Trees.
—Apple.—A rather good-looking tree with a beautiful show of blossoms in the spring. Used extensively as a road tree in Europe. The native crab-apple and the thorn-apple (red haw) are both fine for their blossoms. They do not grow large so can be used in group planting.
Arbor vitae.—A species of cedar used for screens, wind-breaks, and hedges, and for filling in shrubbery where a variety of color is desired.
Ash.—There are some half dozen or more varieties found native in the United States covering a region from the Atlantic to the Rockies and extending into Oregon and Washington. Nearly all of them are suitable for road and street trees. In parks they are good for massing as they stand close planting.
Aspen.—A species of poplar, rapid growing and often springs up in the pine forests after the conifers have been cut off. The color of the leaves makes it desirable in some plantings. Will grow in close masses.
Balm of Gilead.—A species of poplar (black cottonwood); a good-looking tree but like other poplars not especially desirable as a road tree, but in all the Northern states where quick growth is wanted might be used.
Bamboo.—Native of South Sea Island, Philippines, southern Asia, other southern countries and a species in Florida. A rapid growing plant, quite graceful, and can be utilized for group and massive planting where acclimated.
Basswood.—See [Linden].
Bay.—See [Laurel].
Beech.—A beautiful tree both in summer and winter. Best when grown individually. There are fifteen or more species belonging to the genus (Fagus). The blue beech or ironwood, a rather small tree, may be used where its peculiar color is desired.
Birch.—Some twenty-four species are known in the United States, inhabiting mostly the northern part, extending into Canada and Alaska. The birches, especially the paper or white birch, are distinguished by their light-colored bark. That of the white birch was used by the Indians for canoes. It is an excellent park tree if it can be saved from being peeled by the ubiquitous vandal.
Box Elder.—A species of maple found quite generally from the Atlantic Ocean to the Rocky Mountains. It grows to a height of approximately fifty feet with a spread about the same. It casts a dense shade and since it will stand severe climatic changes is a good tree for the naturally treeless sections. Has been used much as a street tree, although not particularly shapely as to trunk.
Buckeye.—The buckeye and horse chestnut are species of the same genus. To the native species is usually given the name buckeye. The Ohio buckeye is from 30 to 45 feet in height and is useful in mass planting and not at its best in road planting.
PIN OAK STREET TREES
About 15 Years Old on Land that Was Once Considered to be a part of the “Great American Desert.”
A COTTONWOOD WIND BREAK
Formerly very Common in the Prairie Region.
Camphor.—The Camphor Tree (Cinnamomum camphora) is quite commonly planted for street trees in the Southeastern, Southern and the Southwestern states. The tree is a thrifty grower and is nice and straight. The leaves and wood have the characteristic aromatic camphor odor, and from them can be extracted the juice. Another tree of the same genus C. zeylanicum has also been imported from Asia and may be found in the same states. From the roots is obtained cassia bark.
Catalpa.—Was planted extensively a few years ago because it was thought it would quickly develop timber large enough for fence posts and ties in a few years. The best variety is the Catalpa speciosa, which grows under favorable conditions to a height of 60 feet, with a spread of 30 feet. The leaves are large and of good color, but slow to appear in the spring and drop at the first frost in the fall. The flowers are very showy. For this reason, its general shapely appearance, and its rapid growth, it is a good road tree. It does not seem to be very long lived, and as a street tree it is objected to by those having close cropped lawns because of its bad habit of shedding its long seed pods all summer.
Cedar.—There are many species of cedars, both red and white. The arbor vitae has already been mentioned. Juniperus virginiana is perhaps the best road tree. It grows from 50 to 80 feet tall with a spread of one-quarter to one-third its height. It is suitable in nearly every place where evergreens can be utilized. Its pyramidal shape makes it well adapted to formal landscape architecture and hence would make a good road tree for avenue planting.
Citrus Fruit.—Orange, lemon, grapefruit, and citron are freely planted in Florida and California. Where these come up to the highway they answer for road trees. The citrus trees have a beautiful dark green shiny foliage with a round top, and with their flowers and ripening fruit are always interesting.
Coffee Tree.—A good lawn or park tree, but a very few specimens will be sufficient.
Cherry.—The wild cherry, Prunus serotina, also called black-cherry, grows native over much of the eastern and central portions of the United States. It is the tree from which the cherry wood is obtained. It is hardy, grows to a good height, 40 to 80 feet, with a spread of 20 to 40 feet. It is a good road tree spoken of by one writer as “charmingly unconventional,” and bears a slightly bitter pea-sized fruit of which the birds are fond. It is deserving of larger planting as a road and street tree. The chokecherry is a much smaller tree, from 5 to 20 feet high and can be used in massing and screening. The blossoms in the spring and a little later the fruit of which birds are extremely fond, make it worthy of attention. The Japanese flowering cherry and tame cherries are sometimes used for their blossoms.
Cottonwood.—A species of poplar found native from Maine to Florida and westward to the Rocky Mountains. Being so hardy and a rapid growing tree, it was planted freely by the early settlers in the plains regions of the Mid-west. A variety known as Carolina poplar grows especially straight and tall, from 75 to 100 feet, with a spread of 25 to 30 feet. The cottonwood is not strong and is liable to be broken in the wind, because of this fact old trees are usually more or less unsightly. The shedding of cotton from the pistilate tree is objected to, but this trouble may be avoided by propagating only from staminate trees by cuttings. Nevertheless it is a valuable tree where rapid growth and quick shade is desired.
Chestnut.—The chestnut (Castania vulgarus) and one or two other species was formerly an important timber tree in the Eastern states. The tree when not in foliage looks something like red oak. It grows to a height of 75 to 100 feet, 5 to 12 feet in diameter. In Europe a chestnut is mentioned 204 feet in circumference. The spread of the tree is from one-fourth to one-half its height. The nuts are edible. A bark disease has carried off most of the Eastern trees, and the larvæ of insects almost universally infect the nuts. However, it is a rapid grower and might be worth planting where it is known to thrive.
Cucumber Tree.—A large, handsome tree, symmetrical, 50 to 75 feet in height of the magnolia family, its fruit resembling cucumbers. It is a native of the Eastern states.
Cypress.—The bald cypress, though a large tree and of commercial importance, has little value as a road tree because it grows in swamps, the very worst place for a road. It might be utilized in the lake of a park.
Dogwood.—A native shrub of several varieties. Its low growing tendencies, its beautiful flowers and showy fruit make it a valuable ornamental shrub for parks. A species Cornus Florida grows into a tree some 25 feet high.
Douglas Spruce or Fir.—Snow[213] states this (Pseudotsuga) genus “is neither a true pine, spruce, nor fir, but a sort of bastard hemlock. The name ‘pseudotsuga’ is from pseudo, or false, and tsuga or hemlock.” These trees are among the largest known and the wonder of the traveler through the forests of Oregon and Washington. Along the lines of these roads it were well, if the pleasure of the tourist be of import, to retain the most beautiful specimens. It grows from 175 to sometimes 300 feet in height, and 3 to 5, and sometimes 10 feet in diameter.
Elm.—The American elm (Ulmus americana) is considered by many to be the best street and road tree in this country. It has a large rounded top with long graceful branches. The shade is not very dense and the lack of foliage near the ground allows the free circulation of air. It grows into an exceptionally fine individual specimen and will also group well. The general good appearance of the tree both in summer and in winter makes it a favorite. There are some fifteen different species of elm distributed over the temperate portions of the Northern Hemisphere, except along the western coast of North America. The wood being tough and fibrous it withstands damage from the wind fairly well. Occasionally the long branches become so heavy they break down, but usually the tree is so well balanced that it stands up well. The white or American elm is the favorite for road work. The red or slippery elm (U. pubescens) is a beautiful tree and would be used more frequently in road and park work were it not that its delectable mucilaginous inner-bark makes it the mark of the road vandal. White elm grows from 90 to 100 feet in height with a spread of 50 to 75 feet. There is a tree now being featured by the nurseries called English elm which has a smooth bark and very shapely appearance. The cork elm (U. racemosa), grows from 75 to 90 feet in height, best developed in southern Ontario and Michigan, with a somewhat rough shaggy bark, is also a good road tree.
Eucalyptus.—This genus includes about 400 species. They are variously and locally known as gum trees, stringy-barks, iron-barks, mahoganies, and box, and are natives of Australia and neighboring islands. They have been widely planted throughout the world in warm climates. The blue gum (Eucalyptus globulus) does well at least as far north as Sacramento, and has practically changed the landscape of Southern California and Arizona. The tree has an extremely rapid growth, reaching a height of 200 and sometimes 300 feet. Some of the trees have a shaggy exfoliating bark while others seem smooth. The leaves of the young tree in some of the species, very noticeable in the blue gum, change their form and color as the tree reaches a certain age. Likewise the color and shape of the leaves and flowers differ widely with different species. They all are “evergreen” but the leathery leaves are blue, gray, or green. The leaves of the blue gum are blue, oval, and stalkless when the tree is young while the leaves of the older trees have stems, are dark green, some 10 or 12 inches long, an inch wide, and sickle shaped. In southern California they have been known to grow 25 feet in one year. The various varieties may be used in various ways, some for wind breaks and massing and some for individual specimens. Some are brilliant with flowers during a period of year when other flowers are scarce. Eucalyptus oil extracted from them is used as a medicine. For dry warm climates they make an excellent road tree.
Fir.—There are a large number of species and like other evergreens have their uses in landscape work. They look much like the spruces. In the West many of them grow to tremendous sizes.
Gingko.—A picturesque tree, sometimes called the maiden-hair, has been used about the city of Washington for street purposes. Gingko biloba is a native of Japan. While beautiful it would require much care to get it properly started.
Gum Tree.—The name is applied to trees of diverse species. Sweet gum (Liquidambar styraciflua) grows from Connecticut to Florida, and westward, intermittently to Illinois and Texas. Greatest development in the basin of the Mississippi River. This is a tall, straight tree with symmetrical top, rather smooth bark with corky ridges. A good-looking road tree. The star-shaped leaves turn brilliant scarlet in the fall. The seed pods are a sort of bur or rounded ball. Black, or sour gum, while the wood is difficult to work and does not burn easily, ought to be a fairly successful road tree in some localities. Grows from 45 to 100 feet high.
Hedge.—See [Osage Orange].
Hackberry.—In the Western prairie states has proven itself to be a very good street tree. Grows to a height of about 50 feet with a spread of 30 feet. The bark is corky and deep cut, giving it a rough surface. In general appearance resembles the elm. Deserves more general planting.
Hemlock.—Is found native, in several species, over the northern part of the United States and southern Canada. Frequently found with broad-leaved and other needle-leaved timber. Tsuga canadensis grows from 60 to 80 feet in height, has short leaves, green above and light beneath, a straight trunk and beautiful appearance. Western hemlock is found as high as 6500 feet above sea level.
Hickory.—The several species of this genus are recommended highly for road purposes in the Eastern half of the United States. Probably at its best from Michigan to Missouri. The shagbark (Hicoria ovata) grows to a height of 75 to 90 feet with a spread of half as much. The bark is rough and shaggy—hence the name. It bears fine edible nuts in abundance. It will well repay planting along the roads. Pignut (H. glabra) a fine tree of about the same height has a smooth bark and nuts that are rather bitter and sometimes astringent, but from its fine appearance and useful wood is worthy of planting. Pecan (H. pecan) is especially adaptable to the more southern climates, growing very thriftily in Texas and other Southern states. Reed says,[214] “it is the noblest nut tree of all American species. Beautiful trees, sometimes 3 or 4 feet through at the base and from 100 to 150 feet tall, occur in the alluvial soils of the Mississippi River and its tributaries and in the Southwest. In the Southern states it forms a splendid roadside tree and orchards of it are worth going long distances to see. Very often enough nuts are gathered from a half dozen trees on a city lot to pay the taxes and keep up the insurance on the home.”
Holly.—Occasionally 50 feet in height but more often much smaller, particularly in the North. Occurs from Massachusetts to Texas. The foliage is evergreen and the beautiful red berries remain until spring. Might be utilized in park plantings.
Horse Chestnut.—See [Buckeye].
Juniper.—See [Cedar].
Koelreuteria.—Koelreuteria paniculata is recommended for a park tree for middle ground planting, being a small tree, 15 to 30 feet high, with feathery pinnate leaves and yellow blossoms.
Larch.—The larches are deciduous, needle-leaved conifers. A tall, straight, slender tree. If planted at all should be in groups or masses. The winter aspect is not particularly inviting.
Laurel.—The laurels, known as magnolia trees, Magnolia grandiflora found along the Atlantic as far north as Washington, and Umbellularia californica and Arbutus menziesii found in California, are ornamental trees of the highest rank. They make fine individual specimens reaching a height from 50 to 100 feet and a spread fully half as much. The dark evergreen foliage and large showy flowers give them a most beautiful appearance. A magnolia avenue is certainly worth seeing. Several other varieties of laurel are recommended for planting as far north as New York.
Lemon.—See [Citrus Fruit].
Lignum vitae.—A low gnarled tree grown in semitropical regions. Could be used in picturesque landscape work.
Linden.—Variously called basswood, whitewood, linn, beetree; is found intermittently throughout the eastern half of the United States. It is, when grown, 60 to 90 feet in height and has a spread of 30 to 45 feet. It has large, smooth leaves and in the spring its flowers are very productive of honey. It is quick growing but said to be long lived. The American linden (Tilia americana) is perhaps the most thrifty for a road tree. It can be used individually and deserves more extensive planting.
Locust.—The name locust seems to have been applied to three distinct genera of the family Leguminosae. The black locust (Robinia pseudacia) is a fine appearing tree but in the Middle West is much subject to attack by borers. In other regions it does not seem to suffer that way. It attains a height of 50 to 75 feet, and a spread half as great. The honey locust, a little larger tree, 75 to 90 feet high, with a spread of 30 to 40 feet, is less subject to borer attack, and is one of the hardiest trees for Western Kansas[215] upland planting. The long compound thorns are sometimes objectionable, but these may be avoided by selecting only those specimens having no thorns, for the thorns are frequently absent. As a road tree the honey locust is worthy of much attention. Another genus of locusts is the ordinary mesquite (Prosopis juliflora) of the so-called desert regions. They sometimes grow to 40 or 50 feet in height, sometimes they are a shrub. They are naturally a dry country plant and should be used in places where the moisture is scanty. It is said,[216] “The easily agitated foliage cools the air to a surprising degree.” The “cool shade of the mesquite” is a characteristic phrase. A valuable tree in its own region. The roots furnish wood, the pods are filled with a sweetish pulp from which the Indians, it is said, made “bread, cake, and fermented drink.” “A black dye is obtained from the sap, and a good mucilage from the gum.”
Magnolia.—See [Laurel].
Maple.—One of the best road trees, by some considered superior to Elm. The hard maple (Acer saccharum), the soft maple (Acer saccharinum), are the principal American species of the genus, comprising very many, which grow in the Northern Hemisphere. The Norway maple (Acer platanoides) similar to the hard or sugar maple, has been imported and is used to a considerable extent. The hard maple in New York state and the east is a rapid growing tree; when transplanted to the plains region its growth is very slow. The Norway maple seems to be more rapid, but that too, is slow in those regions. Hard maples grow to 70 or 100 or more feet in height with a spread of nearly the same. When allowed to grow individually and branch from the ground, they form an oval top nearly as wide as high. The shade is dense and the numerous branches in winter and heavy foliage in summer give to the tree a very fine appearance. The leaves turn yellow and scarlet in the fall giving to the woods a most fascinatingly gorgeous aspect. What has been said about the hard maple is true in a lesser extent of soft maples. In the western part of the Mississippi Valley the soft maple is a much more rapid grower. The height attained is not quite so great, 40 to 90 feet. They have when allowed room a fine shape sometimes suggesting elm. The leaves are silvery white beneath, which is why they are sometimes called silver maple. They do not turn so yellow or so red in autumn as the hard maple. On the whole a road tree that may be recommended. The red maple has been mentioned under the name box elder. The Oregon maple (Acer macrophyllum) about the same size as the soft maple is one of the most ornamental broad-leaved trees on the Pacific Coast.
Mulberry.—Red and white, named from the color of the ripe fruit, under good conditions attain a height of 40 to 60 feet, and are quite ornamental. The fruit is sweet, lacking in acid, but is liked by the birds and by some people. A Russian shrub variety is used for low hedges and stands trimming remarkably well.
Oak.—The oaks not only furnish the finest of building lumber but are practically all good ornamental trees. The principal reasons they are not used more are the difficulty of transplanting them and their slow growth. However, they are well worth the trouble and wait. The oaks, of which there are some 300 species, are found native in most of the Northern Hemisphere and in a few places south of the equator. They are usually classified as white oaks, red oaks and live oaks. They are quite easily distinguished by the foliage, bark, and general appearance of the trees, but not easily, always, by the wood. In all cases the fruit is an acorn, an oval or oblongly lanceolate smooth nut having a thin shell and partly enclosed in a scaly woody cup. A dozen or more species could be described as good road and park trees, but a few will suffice. White oak (Quercus alba) is widespread throughout the north central and eastern United States. It rises to 75 or 100 feet in height and spreads nearly as much. It is truly a magnificent tree when grown. The cow oak (Q. michauxii) grows best in a slightly more southern region, is nearly the same size. The chestnut oak (Q. prinus) is slightly smaller, is found along the eastern border, has leaves somewhat resembling a chestnut, and reaches 75 to 80 feet in height. Post oak (Q. minor), still smaller, inhabits the Gulf states. Bur oak (Q. macrocarpa), one of the largest of the oaks, extends farthest west and northwest of the eastern oaks. It is recommended for prairie planting. The red oak, (Q. rubea) best in the Northeastern states, is found native as far west as Nebraska. It is 90 to 100 feet in height, is rather more upright than the white oaks, the spread not so great. The pin oak (Q. palustris) has proven itself well adapted for transplanting. Since it has a straight upright trunk and symmetrical body is a good street and road tree, at least as far west as Nebraska. The live oaks (Q. virginiana), (Q. agrifolia), (Q. chrysotepis) do well in the Southern states and in California. They grow from 50 to 80 feet in height and are evergreen. Q. bicolor, and the scarlet oak, Q. coccinea, are also recommended for landscape gardening.
Orange.—See [Citrus Fruit].
Osage Orange.—Used extensively for hedges, hence the name sometimes given to it, “hedge.” Fruit resembles an orange. Long thorns. Wood hard, but checks badly in drying; heart, a beautiful orange, sapwood yellow. Makes very durable fence posts.
Palm.—Palms come under the division Endogenous, or those that increase from within. Yuccas, cornstalks, sugar cane, bamboos are other examples of endogens. There are 1000 or more species of palms. Some of them are very decorative and in regions where they grow, such as Southern California and Florida, may be used very effectively for road and park embellishment. The Washington palm (Washingtonia filifera) grows to a height of 30 to 60 feet, with a tuft of fan-shaped leaves at the top. Old leaves die and hang down the tree like a thatched roof. Sometimes these are trimmed off, leaving a smooth stem nearly the same size all the way up. They are very effective in producing rows or avenues. Cabbage palmetto (Sabal palmetto) also has a long stem with a tuft of leaves at the top. The date palm (Phoenix dactylifera) has been grown quite successfully in Arizona. Several other species are available.
Pecan.—See [Hickory].
Pepper.—Snow[217] states that the California pepper tree or Peruvian mastic (Schinus molle) was introduced into California from Peru by the early Spanish missions. It is now a very popular street and road tree. In general appearance it suggests the drooping foliage of the weeping willow. It is very irregular and grows to 30 or 50 feet high with a spread nearly as great. The fine fern-like foliage and the long sprays of rose tinted berries make it very ornamental. It gives off a pleasant pungent peppery odor, and it is claimed to have the property of stopping dust, something greatly needed during the summer season in California.
Pignut.—One of the [Hickories], q. v.
Pine.—Nearly forty species of pine are found in the United States. They have high ornamental qualities and are used extensively in nearly every part of the country. Except on the great plains, one or more species are to be found. The different species grow from mere dwarfs to immense trees. For park purposes the white pine (Pinus strobus), an imported Scotch pine, an imported Norway pine, and the dwarf mugho have been very popular. (The sugar pine (P. lambertiana) grows in the high regions of California, is a fine tree and has cones 16 to 18 inches long).
Plane Tree.—See [Sycamore].
Plum.—Is used in thickets for screening and for its flowers and fruit. Pissard’s plum has been largely used for ornamental planting. The American plum (Prunus americana) works well in a general composition and is very thrifty.
Poplar.—The aspen, cottonwood, and balm of Gilead, have already been mentioned, one more needs attention, whitewood or tulip tree (Liriodendron tulipifera), found native in the eastern part of the United States. It is the tree from which the whitewood of commerce is mostly obtained. It grows to a height of 90 to 150 feet, and to a diameter of 6 to 12 feet, with a corresponding wide spread. It has been cut out until it is not particularly common any more. On account of the wood being soft, without knots, and free from season checks, the logs were utilized by the Indians for “dugout” boats. Hough states some were large enough to carry twenty or thirty persons. This, one of the most useful of American deciduous trees, deserves more liberal planting.
Quercus.—See [Oak].
Redwood.—These trees are native to California. There are two species—the mammoth trees (Sequoia washingtonia) of which a comparatively few large specimens remain, and the common redwood (S. sempervirens) which is now being rapidly cleared off by lumber companies. “Big or mammoth trees have been measured up to 320 feet in height and 35 feet in diameter” (Snow). These trees on account of the thick bark, on the large trees some 2 feet, resist fires very well. This is shown by ring counting and investigations on a fallen tree by Professor Dudley.[218] This tree dated back to 271 years before the Christian Era and showed that fires had occurred during the years A.D. 245, 1441, 1580, and 1797. The last fire charred a space 30 feet high and 18 feet broad, but full recovery had been made. The tree grows rapidly. Snow states that trees have been known to develop a height of 80 feet and a diameter of 16 inches in thirty years. In the Mariposa grove, at least partially under U.S. Forest Reserve, the roads wind about through the great natural avenues formed by these trees. On account of the great commercial value of redwood the trees might, in places where they will grow, be utilized for road planting to encourage their growth by others, and assist the government in its long-time forest plans.
Sassafras.—Native to the eastern part of the country is a good looking tree of small size, rising to a height of 30 to 50 feet with a spread one-third as great. It has the characteristic sassafras odor, the bark of the roots being used for medicine. Will mass well. The leaves being some lobed and some not lobed lend a pleasing variety. Is best in naturalistic planting.
Sequoia.—See [Redwood].
Shagbark.—See [Hickory].
Spruce.—Perhaps the most important evergreen used in landscape gardening, sharing that position with the pines. They seem to enjoy long winters and short summers, hence are well adapted to the Northern states. As they have a very trim symmetrical shape they can be utilized exceptionally well in formal planting. They go well also with informal planting, lending a splotch of green on an otherwise gray winter landscape. When planted at uniform spacing along an avenue they outline it exceedingly well without very much obstruction to clear vision if they are not set close together. The black (Picea nigra) and white (Picea alba) spruces rise from 40 to 100 feet in height with a compact symmetric conical shape. The black spruce has the darker foliage. The Colorado blue spruce (P. parryana) has been much in vogue as an ornamental tree, the new foliage having a blue tinge. Norway spruce (P. abies) has been used very largely in ornamental cultivation. The cones are large, 5 to 7 inches, nearly cylindrical, and the branches droop in artistic fashion. The Sitka Spruce (P. sichensis) of the Pacific coast region from Alaska to Northern California is a large tree of great commercial importance, and will grow well on low grounds.
Sugar Tree.—See [Maple].
Sycamore.—The plane tree or buttonwood (Platanus occidentalis) is found in the central and eastern portion of the United States, best in the Ohio and Mississippi River basins. It attains a height of 90 to 100 feet, and a spread of half as much. The outer bark peels off, leaving the inner exposed in white patches. Its straight, upright trunk and symmetrical form when allowed free growth ought to commend it for road planting. The fruit are rough balls about an inch in diameter which dangle in the air like ornaments on a Christmas tree. The California sycamore (P. racemosa) is a smaller tree with a poorer quality of wood, but in general appearance somewhat the same.
Tamarack.—See [Larch].
Teak.—A tree of great commercial importance in India and Africa. Has been transplanted to some extent in the Southern states but not yet sufficiently numerous to be considered a road tree.
Thorn.—Several members of the Cratægus family are suitable for landscape planting. Crataegus crus-galli, C. tomentosa, and C. coccinea, native plants, and the English hawthorn, C. oxyacantha, are all recommended where small trees are desired.
Tulip Tree.—See [Poplar].
Tupelo.—Same as Black or Sour [Gum].
Ulmus.—See [Elm].
Walnut.—Three species of walnut are used for road trees—black walnut, butternut, and English (Persian) walnut. The black walnut (Juglans nigra) makes a handsome tree when allowed to develop individually, from 90 to 125 feet high, and 3 to 8 feet in diameter with a normal spread about one-half the height of the tree. The edible nuts are the delight of the small boy and as they are usually gathered up from the ground after they fall their collection will not injure the tree. The foliage is not very dense and it will not take away greatly the fertility of neighboring ground hence, makes an almost ideal road tree. Since the World War, according to Reed[219] it has been considered a favorite as a memorial tree. Its native habitat is the eastern half of the United States intermittently from the Atlantic to Nebraska and Texas, but it thrives when transplanted to the states of Oregon and Washington and is being used extensively by the State of California as a road tree. The trees grow well from the nut or they may be transplanted from a nursery by cutting the tap root one year ahead of transplanting as is necessary for most nut trees. The butternut (J. cinerea), sometimes called white walnut, is a very similar tree, a little smaller and has not quite so extensive a native range. The nuts are not round like the black walnut, but lanceolate in shape. On the whole the black walnut is the better road tree. The English walnut (J. regia) is a native of Persia, but is grown very largely in orchards in California where the annual crop of nuts is more than 20,000,000 pounds. Hardy varieties suitable for more severe climates are advertised but it is not here recommended that they be planted where experience has not shown them to thrive. The tree itself is of fine appearance, and in the warmer climates makes a good road tree.
White Wood.—A name given to trees of various genera. See [Basswood], [Poplar].
Willow.—Willows may be used in decorative planting to a considerable extent, especially along banks to keep them from washing and other low places. The black willow (Salix nigra) grows into an interesting tree with a rough trunk and long pendulous limbs and narrow lance-shaped leaves. It resembles in general appearance the pepper trees of California. It should be used more as a road tree across low bottoms. It grows only 40 to 50 feet high, but its spread is fully as much, giving it a rounded, ball-shaped top. Salix regatis, S. alba, S. vitillina aurea, and S. laurifolia are all recommended for decorative effects.
Yucca.—Many of the yuccas are merely herbaceous plants with beautiful flowers, but the Joshua tree (Yucca arborescens) grows to be 25 to 40 feet in height, and two feet in diameter; it is so very ungainly that it is picturesque.