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  2. Flowering Plants Native to Manitoba
  3. bur oak

bur oak

Quercus macrocarpa

Identification of bur oak in Manitoba 2

The bur oak is the only oak native to Manitoba making identification of Manitoba oak trees much simpler than in other regions.

"A small deciduous tree with a broad rounded crown composed of variously spreading stout branches"

Individual trees may live to well over 200 years. Large specimens can survive as shade trees even within cities. In Manitoba, the normal height range is between 15 to 20 m (50 to 65 ft) tall) but some are known to grow over 31 m (100 ft). Trees growing in persistently dry habitats may never grow taller than half the normal height. Their short stature in relation to oaks growing in other regions earned them the local name of 'scrub oak'. Where moose, elk, whitetail deer or mule deer are common, the lower branches may show the effect of repeated browsing with many short twigs arising near the ends of the branches.

"Fruit: an acorn, 3/4 to 1 1/4 inches [1.5 to 2.5 cm] long, half covered by cap, maturing in one year"

Oak seeds or acorns are a valuable food resource for many animals from tiny weevils that bore into the hard shells to deer and black bears. Blue jays and squirrels both collect ripe acorns and hide them to eat later. Some of these hidden food caches remain uneaten and grow into new oak trees. Blue jays have been found to have a significant role in establishing new oaks through this habit.

"Leaves: alternate, simple, prominently lobed, 4-10 inches [10 to 25 cm] long, finely hairy beneath"

Bur oaks leaf out later than the other deciduous trees in the region. Initially the new leaves have a yellow green colour which changes as they mature to a darker green than the leaves of other deciduous trees found in the region. In fall, leaves turn gold then light golden brown. Leaves retain their characteristic shape long after they have fallen to the ground.

The leaves are shiny above and somewhat leathery in texture. Generally leaves are widest two thirds along their length from the stem. The specific shape and size of the leaves varies according to the light and air movement that the leaf is exposed to.

A variety of smaller organisms exploit the durable structure of the leaves to create secure environments (complete with food supply) for their young. The unique colours and shapes of these 'galls' in combination with the identity of the host plant can provide additional identifiable observations.

"Flowers: After leaves, male in catkins, female single or few in cluster"
"Bark: light brown, rough, divided by deep furrows into scaly flaky plates."
"Twigs: Alternate, stout, ridged, hairy at first but becoming hairless. Lenticels small, oval, yellowish-brown. Terminal bud hairy, about 1/8 inch [3 mm] long, surrounded by five narrow hairy bracts and two or more lateral buds; lateral buds about the same size. Leaf scars moon-shaped, raised, brown; bundle scars in two curved rows, yellowish, not prominent."

Quoted descriptions all from A Field Guide to the Native Trees of Manitoba

Ecology 2

Bur oak is a deep rooted species that can tolerate intermittent drought. It is not usually found in wet habitats such as marshes, swamps or bogs.

Bur oaks are not able to tolerate much shade and form a minor component in mixed forests of larger trees. Thick stands of oak saplings will develop into oak forests of mature trees spaced so that each tree's canopy touches the the ones surrounding it. Other plants living in such a forest have to make the most of the early spring growing period before the sunlight is blocked by the oak canopy.

Historically, bur oaks grew in scattered stands on the tall grass prairie where their thick corky bark enabled them to survive the occasional prairie fire. Very little of this oak savannah can be still found in Manitoba as agricultural clearing has removed much of the prairie.

Where does it grow? 2

In Manitoba, Quercus macrocarpa is found throughout the southern third of the province. The northern edge of its range runs roughly northwest from southeastern Manitoba up to Berens River on the east shore of Lake Winnipeg and then west to the north end of Lake Winnipegosis and the Saskatchewan border.

The native range of Quercus macrocarpa is temperate eastern America from Saskatchewan through south-central Manitoba, east to New Brunswick, south to Texas, Alabama and North Carolina.

More names... 2

French: chêne à gros fruits Database of Vascular Plants of Canada (VASCAN)

Michif: shen Michif language resources

Ojibwe: mitigomizh the Ojibwe People's Dictionary

Plains Cree: ᒥᐢᑎᑯᒥᓈᐦᑎᐠ mistikominâhtik nēhiýawēwin Plains Cree Dictionary

Dakota: utahuçaå Dakota Dictionary Online

English: scrub oak A Field Guide to the Native Trees of Manitoba, burr oak, mossycup oak, blue oak Database of Vascular Plants of Canada (VASCAN)

Scientific name and Taxonomy 2

Quercus is the genus name that is applied to all oak trees; it is the word the Romans are thought to have used for this type of tree in the Latin language. Macrocarpa is the name applied to this species in 1801 by André Michaux in Histoire des chênes de l'Amérique describing the oaks found in the Americas. The word refers to the large fruit.

Worldwide, the genus Quercus is thought to include about 600 species, the majority of these are trees found in the temperate zones. North America has over 200 native species while China has about 100.

Quercus macrocarpa is the only native member of the Fagaceae or Beech family growing in Manitoba. The family includes about a dozen genera, most of them trees. They are thought to have evolved first in Southeast Asia and from there spread to the rest of Asia, Europe and North America.

The Fagaceae are included in the order Fagales or Beeches, Oaks, Walnuts, and Allies. Manitoba has native plants that belong to the Betulaceae or Birch Family which includes the birches, alders and hazelnuts.

Associated Species 2

Populus tremuloides - Trembling Aspen (RG)

Understory
Corylus cornuta - Beaked hazelnut (RG)
Corylus americana - American hazelnut (RG)
Symphoricarpos occidentalis - Western snowberry (RG)
Rhus glabra - Smooth sumac (RG)
Crataegus - Hawthorn (RG)

Mammals
Cervus canadensis - Elk or Wapiti (RG)
Odocoiles virginianus - White-tailed deer (RG)
Odocoileus hemionus - Mule deer (RG)
Ursus americanus - Black bear (RG)
Tamiasciurus hudsonicus - American red squirrel (RG)
Sciurus carolinensis - Eastern Grey squirrel (RG)
Tamias striatus - Eastern chipmunk (RG)
Neotamias minimus - Least chipmunk (RG)
- raccoon
- mice

Birds
- Blue jay
woodpecker
flicker
wood duck
grouse

Fungi
Botryosphaerostroma quercina -
Bretziella fagacearum - Oak wilt
Armillaria mellea - Honey Mushroom, shoestring root rot (RG)
Taphrina caerulescens - Oak Leaf Blister (RG)

Insects and other arthropods

Aceria triplacisa (RG)
Acraspis gemula (RG)
Acraspis macrocarpae - Jewel Oak Gall Wasp (RG)
Acronicta lobeliae - Greater Oak Dagger (RG)
Agrilus bilineatus - Two-lined Chestnut Borer
Andricus chinquapin - Small Oak Spindle Gall Wasp (RG)
Andricus dimorphus - Clustered Midrib Gall Wasp (RG)
Andricus foliaformis (RG)
Andricus ignotus (RG)
Andricus incertus (RG)
Andricus quercusfrondosus - Oak Rosette Gall Wasp (RG)
Andricus quercuspetiolicola - Oak Petiole Gall Wasp (RG)
Andricus quercusstrobilanus - Lobed Oak Gall Wasp (RG)
Anisota manitobensis - Manitoba Oakworm Moth (RG)
Archips semiferanus - Oak Leafroller Moth (RG)

Besma quercivoraria - Oak Besma Moth

Callirhytis flavipes (RG)
Callirhytis quercusfutilis - Oak Wart Gall (RG)
Catocala ilia - Ilia Underwing
Catocala micronympha - Little Nymph Underwing
Cameraria macrocarpae -
Curculio iowensis - Acorn weevil

Disholcaspis quercusmamma - Oak Rough Bulletgall Wasp (RG)

Empoa casta -

Lymantria dispar - LD Moth

Malacosoma disstria - Forest Tent Caterpillar

Neuroterus fugiens (RG)
Neuroterus quercusverrucarum - Oak Flake Gall Wasp (RG)
Neuroterus saltarius - Jumping Oak Gall (RG)

Olethreutes atrodentana -

Periclista albicollis -
Philonix nigra (RG)
Phylloteras volutellae (RG)

Satyrium edwardsii - Edwards' Hairstreak

Manitoba RG observationswhere the host plant of the organism observed is identified as Bur Oak

Fontes e Créditos

  1. (c) Mary Krieger, alguns direitos reservados (CC BY-NC), uploaded by Mary Krieger
  2. (c) Mary Krieger, alguns direitos reservados (CC BY-SA)

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