BOX ELDER
(Acer Negundo)
Attempts to ascertain the meaning of the word negundo which botanists apply to this species have not been crowned with entire success. It is known to be a word in the Malayalam language of the Malabar coast of India, and is there applied to a tree, apparently referring to a peculiar form of leaf. The name was transferred to the box elder by Moench, and has been generally adopted by botanists, although at least seven other scientific names have been given the tree. It bears ten or more English names in different regions. Among these names are ash-leaved maple, known from Massachusetts to Montana and Texas; cut-leaved maple in Colorado; three-leaved maple in Pennsylvania; black ash in Tennessee; stinking ash in South Carolina; sugar ash in Florida; water ash in the Dakotas; and box elder wherever it grows.
The tree’s geographical range does not fall much short of 3,000,000 square miles, and is equalled by few species of this country. It extends from New England across Canada to Alberta, thence to Arizona, and includes practically all the United States east and south of those lines. It thrives in hot and cold climates, and high and low elevations; in regions of much rain, and in those with little. That fact has been turned to account by tree planters, particularly in the years when the western plains were being settled by homesteaders. The box elder was the chief tree on many a timber claim where the letter of the law rather than the spirit was carried out. It afforded the earliest protection against scorching summer sun and the keen winds of winter about many a frontiersman’s cabin on the plains. It was the earliest street tree in many western towns. The people planted it because they knew it would grow, and they were not so sure of a good many other trees. Green ash was often its companion in pioneer plantings on the plains. Many towns which set box elders along the streets when they did not know of anything better, still have the trees, though they would willingly exchange them for something else. They are not ideal street and park trees; do not produce shapely trunks and crowns; and drop leaves all summer and seeds all winter. The tree is reputed to be short lived, yet some of those planted a generation or two ago show no symptoms of decline.
There is no good reason why this tree should be called an elder, or an ash, except that its leaves are compound. If that is a reason, it might be called a hickory or a walnut, since they bear compound leaves. It is clearly a maple. Its fruit shows it to be so, and Indians of the far Northwest who had no other maple, formerly manufactured sugar from this tree, collecting the sap in wood or bark troughs and boiling it with hot stones.
The compound leaf does not necessarily take it out of the maple group. It requires no great exercise of imagination to understand how a lobed leaf, by deepening the sinuses between the lobes, might become a compound leaf in the process of evolution. There may be no visible evidence that the box elder’s leaf reached its present form by that process, but there is another maple which is at the present time developing a compound leaf in that way, or seems to be doing so. It is the dwarf maple (Acer glabrum) of the Northwest coast. Lobed leaves and compound leaves may occur on the same tree.
The seeds of box elder resemble those of other maples. They ripen in the fall, and are blown off by wind, few at a time, during several months. The trees are from fifty to seventy feet high, and from one and a half to three feet in diameter. The trunk is apt to divide near the ground in several large branches, and is not of good form for sawlogs, being often crooked as well as short. The small branches, particularly those less than a year old, are usually nearly as green as the leaves. This fact may assist in identifying the tree when the leaves are off. The bark bears more resemblance to ash and basswood than to maple.
The wood is lightest of the maples. It weighs less than twenty-seven pounds to the cubic foot; has less than half the strength and about forty per cent of the stiffness of sugar maple; and is much inferior to it in most mechanical properties. It is equal, if not superior to most maples in whiteness. The pores are small, numerous, and scattered through all parts of the growth ring, as is characteristic of maple wood. The tree grows rapidly. The summerwood is a thin, dark line, separating one annual ring from another. The medullary rays are many and obscure, but when wood is sawed or split along a radial line, they are easily seen, and show the true maple luster.
The uses of box elder are similar to those of soft maple. The wood is seldom reported under its own name. In fact, an examination of wood-using reports of various states, shows that in only two states, Michigan and Texas, has box elder been listed separately. Its uses in the former state were for boxes, crates, flooring, handles, woodenware, and interior finish, while in Texas it was made into furniture. The tree is of commercial size in at least thirty states, and is cut and marketed in all of them. Tests of the wood for pulp are said to be satisfactory, and it finds its way in rather large amounts to cooper shops where it is made into slack barrels. It is cut as acid wood along with other maples, beech, and birch, and is converted into charcoal and other products of distillation.
It may be expected that box elder will exist in the United States as long as any other forest tree remains. It is willing to be crowded off good land into low places, which are almost swamps, and there it grows free from disturbance; but if given the opportunity it will appropriate the most fertile soil within reach of it; and by scattering seeds during four or five months of the year, it manages to do much effective planting.
California Box Elder (Acer negundo californicum) is a variety of box elder, and not a separate species. As the name implies, it is a California tree, and it occurs in the valleys and among the Coast Range mountains from the lower Sacramento valley to the western slopes of the San Bernardino mountains. The tree is from twenty to fifty feet high and from ten to thirty inches in diameter. The leaves and young twigs are hairy, in that respect differing from the eastern box elder. The seeds are scattered during winter. The wood is very pale lemon-yellow or creamy-white, the heart and sapwood hardly distinguishable. The wood is soft and brittle, but is suited to the same purposes as the eastern box elder. No reports of its uses appear to have been made. It is found on the borders of streams and in the bottoms of moist canyons. It is believed to be a short-lived tree.
Striped Maple (Acer pennsylvanicum) is usually thirty or forty feet high, and eight or ten inches in diameter. Its range extends from Quebec to northern Georgia, westward to Minnesota, and is of largest size on the slopes of Big Smoky mountains of Tennessee, and the Blue Ridge in North and South Carolina. It grows best in shade, but maintains itself in open ground; is generally shrubby in the northern part of its range. The name refers to the bark. The stripes are longitudinal and are caused by the parting of the outer bark and the exposure to view of the lighter colored inner layers. The bark of small trees is greenish, but later in life the color is darker, and the stripes largely disappear. Among its names are moosewood, so called because it is good browse for moose and other deer; goosefoot maple, a reference to the form of the leaf; whistlewood, an allusion to the ease with which the bark slips from young branches in spring when boys with jack-knives are on the search for whistle material. The names mountain alder and striped dogwood are based on misunderstanding of the tree’s family relations.
The young leaves are rose colored when they unfold, and when full grown are six inches wide. The wood is light and soft, and light brown in color, the thick sapwood lighter. The wood is liable to contain small brown pith flecks, which in longitudinal sections appear as brown streaks an inch or less in length and as thick as a pin, and in cross section they are brown dots. They are not natural to the wood but are caused by the larvÆ of certain moths which burrow into the cambium layer, or soft inner bark, and excavate narrow galleries up and down the trunk. The galleries afterwards fill with dark material. The insects sometimes attack other maples, the birches, service, and other trees. The wood of striped maple is little used, because of the small size of the trees. The species is planted for ornament in this country and Europe.
Black Maple (Acer nigrum) has been by some considered a variety of sugar or hard maple, and by others a separate species. It is as large as the sugar maple and its range is much the same, but it is more abundant in the western part of its range than in the East. The name refers to the color of the bark of old trunks. If the name had considered the bark of young twigs it would have been yellow or orange maple, because the twigs are of that color. In summer the peculiar drooping posture of the leaves calls attention to this tree. However, the bark, twigs, and leaves combined are not sufficient to set it apart, in the eyes of most people, for it generally passes without question as sugar maple, even when it stands side by side with that tree. It yields sugar abundantly. The wood is a little heavier than that of sugar maple, but the difference cannot be noticed except when the two woods are weighed. Their uses are the same. No maker of furniture, flooring, or finish ever protests against black maple. The tree generally prefers lower and damper ground than sugar maple, and is often found along streams.
Box elder branch
