Bur Oak, J. Sterling Morton's Favorite Tree

Quercus macrocarpa, A Top 100 Common Tree in North America

Bur oak is a classic tree especially adapted to an American mid-western "savanna" timber type. Quercus macrocarpa has been planted and naturally shelters the tree-challenged Great Plains, now and for centuries, even where other introduced tree species have made attempts but failed.  Bur oak is a staple tree in Sterling Morton's Nebraska, the same Mr. Morton that is the father of Arbor Day.

Q. macrocarpa is a member of the white oak family. The bur oak acorn cup has a unique "burry" fringe (thus the name) and is a major identifier along with the leaf's large middle sinus that gives it a "pinched-waist" look. Corky wings and ridges are often attached to the twigs.

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The Silviculture of Bur Oak

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Bur Oak, Arbor Day Farm. Steve Nix

Bur oak is a drought resistant oak and can survive average annual precipitation in the northwestern range as low as 15 inches. It can also suvive average minimum temperatures as low as 40° F where the average growing season lasts only 100 days.

Bur oak also grows in areas having an average precipitation exceeding 50 inches per year, minimum temperatures of 20° F and a growing season of 260 days. The best development of the bur oak occurs in southern Illinois and Indiana.

Acorns of bur oak are the largest in the oak family. This fruit makes up much of the food of red squirrels and are also eaten by wood ducks, white-tailed deer, New England cottontails, mice, thirteen-lined ground squirrels, and other rodents. Bur oak has also been praised as an excellent landscaping tree.

Bur Oak
Bur Oak. Forestryimages.org/UGA
Forestryimages.org provides several images of parts of bur oak. The tree is a hardwood and the lineal taxonomy is Magnoliopsida > Fagales > Fagaceae > Quercus macrocarpa Michx. Bur oak is also commonly called blue oak, mossy cup oak. More »
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The Range of Bur Oak

Bur Oak Range
Bur Oak Range. USFS
Bur oak is widely distributed throughout the Eastern United States and the Great Plains. It ranges from southern New Brunswick, central Maine, Vermont, and southern Quebec, west through Ontario to southern Manitoba, and extreme southeastern Saskatchewan, south to North Dakota, extreme southeastern Montana, northeastern Wyoming, South Dakota, central Nebraska, western Oklahoma, and southeastern Texas, then northeast to Arkansas, central Tennessee, West Virginia, Maryland, Pennsylvania, and Connecticut. It also grows in Louisiana and Alabama.
Leaf: Alternate, simple, 6 to 12 inches long, roughly obovate in shape, with many lobes. The two middle sinuses nearly reach the midrib dividing leaf nearly in half. The lobes near the tip resemble a crown, green above and paler, fuzzy below.

Twig: Quite stout, yellow-brown, often with corky ridges; multiple terminal buds are small, round, and may be somewhat pubescent often surrounded by thread-like stipules; laterals are similar, but smaller. More »

Bur oak bark is thick and fire resistant. Larger trees often survive fire. Bur oak sprouts vigorously from the stump or root crown after fire. It sprouts most prolifically from pole-size or smaller trees, although larger trees may produce some sprouts. More »
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Bur Oak, 2001 Urban Tree of the Year