American Forest Trees Part 31

The elms are not indispensable woods in this country, but their exhaustion, should it ever come, will leave many places hard to fill. As far as known, no woodlots of any species of elm have been planted in this country, and there is little prospect that any will be planted, because the slow growth of the trees discourages foresters. A century or two is a long look ahead.

However, the exhaustion of no species of the elms in this country need be expected soon. The most apparent peril lies ahead of cork elm, because it never was abundant, and demand, which has been large for a long time, is still strong. The species is scattered over more than 200,000 square miles, and a long time must elapse before the last cork elm finds its way to the sawmill. The situation of white elm is more promising. It may be among the last trees of the American forests to take its final departure. Its wide range and its bounteous seed crops insure a supply, though not necessarily a large one, for a long time.

The greatest peril to elms, as well as to many other forest trees, is that, when weakened by depletion, some disease will attack them and destroy the remnants. Experience in New England and elsewhere has shown that elm has no great resisting power when a strong attack is made upon it.

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SLIPPERY ELM

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SLIPPERY ELM

(_Ulmus p.u.b.escens_)

This tree is known as slippery elm in every state where it grows, thirty or more; but in some localities it has other names also. It is doubtful if any person who is acquainted with the tree would fail to recognize it by the name slippery elm, though some who are acquainted with the lumber only might not know it by that name. Those who call it red elm have in mind the color of the heartwood which is of deeper red than the wood of any other elm, or they may refer to the tawny p.u.b.escence on the young shoots in winter. The botanical name describes that characteristic.

In the North, the slippery elm is sometimes known as moose elm. It furnishes forage in winter for the moose and other herbivorous animals when ground plants are covered with snow. The moose is able to eat branches as thick as a man's thumb. The princ.i.p.al food element in the twigs is the mucilaginous inner bark. It is this which gives the tree its name slippery elm. The value of the bark as a food has been questioned. It is agreeable to the taste of both man and beast, but it is claimed that a human being will starve to death on it, though it will prolong life several days. The lower animals, however, seem able to derive more benefit from eating the bark. An incident of the War of 1812 appears to prove this. The army under General Harrison, operating in the vicinity of Lake Erie, kept the horses of the expedition alive by feeding them on slippery elm bark, stripped from the trees and chopped in small bits.

The inner bark has long been used for medicinal purposes. It is now ground fine and is kept for sale in drug stores, but formerly it was a household remedy which most families in the country provided and kept in store along with catnip, mandrake, sage, dogwood blossoms, and other rural remedies which were depended upon to rout diseases in the days when physicians were few. The slippery elm bark was peeled from the tree in long strips, the rough outer layers were shaved off, leaving the mucilaginous inner layer. That was from an eighth to a quarter of an inch thick. It was dried and put away for use. When needed it was pounded to a pulp, moistened with water, and applied as a poultice, if an external remedy was wanted. If a medicine was needed, a decoction was drunk as tea. There is no question that the remedy often produced good results when no doctor was within reach. A well-known medical writer said three-quarters of a century ago that the slippery elm tree was worth its weight in gold.

The range of slippery elm extends from the lower St. Lawrence river through Canada to North Dakota. It is found in Texas as far west as the San Antonio river, and its western limit is generally from 200 to 300 miles west of the Mississippi river. Its range extends south nearly to the Gulf of Mexico. It is not this tree's habit to grow in thick stands, but it occurs singly or in small groups on the banks of streams or on rich hillsides.

The average size is scarcely half that of white elm. Few trees exceed a height of seventy feet and a diameter of two. It grows rapidly at first, but does not live to old age. The crown lacks the symmetry and beauty so conspicuous in white elm. The limbs follow no law of regularity, but leave the trunk at haphazard. The fruit is mature before the leaves are half grown. The seeds have more wing area than those of white elm; and, like those of white elm, the wing surrounds the flat seed on all its edges. The leaves are rough to the touch, and when crumpled in the hand, the crunching sensation is unpleasant.

Next to white elm, slippery elm appears to be more abundant than any other member of the group; but statistics do not give the basis for close estimates. The factories of Michigan use 3,700,000 feet of slippery elm a year, and 44,000,000 of white elm. The proportion of slippery to white is larger in the factories of Illinois.

The uses are the same as for other elms. The wood is rated more durable than the others, but it is not in much demand for outdoor work where resistance to decay is an important consideration. It is sometimes set for fence posts, but the results are scarcely satisfactory, particularly for round posts which are largely sapwood. Posts sawed from the heartwood of large trees would do better. The deeper red of the heartwood gives it an advantage over the other elms for furniture and finish where natural colors are shown; but this is not important because no elm's natural color stands for much in the estimation of users of fine woods. The more common use of slippery elm is for boxes and cooperage. Next to red gum, it is employed in larger quant.i.ties for cooperage in Illinois than any other wood.

The supply is rapidly decreasing. The cut for lumber is the chief drain, but a not inconsiderable one is the peeling of trees for bark. This goes on all over the species' range and much of it is done by boys with knives and hatchets. It is often hard to find slippery elms within miles of a town, because all have succ.u.mbed to bark hunters.

CEDAR ELM (_Ulmus cra.s.sifolia_) appears to bear this name because it is often found a.s.sociated with red cedars on the dry limestone hills of Texas. There is little in the form and appearance of the tree to suggest the tall, tapering conical crown of cedar. There is still less in the wood. In some parts of Texas the species is called red elm, on account of the color of the wood, while in Arkansas, which is near the northern boundary of its range, it is locally known as basket elm, because basket makers find desirable qualities in its wood. It is a species of rather limited range, but it is abundant in certain regions. It is found as far east as Sunflower river, Mississippi, north into Arkansas, west to Pecos river, Texas, and south into Mexico. It is confined to three states, this side the Rio Grande. Trees on dry hills are inclined to be shrubby, but in damp valleys where soil is fertile, specimens attain a height of eighty feet and a diameter of three, but the average is not nearly so large. The leaves are small but numerous. The flowering habits of this elm are somewhat erratic. The usual time for bloom to appear is August, and a month or six weeks afterwards the small seeds are ready for flight; but occasionally, as if not satisfied with its first effort, the tree blooms again in October, and ripens a second crop late in the fall. The seeds are poorly supplied with wings, which are reduced to narrow margins surrounding the seed. It does not appear, however, that the species is in any way handicapped in securing reproduction. The small shoots are equipped with flat, corky keels, similar to but much smaller than those of the wing elm.

This tree is important for the lumber it produces. It is the common and most abundant elm of Texas, and it is found in a large part of that state. The wood is the weakest of the elms, and is likewise quite brittle; but in the region where it is most abundant it compares favorably with any other. The best is cut from the largest trees, which grow in valleys where moisture is abundant. The growth found on the dry hills is of poor quality, and is worth little, even for fuel. The highest development in Texas, and also the highest in the species' range, is in the valleys of Trinity and Guadalupe rivers. In Texas this wood is employed in furniture factories as inside frames, to be covered by other woods, but it is not employed as outside parts of furniture, unless in very cheap kinds. It is suitable for drain boards and floors of refrigerators where it is wet much of the time. Under such circ.u.mstances it is more easily kept clean than most other woods. It whitens with repeated scrubbings. One of its most common uses in Texas is for wagon hubs.

Some wheelwrights p.r.o.nounce it next to the best native wood for that purpose, the first place being accorded Osage orange. The tree is often planted for shade along the streets of Texas towns, and develops thick crowns and satisfactory forms.

RED ELM (_Ulmus serotina_) is a lately discovered member of the elm family. It so closely resembles the cork elm that it was supposed to be of the same species, and the close scrutiny of a botanist was required to discover that it was a separate species. Sargent observed the flowers opening in September while those of cork elm appear in early spring. The seeds ripen in November, while cork elm's are ripe early in the summer. The tree was named red elm, the wood being reddish-brown. That name is widely applied to slippery elm, but it is improbable that much confusion will result. The red elm's range is quite restricted and in that area the slippery elm is not important. Red elm occurs on limestone hills and river banks from central Kentucky to northern Georgia and Alabama. It attains a height of fifty or sixty feet and a diameter of two or three. The leaves are from two to four inches in length, and one or two wide, with margins toothed like the other elms. The midrib is yellow, and in the autumn the leaves change to an orange yellow before falling.

Branches which are two or three years old develop corky wings, two or three in number.

It is not known that mechanical tests of the wood have been made in a regular way to determine its physical properties, but superficial examination indicates that it is hard, tough, and strong, apparently about the same as cork elm. Special lists of uses for this wood have not been compiled for the reason that lumbermen and operators of sawmills have never distinguished it from other elms of the region.

Since it has never been left standing in districts where other elms are cut, it is evident that it has been regularly put to use for vehicles, agricultural implements, boxes, crates, and slack cooperage, because such articles have been manufactured in the region. The red elm has been occasionally planted as a shade tree along streets of towns in northern Georgia and Alabama.

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PLANERTREE

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PLANERTREE

(_Planera Aquatica_)

This tree is a first cousin of the elms, but it is no more an elm than a hackberry is an elm. It is a member of the family but is of a different genus, and it is the sole representative of its genus in the known world. There is only one kind of planertree, with no nearer relatives than the elms on one side and hackberry, sugarberry, and palo blanco on the other. Except those kinsfolk, it is alone on earth. The name is in honor of Johann Jacob Planer, a German botanist whose efforts did much for science nearly two hundred years ago. The name of the species _aquatica_, recognizes the tree's habit of growing where water is abundant. It is a swamp species, or rather, it prefers situations subject to periodic overflow. It looks like an elm, and that has led people to call it water elm. That is the name by which it is usually known in Florida. In Alabama it is called the American planertree, which is an unnecessary restriction, since there is no planertree except this one. The Louisiana French gave it the name plene, and the abridgement of its name is yet heard in that state. In North Carolina it has acquired the name sycamore, but without good reason. It does not look in the least like sycamore.

It has the leaf of an elm, and it resembles that tree in bark, and somewhat in general form. The layman detects the first important difference when he examines the seeds. Those of the elms have wings, but the planertree's are without those appendages, and they would be useless if it had them, unless they were as large as the parachute of the ba.s.swood seed. The planertree bears a sort of nut, a third of an inch long, and too heavy to be transported far on the ordinary membranous wings of tree seeds. Water is doubtless the princ.i.p.al agent in carrying the seeds from place to place. Probably few of them are transported far, because the water about the trees is generally stagnant; and, besides, the species does not seem to be extending its range or increasing in numbers.

The planertree has a history. If the terms which the Roman historian Tacitus applied to people, could be applied to trees, it might be said of this species, as he said of certain tribes: "The cowards fly the farthest and are the last survivors." The planertree is now found only in certain southern swamps, from North Carolina to Florida, and west to Missouri and Texas. In former periods, as is shown by the records of geology, there were several species, and they had a wide range over portions of the northern hemisphere. They appear to have been a strong group of trees, able to hold their ground with the best inhabitants of the forest. They were in the Rocky Mountains, and far north in Alaska.

They were in Europe also, or were represented there by some very similar species.

For some reason which is not definitely known, they lost out when compet.i.tion with other trees became keen, and in the course of long periods of time they disappeared from their former ranges in the North and West. They took to the swamps, just as the tribes of which Tacitus spoke, took to the mora.s.ses when they could no longer face their enemies on open ground. It was a far cry from Alaska to the Chattahoochee swamps in Florida, yet that was where A. H. Curtis and Charles Mohr went to procure typical planertree specimens for the tests which Sargent made of American woods.

It has been suggested that tree species which have lost out in compet.i.tion for ground, have been those which were at some decided disadvantage in the matter of getting their seeds properly scattered and planted. The case has not been proved, because there are as many facts and as much argument against that hypothesis as for it. The bigtrees of California are a noted example of a species which lost out and retreated to a corner, yet their seeds fly like birds. Plainly, something besides winged seeds is needed to keep the species in the fight. However, it is not difficult to see that the planertree, with wingless seeds and of so little use as food that no bird or rodent will carry them or bury them, has been much handicapped in the long contest which has crowded it from the arctic circle to the cotton belt.

It has the habits of the subdued and conquered tree. It has adapted itself to swamps where few species can grow, and where compet.i.tion for light and room is reduced to a minimum. Yet, even there, it is content to take the leavings of more ambitious species. The crowns make little effort to rise up to the light, for which many other trees battle during their whole existence. The planertree's low, broad top of contorted branches places it perpetually in the shade of any other trees which overtop it.

The wood of the planertree is lighter in weight, poorer in fuel value, weaker, and more brittle than the poorest of the elms. The annual ring lacks the rows of large open pores common in all the elms, but it has many small pores scattered through the whole year's growth. It is not easy to note a difference between the springwood and that which grows later. The wood is soft, light brown in color, and the nearly white sapwood is thick. It is often, perhaps generally, a tree of fairly rapid growth, and since it does not reach large size, it is probably short-lived, but exact information along that line is lacking.

The tallest trees seldom exceed a height of forty feet and a diameter of two. It is evident that a tree of that size and form does not tempt the lumberman to much exertion to procure it. An examination of reports of sawmill operations and of the utilization of woods by shops and factories in the southern states has failed to find a single instance where the planertree has been reported in use for any purpose whatever.

Doubtless, trees are sometimes cut and the lumber gets into the market, but not under its own name. The species is interesting for reasons other than that it ever has had or ever can have a place in the country's lumber industry.

WING ELM (_Ulmus alata_), which is the smallest of the elms, is plentifully supplied with names, but in most parts of its range it is known as wing or winged elm. It is also called wahoo or wahoo elm, and the West Virginians have named it witch elm; the North Carolinans refer to it often as simply elm; from Florida to Texas some call it cork elm; in Alabama it is water elm; in Arkansas mountain elm; while in other regions it is corky elm, small-leaf elm, and red elm. Some of these names are self-explanatory. Wing elm does not relate to a winged seed, but to winged twigs. That characteristic of the tree is very prominent. The wings consist of flattened keels along opposite sides of the branches. A twig no more than a quarter of an inch in diameter may be decorated with wings half an inch or more wide, making the twig four or five times as wide as it is thick. As the twig enlarges, the wings do not broaden in proportion. The lowest branches and those nearest the trunk are most generously furnished with wings. They appear to be entirely ornamental, for it is not known that they serve any useful purpose.

The growth is different from those which give cork elm its name. The latter occur on the large branches, often in the form of isolated protuberances, but the wings are fairly continuous for a foot or more, except that they terminate abruptly at the nodes, but recommence immediately after. Branches less than a year old seldom have wings. The name wahoo appears to have lost its etymology if it ever had any. Dictionaries tell what it means, but they shy at its origin. It is a southern word which is applied to this elm, and also to other trees, and occasionally it means a fish instead of a tree.

Some would trace it to the cry of an owl, others to a name in Gulliver's Travels, with a slight change in spelling.

Wing elm at its best is about fifty feet high and two in diameter; but much of the stand is small. The best occurs west of the Mississippi river. The range extends from Texas to Virginia, south to Florida, and north to Illinois. In Texas it is a fairly important wood in furniture factories, the annual supply being about a million feet. It is used by turners for table legs. In an investigation of the uses of the wood, the same difficulty is encountered that makes difficult a study of the uses of all the elms--conflict and uncertainty of names. There are few regions in the hardwood areas of this country which produce one elm and no more; and after all practical means of identification are resorted to, there is often doubt and uncertainty concerning the exact species of elm lumber found in use. Fortunately, it generally makes little difference, because anyone of them is good enough for ordinary use. Wing elm is extensively planted for shade along the streets of towns in the lower Mississippi valley, but more frequently on the west side of the valley. When the trees grow in the open they develop broad crowns, and the branches, even of comparatively small trees, are long enough to reach well over the sidewalks, and cast satisfactory shade. The dark-colored winged twigs add much to the ornamental value of the street trees.

FREMONTIA (_Fremontodendron californic.u.m_) is not botanically in the elm family, but it is popularly known as slippery elm in the region where it occurs, and for that reason it is here given place among the elms. It is known also as leatherwood. It is a California species, ranging among the lower mountains and higher foothills in dry, gravelly soils, from the Mexican boundary five hundred miles northward in the state. The mucilaginous inner bark tastes like that of the true slippery elm. The shape of the leaf much more resembles sycamore than elm; and it is an evergreen. It bears a bright yellow, roselike flower, and the seeds are small, reddish-brown. The wood is fine grained, clear reddish-brown, with thick, whitish sapwood. It is very soft. The tree attains its largest size among the foothills of the Sierra Nevada mountains, but even there it is too small to have much economic value, seldom exceeding thirty feet in height and a foot in diameter. Its most important use is as a forage plant for cattle and sheep. In that particular it resembles slippery elm in northern woods. The tree is occasionally planted in the eastern states and in Europe for ornament. In its native range it grows slowly.

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HACKBERRY