Lamb, L. and G. Rhynard. 1994. Plants of Carolinian Canada. Federation of Ontario Naturalists. 

Macoun, J. and M.O. Malte, 1916. The Flora of Canada. The Canada Year Book. pp 43-55.

Maycock, P.F., 1963. The phytosociology of the deciduous forests of extreme southern Ontario. Can. J. Bot. 41 :379-438.

Maycock, P. and D. Fahselt, 1987. An inventory of ecologically significant natural vegetation in the province of Ontario: I. Essex County, Can. Field-Nat. 101(3) 474-486.

Merriam. C.H., 1898. Life Zones and Crop Zones of the United States. U.S. Dept. Agric. Div. Biol. Surv. Bulletin No. 10.

Morsink, W.A., 1984. Deciduous forest mapping units and major tree lists for the Essex, Kent and Lambton tri-county area of southwestern Ontario. Ont. Field Biol. 38:17-28.

Rowe, J.S., 1972. Forest Regions of Canada. Canadian Forestry Service. Pub. No. 1300.

Seasons, 1985. A special issue celebrating Carolinian Canada. vol. 25 no. 2 summer. Federation of Ontario Naturalists

Soper, J.H. and W.S. Fox, 1952. The distribution of some trees and shrubs of the Carolinian Zone of Southern Ontario. Trans. Roy. Can. Ins. 61:67-84.

Soper, J.H. and W.S. Fox, 1953. The distribution of some trees and shrubs of the Carolinian Zone of Southern Ontario. Part II. Trans. Roy. Can. Ins. 62:3-32.

Soper, J.H. and W.S. Fox, 1954. The distribution of some trees and shrubs of the Carolinian Zone of Southern Ontario. Part III. Trans. Roy. Ins. 63:99-130.

Soper, J.H., 1956. Some families of restricted range in the Carolinian flora of Canada. Trans. Roy. Can. Soc. 65:69-90.

Soper, J.H., 1962. Some Genera of Restricted Range in the Carolinian Flora of Canada. Trans. Roy. Can. Ins. 70:3-56.

Thaler G.R. and R.C. Plowright, 1973. An examination of the floristic zone concept with special reference to the northern limit of the Carolinian zone in southern Ontario. Can. J. Bot. 51:765-780

Waldron, G. 2003. Trees of the Carolinian Forest: A Guide to Species, Their Ecology and Uses. Boston Mills Press, Toronto.

Weaver, J.E. and F.E. Clements, 1938. Plant Ecology. 2nd ed. McGraw-Hill. New York.

Acknowledgement: Although not referenced above we acknowledge our debt to R.F. Brady et al. who trod much of the same ground in their report "Regional Municipality of Niagara's Environmentally Sensitive Areas". Dept. of Geography, Brock University, St. Catherines, 1980

Essex Region Conservation Authority, 1993

Ken Colthurst, Forester Gerry Waldron, Biologist

Forest Flora    
Forest Fauna    
Old Field & Forest Edge Species    
Tall Grass Prairie & Savanna
Wetlands, Lakes, Rivers & Shorelines
Rare Species & Ecosystems
Uniqueness of Carolinian Canada
Carolinian Indicator Species

Search  |  Contact UsSite Map