Forest Trees of Illinois Part 5

+SPANISH OAK+ _Quercus falcata_ Michx.

THIS oak, one of the common southern red oaks, ranges from Virginia and Florida to Texas and Missouri, and appears in a dozen of the southern counties in Illinois. It is usually called the Spanish oak, or southern red oak, and has been known as _Quercus rubra_ L. or _Quercus digitata_ Sudw.

[Ill.u.s.tration: SPANISH OAK

Leaf, one-third natural size. Twig, one-half natural size.]

It is a variable species and hence has been known under so many names.

It grows to a height of 70 to 80 feet, and a diameter of 2 to 3 feet, though larger trees are not infrequently found. Its large spreading branches form a broad, round, open top.

The _bark_ is rough, though not deeply furrowed and varies from light gray on younger trees to dark or almost black on older ones.

The _leaves_ are of two different types: (1) irregular-shaped lobes, mostly narrow, bristle-tipped, the central lobe often the longest; or (2) pear-shaped with 3 rounded lobes at the outer end. They are dark l.u.s.trous green above and gray downy beneath, the contrast being strikingly seen in a wind or rain storm.

The _flowers_ appear in April while the leaves are unfolding. The _fruit_ ripens the second year. The small rounded acorn, about half an inch long, is set in a thin saucer-shaped cup which tapers to a short stem.

The _wood_ is heavy, hard, strong, coa.r.s.e-grained and is less subject to defects than most other red oaks. It is used for rough lumber and for furniture, chairs, tables, etc. It is a desirable timber tree, especially on the poorer, drier soils. The bark is rich in tannin.

_Q. rubra_ var. _paG.o.daefolia_, called swamp Spanish oak, has been collected in four southern counties of Illinois.

+BLACK JACK+ _Quercus marilandica_ Muench.

THE black jack oak is a tree of sandy and clayey barren lands where few other forest trees thrive. It ranges from New York to Florida and westward into Illinois, Arkansas, and Texas. It reaches its largest size in southern Arkansas and eastern Texas. It is found as one of the main species in the "Post Oak Flats" in the southern half of the State and in the sands along the Illinois River, near Havana. The tree sometimes reaches a height of 50 to 60 feet and a diameter of 16 inches, but it is usually much smaller. Its hard, stiff, drooping branches form a dense crown which usually contains many persistent dead twigs. The _bark_ is rough, very dark, often nearly black, and broken into small, hard scales or flakes.

[Ill.u.s.tration: BLACK JACK OAK

Twig, two-thirds natural size. Leaf, one-third natural size.]

The _leaves_ are of a leathery texture, dark green on the upper surface, lighter, hairy, and brown-scurfy below. The leaves are wedge-shaped, 4 to 10 inches long and about the same in width. There is a considerable difference in the leaves of this oak both in size and shape.

The _fruit_ is an acorn about three-quarters of an inch long, yellow-brown and often striped, enclosed for half its length or more in a thick light brown cup.

The _wood_ is heavy, hard and strong; when used at all, it is used mostly for firewood and mine props. It is also used for the manufacture of charcoal.

+SHINGLE OAK+ _Quercus imbricaria_ Michx.

THIS oak is found throughout the State with the exception of the extreme north portion. When growing alone, the tree develops a symmetrical rounded top, conspicuous on account of the good-sized, regular-shaped, oblong leaves which differ in shape from most other native oaks. It forms a handsome tree. It is sometimes incorrectly called "laurel" oak.

[Ill.u.s.tration: SHINGLE OAK

Leaf, one-third natural size. Twig, three-fourths natural size.]

The _bark_ is rather thin and divided by shallow fissures into broad ridges of a dark brown color.

The _leaves_ are alternate in arrangement along the stem, oblong in shape, 4 to 6 inches long by 1 to 2 inches wide, leathery in texture with smooth margins sometimes wavy in outline, dark green and shiny above, and thick downy or velvety below.

The _fruit_ is an acorn about one-half inch in length, borne singly or in pairs on stout stems, full or rounded at the end and faintly streaked, enclosed for about one-half its length in a thin-walled cup.

Like all members of the black oak group, the fruit requires two seasons to mature.

The _wood_ is heavy, hard, rather coa.r.s.e-grained, and used for common lumber, shingles (whence it gets its common name), posts and firewood.

The willow oak, _Quercus ph.e.l.los_ L., is a river bottom tree rarely found in southern Illinois. It is readily identified by its leaves, which as the name implies, resemble those of the willows. These leaves are from two to four inches long and one-half to one inch wide, light green, shiny above and smooth beneath.

+AMERICAN ELM+ _Ulmus americana_ L.

THIS is a famous shade tree of New England, whose range, however, extends to the Rocky Mountains and southward to Texas. Within this vast area, it is generally common except in the high mountains. It reaches an average height of 60 to 70 feet and a diameter of 4 to 5 feet. The _bark_ is dark gray, divided into irregular, flat-topped thick ridges, and is generally firm, though on old trees it tends to come off in flakes. An incision into the inner bark will show alternate layers of brown and white.

[Ill.u.s.tration: AMERICAN ELM

Twig, one-half natural size. Leaf, one-half natural size.]

The _leaves_ are alternate, simple, 4 to 6 inches long, rather thick, somewhat one-sided, doubly toothed on the margin, and generally smooth above and downy below. The leaf-veins are very p.r.o.nounced and run in parallel lines from the mid-rib to leaf edge. The _winter buds_ are pointed, brown, ovoid and smooth.

The _flowers_ are small, perfect, greenish, on slender stalks sometimes an inch long, appearing before the leaves in the early spring. The _fruit_ is a light green, oval shaped samara (winged fruit) with the seed portion in the center and surrounded entirely by a wing. This wing has a conspicuous notch at the end and is hairy on the margin, a mark distinctive of the species. The seed ripens in the spring and by its wing is widely disseminated by the wind.

The _wood_ is heavy, hard, strong, tough and difficult to split. It is used for hubs of wheels, saddle trees, boats, ships, barrel hoops, and veneer for baskets and crates.

Because of its spreading fan-shaped form, graceful pendulous branches, and long life, the white elm justly holds its place as one of the most desirable shade trees.

The rock or cork elm, _Ulmus thomasi_ Sarg., is found occasionally in northern Illinois. Its excurrent branches are very different from those of other elms. Its twigs often have corky ridges and the winter buds are somewhat hairy.

The winged elm, _Ulmus alata_ Michx., a small tree, is found in the southern part of the State. The twigs have two thin corky wings.

+RED OR SLIPPERY ELM+ _Ulmus rubra_ Muhl.

(_Ulmus fulva_ Michx.)

THE red elm, or slippery elm, is a common tree in all sections of the State. It is found princ.i.p.ally on the banks of streams and on low hillsides in rich soil. It is a tree of small to moderate size, but noticeably wide-spreading. It is usually less than 50 feet in height and 16 inches in diameter although trees of larger dimensions are occasionally found.

[Ill.u.s.tration: SLIPPERY ELM

Twig, one-half natural size. Leaf, one-half natural size.]

The _bark_ on the trunk is frequently one inch thick, dark grayish-brown, and broken by shallow fissures into flat ridges. The inner bark is used to some extent for medical purposes, as it is fragrant and when chewed, affords a slippery, mucilaginous substance, whence the tree gets its name. The _winter buds_ are large and conspicuously rusty-hairy.

The _leaves_ are simple, alternate on the stem, 4 to 6 inches in length, sharp pointed, their bases unsymmetrical, doubly-toothed on the edges, thick, dark green, and rough on both sides.

The _fruit_ consists of a seed surrounded by a thin, broad, greenish wing, about one-half an inch in diameter; the _flowers_ appear in early spring and the fruit ripens when the leaves are about half-grown.

The _wood_ is close-grained, tough, strong, heavy, hard, moderately durable in contact with the soil. It is used for fence posts, crossties, agricultural implements, ribs for small boats and for some other purposes.

The water elm, _Planera aquatica_ Gmel., is a small tree with slender branches forming a low broad head and is found in swamps in the valley of the Wabash River in this State. It reaches its best development in Arkansas and Louisiana. It has dull green leaves 2 inches long and 1 inch wide. The fruit is an oblong, dark brown drupe.