[Ill.u.s.tration: FIG. 56.--Bark of the Hackberry.]
Commercial value: The wood is strong, close-grained, and tough. It is used mainly for cooperage, tool handles, shoe lasts, chairs, etc., and for fuel.
Other characters: The _fruit_ is a p.r.i.c.kly burr encasing a sharply triangular nut which is sweet and edible.
Comparisons: The _European beech_ (_f.a.gus sylvatica_), and its weeping, purple-leaved, and fern-leaved varieties, are frequently met with in parks and may be told from the native species by its darker bark.
The weeping form may, of course, be told readily by its drooping branches. The leaves of the European beeches are broader and less serrated than those of the American beech.
BLUE BEECH OR HORNBEAM (_Carpinus caroliniana_)
Distinguishing characters: The *fluted* or muscular effect of its *trunk* will distinguish the tree at a glance, Fig. 54.
Leaf: Doubly serrated; otherwise the same as that of ironwood.
Form and size: A low-spreading tree with branches arching out at various angles, forming a flattened head with a fine, slender spray.
Range: Very common in the eastern United States.
Soil and location: Grows in low wet woods.
Enemies: None of importance.
Value for planting: Its artistic branching and curious trunk give the tree an important place in park planting.
Commercial value: None.
Other characters: The bark is smooth and bluish gray in color.
Comparisons: The blue beech or hornbeam is often confused with the _ironwood_ or _hop hornbeam_ (_Ostrya virginiana_). The ironwood, however, has a characteristic bark that peels in perpendicular, short, thin segments, often loose at the ends. See Fig. 55. This is entirely different from the close, smooth, and fluted bark of the blue beech. The color of the bark in the ironwood is brownish, while that of the blue beech is bluish-gray. The buds of the ironwood are greenish with brown tips, while the bud of the blue beech shows no green whatever.
HACKBERRY (_Celtis occidentalis_)
Distinguishing characters: The tree may be told readily from other trees by the *corky tubercles* on the bark of the lower portion of the trunk. See Fig. 56.
Leaf: Has three predominating veins and is a bit more developed on one side than on the other.
Form and size: A small or medium-sized tree with a single stem and broad conical crown.
Range: United States and Canada.
Soil and location: Grows naturally in fertile soils, but will adapt itself to almost sterile soils as well.
Enemies: The hackberry is usually free from disease, though often its leaves are covered with insect galls.
Value for planting: It is extensively planted as a shade tree in the Middle West, and is frequently seen as an ornamental tree in the East.
Commercial value: It has little economic value except for fuel.
Other characters: The _fruit_ is berry-like, with a hard pit. The fleshy outer part is sweet.
Other common names: _Nettle tree_; _sugarberry_.
GROUP VIII. THE OAKS AND CHESTNUT
How to tell them from other trees: The oaks are rather difficult to identify and, in studying them it will often be necessary to look for more than one distinguishing character. The oaks differ from other trees in bearing _acorns_. Their _leaves_ have many lobes and their upper lateral _buds_ cl.u.s.ter at the top of the twigs. The general contour of each oak presents a characteristic branching and st.u.r.diness uncommon in other trees.
The chestnut differs from other trees in bearing _burs_ and its _bark_ is also distinctly characteristic.
How to tell them from each other: There are two groups of oaks, the _white oak_ and the _black oak_. The white oaks mature their acorns in one year and, therefore, only acorns of the same year can be found on trees of this group. The black oaks take two years in which to mature their acorns and, therefore, young acorns of the present year and mature acorns of the previous year may be found on the same tree at one time. The _leaves_ of the white oaks have rounded margins and rounded lobes as in Fig. 57, while those of the black oaks have pointed margins and sharp pointed lobes as shown in Figs.
60, 62 and 64. The _bark_ of the white oaks is light colored and breaks up in loose flakes as in Fig. 58, while that of the black oaks is darker and deeply ridged or tight as in Figs. 59 and 61. The white oak is the type of the white oak group and the black, red and pin oaks are types of the other. For the characterization of the individual species, the reader is referred to the following pages.
[Ill.u.s.tration: FIG. 57.--Leaf and Fruit of White Oak. (Quercus alba.)]
WHITE OAK (_Quercus alba_)
Distinguishing characters: The ma.s.sive ramification of its branches is characteristic of this species and often an easy clue to its identification. The *bark* has a *light gray color*--lighter than that of the other oaks--and breaks into soft, loose flakes as in Fig. 58. The *leaves are deeply lobed* as in Fig. 57. The *buds are small, round and congested* at the end of the year"s growth. The acorns usually have no stalks and are set in shallow, rough cups.
The kernels of the acorns are white and palatable.
Form and size: The white oak grows into a large tree with a wide-spreading, ma.s.sive crown, dissolving into long, heavy, twisted branches. When grown in the open it possesses a short st.u.r.dy trunk; in the forest its trunk is tall and stout.
Range: Eastern North America.
[Ill.u.s.tration: FIG. 58.--Bark of White Oak. (Quercus alba.)]
Soil and location: The white oak thrives in almost any well-drained, good, deep soil except in a very cold and wet soil. It requires plenty of light and attains great age.
Enemies: The tree is comparatively free from insects and disease except in districts where the Gipsy moth is common, in which case the leaves of the white oak are a favorite food of its caterpillars.
[Ill.u.s.tration: FIG. 59.--Bark of Black Oak. (Quercus velutina).]
Value for planting: The white oak is one of the most stately trees. Its ma.s.sive form and its longevity make the tree suitable for both lawn and woodland planting but it is not used much because it is difficult to transplant and grows rather slowly.
Commercial value: The wood is of great economic importance. It is heavy, hard, strong and durable and is used in cooperage, construction work, interior finish of buildings and for railroad ties, furniture, agricultural implements and fuel.
Comparisons: The _swamp white oak_ (_Quercus platanoides_) is similar to the white oak in general appearance of the bark and form and is therefore liable to be confused with it. It differs from the white oak, however, in possessing a more straggly habit and in the fact that the bark on the under side of its branches s.h.a.gs in loose, large scales. Its buds are smaller, lighter colored and more downy and its acorns are more pointed and with cups more shallow than those of the white oak. The tree also grows in moister ground, generally bordering swamps.
[Ill.u.s.tration: FIG. 60.--Leaf and Fruit of Black Oak. (Quercus velutina).]
BLACK OAK (_Quercus velutina_)
Distinguishing characters: The *bark* is black, rough and cut up into firm *ridges* especially at the base of the tree, see Fig. 59. The _inner bark_ has a _bright yellow color_: the *leaves* have _sharp points_ and are wider at the base than at the tip as shown in Fig.
60. The buds are _large, downy_ and _sharp pointed_. The acorns are small and have deep, scaly cups the inner margins of which are downy. The kernels are yellow and bitter.