WHITE ELM
(Ulmus Americana)

Six species of elm occur in the United States, not counting the planer tree as an elm, though lumbermen usually consider it as such.[5] The white elm is the most common, is distributed most widely, and is commercially the most important. More of it is used as lumber, slack cooperage, and other forms of forest products, than all other elms of this country combined. The statistics of sawmill output collected annually by the United States census are not compiled in a way to show the elms separately. All go in as one. The annual lumber cut of elm in the whole country is about 265,000,000 feet, distributed over thirty-four states, with Wisconsin leading, followed in the order named by Michigan, Indiana, Ohio, Missouri, Arkansas, New York, and Minnesota. In addition to lumber, elm furnishes about 130,000,000 slack cooperage staves yearly.

The elms, taken as a class, are much alike. There is more resemblance between the species than between species of oaks or pines, yet some difference exists between elms. This holds not only between different species, but between individuals of the same species. Climate, situation, and soil have much to do with the character of the wood of the same species. So great is the difference at times that fairly good judges of timber are deceived as to the species. A tree growing on dry, rocky soil produces wood quite different from one on rich, deep, well-watered soil. Not only is the wood of one different from that of the other, but the appearances of the standing trees are not alike. The differences may not show in leaves, flowers, and fruit as much as in the shapes and sizes of trees, and the habit of the branches.

White elm is by common consent the type of the genus, the standard by which the other species are measured. It is proper to compare certain properties and characters of other elms with white elm, in order that a general view of all may be had. The dry weights, per cubic foot, of wood are as follows: White elm 40.54 pounds, slippery elm 43.35, cedar elm 45.15, cork elm 45.26, and wing elm 46.69. Figures which show the weight of the southern red elm (Ulmus serotina) are not available. White elm is thus shown to be lightest of the group.

Its breaking strength averages 12,158 pounds per cubic inch, under the usual tests by which the strength of woods is determined. Reduced to everyday language that means that 12,158 pounds would just break a white elm stick, 2⁵/₈ inches square, and resting on supports twelve inches apart. That is the meaning of “breaking strength,” or “modulus of rupture,” as the term is used in engineering text books relating to woods. The following figures for the breaking strength of other elms make comparisons with white elm easy: Cedar elm 11,000; wing elm 11,162; slippery elm 12,342; cork elm (often called rock elm) 15,172. It is shown that two elms are stronger and two weaker than white elm. This wood rates very little below white oak in strength.

The different species of elms vary considerably in stiffness, or the ability to spring back when bent. This factor is expressed by engineers in high figures, is purely technical, and is based on a wood’s ability to stretch and regain its former position. The only service which the figures can render to the layman is to furnish a basis for comparing one wood with another. The stiffer a wood, the greater its resistance to an effort to stretch it lengthwise. White elm’s measure of stiffness (modulus of elasticity) is 1,070,000 pounds per square inch; wing elm 853,000; cedar elm 981,000; slippery elm 1,318,000; cork elm 1,512,000. It is shown here, as was shown in the figures representing the strength of the elms, that two species rate above and two below white elm in stiffness.

White elm is known by several names. The color of the bark is responsible for the name gray elm among lumbermen and woodworkers of the Lake States. American elm is a translation of its botanical name, and is neither descriptive nor definitive, because there are other elms as truly American as this one. White elm distinguishes its wood from the redder wood of slippery elm, but it would often be difficult if not impossible to identify the elms, or any one of them, by the color of the wood alone. Some persons who call this elm white doubtless refer to the color of the bark, as is the case with those who speak of it as gray elm. It is known as water elm in several states, but that name is applied indiscriminately to any elm that frequents river banks, as most of them do in some part of their range. It is called rock elm when it is found on stony uplands, and swamp elm on low wet ground. In some parts of the Appalachian mountain ranges it is called astringent elm to distinguish it from slippery elm.

White elm surpasses the others in extent of range. Its northern boundary stretches from Newfoundland, across Canada to the eastern base of the Rocky Mountains, a distance of nearly 3,000 miles. It runs south through the Atlantic states to Florida, a distance of 1,200 miles or more. Its southwestern limit is in Texas. The area thus bounded is about 2,500,000 square miles. A few other trees have ranges as large, but none much exceed it. It covers so much of America, and is so important in many parts of its range, that it is clearly the leading elm in this country. It is entitled to first place among elms for other reasons.

It is not easy to give any sure features or characteristics by which the layman may always distinguish this elm from others with which it is associated; however, by carefully observing certain features, the identity of white elm is generally easy to establish.

The leaves have teeth along the margins like beech and birch. They have straight primary veins running from the midrib to the points of the teeth. Before falling in autumn the leaves turn yellow. The foliage is not very thick, and most of it is near the ends of the limbs. The bloom comes early in the spring, ahead of the leaves, and the seeds are ripe and ready for flight before the leaves are grown. Sometimes the seeds are ripe almost before the leaves are out of the buds. The seeds are oblong, and about the size of a small lentil. The wing entirely surrounds the seed, and is about half an inch long. The flight of elm seeds is an interesting phenomenon. The individual seeds are so small that they are not easily seen as they sail away from the tall tree top but when they go in swarms, in fitful puffs of wind, they are not hard to see. It is chiefly by their fruits that they are known, that is, by the multitudes of seedlings that appear a few weeks later. If one seedling elm in a thousand should reach maturity, there would be little besides elms in the whole country. They spring up by highways and hedges, in gutters, fields, and even between cobbles and bricks of paved streets; but in a few days they have crowded one another to death, or have perished from other causes, and those which manage to live to maturity do not much more than make up for old trees which perish from natural causes.

The botanist Michaux pronounced the white elm “the most magnificent vegetable of the temperate zone.” A number of trees are larger, though this reaches great size. Sargent sets the limit of the tree at 120 feet high and eleven feet in trunk diameter. That size is, of course, unusual, but it has been surpassed at least in height. A tree in Jefferson county, Pennsylvania, was 140 feet high, and although forest grown, it had a spread of crown of seventy-six feet. It was sent to the sawmill where it made 8,820 feet of lumber. That trunk was only five feet in diameter.

Some of the finest forest grown elms in this country have been cut in Michigan. Their trunks were as tall, straight, and shapely as yellow poplars, and their crowns surpassed those of poplars. It was formerly not unusual for sawlogs to be cut from elm limbs which branched from the trunk fifty or more feet from the ground. The best of the forest grown elm of this country has been cut; but it is still lumbered throughout the whole eastern half of the United States.

The finest elms of this country, and doubtless the finest in the world, are the planted trees in some of the New England villages. The largest of them have been growing for two hundred years, and in many instances they still show the vigor of youth. Trunks six or seven feet through are not uncommon, but the glory of the trees is not alone in the trunks. Their spread and form of crown are magnificent. The largest are 150 feet across, and some of the splendid branches, rising in parabolic curves, are fully 100 feet long, from the junction with the tree to the tips of the twigs. The most apt comparison for that form of elm is the spray of a fountain. The upward jet of water corresponds to the trunk of the tree; the upward, outward, and downward curves of the spray represent the crown of the elm. Trees which take that form are grown in open ground where sunlight and air reach every side. Forest grown trees are less symmetrical, but even in dense woods, the elm frequently rises clear above the canopy of other trees, and develops the fountain form of crown. The new England street and park elms surpass those farther west only because they are older. The splendid trunks and crowns are the work of centuries.