TULIP TREE.

[81]Platanus occidentalisL.

The California sycamore[82]is a native of California adapted to regions 1, 2, 3, and 4 and portions of region 5. It is similar in general characteristics to the sycamore.

[82]Platanus racemosaNutt.

The London plane tree[83]is one of the Old World forms of sycamore. According to Alfred Render,[84]"the true oriental plane is rare in cultivation, the tree usually planted under this name beingPlatanus acerifolia" It it more compact in habit of growth and has the other good qualities of the sycamore. It is being more and more used on city streets and is proving satisfactory in regions 1, 2, 3, 4, 9, 10, 11, and 12. It will probably succeed in the warmer parts of regions 6 and 7 and also in regions 5 and 8. It is a more desirable tree for ordinary use than the sycamore, on account of its more compact habit and comparative freedom from disease, though it is tender in the northernmost sections.

[83]Platanus acerifolia(Ait.) Willd.

[84]Bailey, L. H., ed. New York, 1916. Standard Cyclopedia of Horticulture, v. 5, p. 2707.

The tulip tree[85]is also sometimes called the tulip poplar or yellow poplar, though the latter names are unfortunate, as the tree is not a poplar or even closely related to the poplars. It is a large, rapid-growing tree suitable for suburban conditions in regions 1, 2, 10, 11,and 12. The leaves are of unusual form, the upper half appearing to have been cut away, leaving a notch about where it would seem the middle of the leaf should be. The color is a light green. The roots are unusually soft and tender, and therefore the tree needs to be transplanted quickly and with great care. Small sizes should be planted, especially near the northern limits of growth. It should be transplanted only in the spring. If after transplanting it the top should die and a new vigorous shoot should put out from the root, it would be desirable to form a new top from this shoot rather than to transplant another tree.

[85]Liriodendron tulipiferaL.

Nursery-grown trees should be used for street planting, and they should have been transplanted at least every two years while in the nursery. This is to insure a thorough root pruning and the production of numerous fibrous roots close to the trunk. Trees not frequently transplanted form a few long roots that are largely cut off when the tree is dug. Trees growing in the woods form a few very long roots, and when an attempt is made to dig them only a little of the root next the trunk is obtained, while most of the roots, including the fibrous ones, are left in the ground. If woodland trees are wanted for street purposes, most kinds should be grown for a few years in a nursery in order to form a good root system before being planted on the streets.

In addition to a good root system, the tree should have a straight trunk for the variety, with a good set of branches, called the head, the bottom branches being from 7 to 9 feet from the ground. Trees which naturally head low should be started with a higher head than those varieties that have a tendency to an upright growth. A good head for a shade tree is a leader or upright branch with three or more side branches about equally spaced around the tree. The trees should be healthy, free from scars, and also free from evidences of insects or diseases. In the presence of insects, trees should be thoroughly fumigated along approved methods before leaving nurseries, to insure against the introduction and distribution of pests. Weakened vitality resulting from transplanting and subsequent neglect will frequently invite attack by bark-boring insects which seriously damage or kill the trees. Mulching and watering will often prevent this damage.

Opinion as to the size to plant differs somewhat, but for average conditions trees from 10 to 12 feet high and with trunks or stems from 2 to 21/2inches in diameter[86]are very satisfactory in mostvarieties used for street purposes. With such varieties as elms sycamores, and some southern oaks, somewhat larger trees can be used equally well, while smaller trees would be better in the regions of limited rainfall both east and west of the Rocky Mountains and for tulip trees and sweet gums, especially in the northern portion of their range of usefulness.

[86]Designated by nurserymen as "caliper."

Next to the selection of a proper variety, the preparation of the hole is the most important detail of street tree planting. Because of the restricted area available for the spread of the tree roots, and owing to the artificial conditions imposed by the improvement of city streets, the soil provided for the feeding ground of the roots of the young tree must be liberal in quantity and of the best quality. From 2 to 3 cubic yards of soil should be provided for each tree. It is desirable to have at least 18 square feet of opening in the sidewalk, especially if it is of concrete or other impervious material. Trees will grow with smaller sidewalk openings, but they are not likely to thrive so well, and it is impossible properly to prepare a hole for planting a tree without disturbing at least this much surface soil. The proper depth of soil is from 21/2to 3 feet. A hole 3 feet deep large enough to hold 2 cubic yards of soil has a surface area of 18 square feet. A hole 6 feet long, 3 feet wide, and 3 feet deep will hold 2 cubic yards of soil, will have the smallest desirable surface area, and will be of such dimensions as will best conform to the usual sidewalk and roadway widths and thus not interfere with traffic.

The tree hole must be so drained that water will not stand in it. If the soil is so impervious as to hold water some artificial drainage must be provided. That portion of the depth of a hole that acts as a cistern for holding water is valueless as a feeding ground for roots. For every cubic foot of soil in the bottom of a hole that might thus be made valueless by standing water, 11/2cubic feet of soil should be added by increasing the length or width of it. Under no circumstances, however, should the depth of available feeding ground be less than 2 feet. The deeper the roots may be encouraged to grow, the less injury is likely to be experienced from drought.

The soil used should be topsoil from land that has been producing good crops. This should be well enriched with rotted manure, one part of manure to four of soil. The addition of such fertilizers as ground bone, tankage, fish scrap, or cottonseed meal at the rate of 1 pound to the cubic yard of soil is also helpful. Commercial fertilizers containing mostly phosphoric acid obtained from other substances than ground bone are not to be recommended for use in the soil about the roots at planting time. When used they should form a surface application, worked into the soil after planting.

P20370HPFig. 29.—Trees properly "heeled in."

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Fig. 29.—Trees properly "heeled in."

If trees are shipped from a distance they should be taken at once on arrival to some point where the roots may be carefully covered with soil; there they should be unpacked and plenty of loose moist earth worked thoroughly around and over the roots as fast as they are taken from the box. This temporary covering of the roots is called "heeling in." (fig. 29) The tops may be either erect or laid almost on the ground in successive rows, the tops of one row lying over the roots of the previous rows, the object being to cover the roots thoroughly and keep them moist until the tree is wanted for permanent setting. Not a moment of exposure should be permitted between the box and the soil. If the roots appear dry, they may be dipped for a few minutes before "heeling in" in a tub of water or in thin mud.

P20000HPFig. 30.—Trees handled in a careless manner. The roots should have been covered with wet canvas.

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Fig. 30.—Trees handled in a careless manner. The roots should have been covered with wet canvas.

Trees in large quantities are often packed directly in cars with a small quantity of straw about the roots. When shipped in this way extra care (compare figs.30and31) must be exercised in taking the trees to the point where they are to be heeled in. The wagon in which they are to be hauled should have a tight box, and wet canvas should be tied tightly over the load. The last is important, so that there may be no chance for the roots to dry.

When taking trees from the ground where they have been heeled in to the place for planting, great care must also be exercised to see that the roots are not exposed to sun or wind, but are kept closely covered with moss, wet burlap, or canvas until planted. Lack of care in this matter is a greater cause of loss in tree planting than carelessness in any other particular. One city that has its own nursery and uses largely trees that are supposed to be difficult to move, but is careful about not exposing the roots for a moment (fig. 31), has a loss of less than 1 per cent. If the roots once dry the trees will die, and it takes but a short exposure to dry the roots. The holes should be prepared well in advance of planting, so that no time will be lost when conditions are right for putting the trees in the ground.

P20350HPFig. 31.—A load of trees and tree boxes. The roots are packed in wet moss and a tree is not taken from the wagon until the planter and two shovelers are at the hole where it is to be planted.

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Fig. 31.—A load of trees and tree boxes. The roots are packed in wet moss and a tree is not taken from the wagon until the planter and two shovelers are at the hole where it is to be planted.

In regions 1, 10, 11, 12, and 13 (fig. 17) the best time for planting deciduous street trees is the month or six weeks just preceding freezing weather in the fall. The other desirable time for planting is as soon after freezing weather is over in the spring as the ground is dry enough for the mechanical operations. This should be as early as possible, as the more opportunity there is for root growth before warm weather forces the top into growth, the better the results are likely to be. In regions 6, 8, and 9, where the ground freezes to a considerable depth, spring planting is to be preferred to fall planting unless it is possible to drench the soil thoroughly for a considerable distance around the trees at planting time and after that to mulchthe soil thoroughly and also to protect the top from the effect of drying winter winds. Where mice abound they may be harbored in the mulch and may girdle the tree. This may be prevented by a collar of wire netting about the base of the trunk or by banking the earth about it. The death of trees at the time of transplanting is due to the drying out of either roots or tops before opportunity is given them to become reestablished in their new locations. This drying may be due to improper exposure at the time of digging or before packing (fig. 30), poor packing, prolonged delay in delivery, improper handling between unpacking and planting, or the existence of conditions conducive to excessive drying out of the plant after setting.

P14340HPFig. 32.—A city nursery.

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Fig. 32.—A city nursery.

The atmosphere is continually claiming a tribute of moisture from all living plants, whether the plant is in leaf and growing or is dormant. Growing plants, and dormant plants under normal conditions, are able to replace this moisture by absorption through the roots. In climates where newly planted trees may obtain sufficient soil water to replace these losses by drying, fall planting is best. Where the plants are unable to get sufficient winter moisture, planting would better be done only in the spring. Where the soil freezes to a depth greater than that to which the plant roots extend, the supply of water is cut off from the roots and the tree will be killed by drying out through evaporation from the top. Where winter winds are very drying and the soil moisture is limited, evaporation from the top is likely to be in excess of that supplied by the roots and the tree is killed in the same way.

Fig. 33.—Setting a tree:A, Measuring from the curb to get the tree in line;B, filling the hole:C, placing the box;D, fastening the box.

In regions normally adapted to fall planting, newly set trees may be killed by a dry autumn followed by a dry winter with, high winds or by a cold winter with so little snow that the ground freezes below the roots. On the other hand, trees may often be successfully planted in the fall where such practice is not usually successful by thoroughly mulching the soil if freezing is the sole cause of the difficulty, or bydrenching the soil thoroughly and then mulching well if lack of moisture and high winds are the causes of the trouble. Protection from the wind by wrapping the trunk and large limbs with burlap or some other protecting material is also desirable.

After a liberal opening has been made in the specially prepared soil the tree should be brought, preferably from the city's own nursery (fig. 32), but if such a nursery has not been provided, then from among the newly received trees that have been "heeled in" as already described.

If the tree has been well handled and the roots carefully protected it is ready for setting. It is desirable to immerse the roots in a thin mixture of clay and water just before putting it in the hole if there is suspicion that the roots have been exposed. This can be done before leaving the nursery or "heeling in" ground, but the roots must be properly protected. Any mutilated ends of roots should be removed, the top should be severely pruned, as described later, and the tree should be placed in the hole in line with the other trees (fig. 33,A) and at such a height that after the filling is completed it will be about an inch deeper in the ground than it was before transplanting. The roots should be spread out in as near their original position as practicable, and soil should be carefully worked in about them with the fingers, so that each rootlet may come in contact with soil and not be crowded against other rootlets. When all the roots have been placed and covered the soil should be thoroughly trampled or tamped to bring the roots into as close contact as possible with it. Then more soil should be put in and the ground again tamped. Of course, in order to get satisfactory results the soil used for planting must not be too wet or too dry. If the soil is in such a state as to hold together in soggy masses and not spring apart again when squeezed in the hand, it is too wet for planting. If the soil is too dry, it will not stay in contact with the roots during the planting operations. A soil that is too dry may be well-watered a day or two in advance of the planting, or if excessive dryness does not make it difficult to handle, the tree may be planted and then be thoroughly watered. After the watering 3 or 4 inches of loose soil should be spread over the wet ground in order to prevent undue evaporation. It should not be trampled or pounded in any way after the water is applied. If trees planted in moist retentive soils are watered after planting they should be provided with a mulch of similar earth. East of the Missouri River trees planted in soil that is in good condition usually do not need watering at the time of planting.

Trees planted from pots, cans, or boxes should have the ball of earth taken from the receptacle handled with care, so as not to break it further than to loosen some of the roots on the outside of the ball; then the soil should be as carefully placed about this balland the loosened roots as about the roots of trees without balls. Trees planted with balls need no root pruning and little top pruning.

P20367HPFig. 34.—A pin oak trimmed for planting. Note the bad stubs (A, A) on the left-hand side of the tree.

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Fig. 34.—A pin oak trimmed for planting. Note the bad stubs (A, A) on the left-hand side of the tree.

P20368HPFig. 35.—A sycamore trimmed for planting. Well primed, without bad stubs.

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Fig. 35.—A sycamore trimmed for planting. Well primed, without bad stubs.

At planting time the trees should be so pruned as to remove from one-half to three-fourths of the leaf buds. The head should be formed in the nursery, so that at planting time the only problem is how to reduce the amount of prospective growth the first season without destroying the form of the head. Specific directions are difficult, because different species of trees are so different in their character of growth. A species that is naturally compact in growth (fig. 34) should be pruned by removing whole branches rather than by having the ends of branches removed. One that is open and spreading (fig. 35) will probably need the shortening of the longer limbs as well as the removal of interior branches. The first pruningshould be the removal of such branches as can be spared. If enough buds can not be removed in this way without leaving the head too open, then the shortening of the branches must follow. It is usually necessary to remove three-fourths of the limbs to accomplish this. An expert can do this pruning or most of it more easily before the tree is planted than afterwards. Some additional pruning may be necessary after the tree is set.

In addition to the pruning of the top the roots may need some cutting. Any broken pieces or ends should be removed, making a clean cut with a sharp knife, as new rootlets put out more readily from a cleanly cut fresh surface than from ragged breaks. If the roots are very long, without branches or rootlets, it sometimes makes planting easier to cut off some of the ends. As roots are the braces by which a tree is supported in the ground, it is undesirable to reduce their length unless some positive good is to be gained by it.

P20372HPFig. 36.—Types of tree guards.

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Fig. 36.—Types of tree guards.

The best implement for cutting small limbs is a sharp knife, and for larger limbs a fine-toothed saw. Pruning shears are sometimes used, but they are likely to bruise the wood. If used at all, the blade should always be turned toward the tree so that the bruise made by the supporting bar will be on the portion cut off. Where branches are taken off, the cut should be close to the remaining limb, so that no suggestion of a stub will remain. (Figs.34and35.) Where ends are cut from branches the cut should be just above a bud, and the remaining bud should point in the direction that it is desired the limb should grow.

Under city conditions young trees need the support of a strong stake as well as protection for the trunk. Boys like to swing around small trees or see the tops fly up if bent to the ground. Men find them convenient hitching posts for their horses, and horses frequentlylike the taste of the bark or tear it off for the sake of having something to do.

Guards are of many forms (fig. 36), from stakes 21/2inches square set 3 feet in the ground and extending 6 feet above, with heavy-netting placed about the tree and stapled to the stake, to heavy wooden cribs of four stakes and intermediate slats and wrought-iron patterns of many forms.

The trees should be firmly secured to the tops of the guards so that they will not swing against them in the wind and be rubbed. This is best done by securing the tree in place in the guard by two loops of pieces of old garden hose, soft leather, or rope, in such a way as not to bind the tree too tightly while keeping it from swinging much or rubbing. The essentials are a firm support for the tree while young with reasonable protection of the trunk from careless depredations until the tree has reached a diameter of 6 inches or more.

If after planting, the season is dry and it becomes necessary to apply water, the ground should be soaked thoroughly, and as soon as it has dried sufficiently to work up loosely it should be hoed or raked to make a good earth mulch. A mulch of strawy manure or litter may be used in place of the earth mulch if desired. The watering should not require repeating for a week or more.

If the weather becomes warm soon after planting and the trees come into leaf, wither, and droop, further pruning may save them. The reason for the difficulty is probably that the growth of the top has been greater than the newly formed roots can support; therefore the additional pruning is likely to restore the balance between the top growth and root growth. At least three-fourths of the remaining young wood should be removed. This may leave the tree looking almost like a bean pole, but if it induces a vigorous root growth the top can easily be re-formed.

Young trees should have an annual inspection, and all crossing branches and any that are not well placed to form a good head should be removed. Attention should be given also to all forks, and where two branches start almost parallel to one another or at a small angle, making a fork liable to split apart as the tree grows, one branch should be removed. Where three branches start from almost the same point there is little likelihood of their splitting apart, but with only two growing at a less angle than 30° there is liable to be trouble in the case of most kinds of trees. On trees on which few but long shoots form, it may be well to remove the ends of such shoots. As a rule, it is undesirable to use for street planting trees with this kind of growth. Young trees should be trained into a desirable shape by the use of a pruning knife each year, so that a saw will not be necessary later. Some trees have a tendency toform too dense a head. The interior branches of these should be removed and the head made as open as possible while the work can be done with a knife. No attempt should be made to alter the natural form of a tree but only to insure its best development. A skillfully pruned young tree will show no evidences of the pruning after three or four years.

It is very little trouble to train a tree into a good shape by using the pruning knife while the limbs are small, but it is usually difficult to re-form a tree after it has grown to maturity. One who understands tree growth, however, can often reshape the top of a neglected tree to advantage, though many who make a business of tree trimming know so little about it that they do more harm than good. More mature trees have been hurt by severe pruning than have been helped. Of course, dead or dying wood should be removed whenever it is found, no matter what the age of the tree. This should be done by cutting off the limb back to the nearest healthy crotch. A limb should not be cut off square across (fig. 21) unless the tree is apparently in a dying condition and the whole top is treated thus in an attempt to save its life. In such a case, a second pruning should follow within two years, at which time the stubs left at the first trimming should be cut off in a proper manner near the newly started limbs. Healthy silver maples and willows are frequently cut in this way, but the maples in particular would better be cut down at once than to subject the public to the dangers of the insidious decay that almost always follows such an operation on these trees and completes their destruction promptly.

Trees that have been neglected a long time frequently have interfering or crossing branches, or are too low headed or too densely headed for the place where they are growing. Defects of this kind may be at least partially remedied. The removal of limbs by cutting them off at a crotch in such a manner that the wound is parallel with the remaining branch (fig. 37) inflicts the least possible damage. Such a wound in a healthy tree will soon heal over if the cut is made through the slight collar or ring that is nearly always present at the base of a branch. The closer this cut can be made to the trunk the better the appearance when the cut is healed. The closer the cut the larger the wound, but the difference is unimportant if the wood is well protected until it is healed. These operations are entirely different in purpose and result from the "heading in" or "heading back" so often practiced under the guise of tree pruning, either from a false notion of forming a top or for the passage of wires.

Changing the form of a tree by pruning should not be attempted. Each species has its own form or forms, and no attempt should bemade to change or distort a tree from its normal habit of growth. Successful pruning will accentuate rather than disguise a tree's characteristics.

P20371HPFig. 37.—Part of a tree trunk showing proper and improper methods of removing old limbs. Although healing has started on the stub (at the right) it is likely to proceed very slowly. The nearer the cut is to the tree the larger the wound but the less conspicuous the stub will be when healed.

P20371HP

Fig. 37.—Part of a tree trunk showing proper and improper methods of removing old limbs. Although healing has started on the stub (at the right) it is likely to proceed very slowly. The nearer the cut is to the tree the larger the wound but the less conspicuous the stub will be when healed.

All cuts should be made so that no stubs or protuberances are left to prevent quick healing. Small wounds need no after treatment if the cut is well made. Large wounds should have the wood of the center of the cut well protected to prevent decay until the new growth has had an opportunity to heal over the cut. An application made to the center of the cut to preserve the wood should not be permitted to come near the cambium layer or inner bark, especially of soft-wooded trees like the tulip and magnolia, as the oil or other substances contained in the paint, tar, or other covering may spread to the cambium layer and kill it. It is well not to make any application within half an inch of the outside of the wound unless the coating has been thoroughly tested.

Dead wood should be entirely removed, the cut being made through good live tissue. Removing such wood frequently exposes decayed cavities, usually from bad stubs or injuries which have started decay that has followed back to the main limbs or the trunk. The treatment of such cavities is the province of tree surgery and is discussed in another publication.[87]

[87]Collins, J. F. Practical tree surgery.InU. S. Dept. Agr. Yearbook, 1913, pp. 163-190, pl. 16-22. Published as Yearbook Separate 622, obtainable from the Superintendent of Documents for 10 cents in coin.

One source of trouble with a large tree that has developed with two trunks or branches instead of three or more is the liability of their splitting apart in the crotch. This is especially characteristic of the elm. Careful attention to the early pruning of trees may eliminatethis defect, but when it exists in mature trees it is frequently advisable to connect the branches by a strong chain (fig. 18) in order to prevent the limbs from being torn apart.

It is difficult to do anything to stimulate the growth of street trees after they are once started, because usually the only uncovered area over the roots is the small opening immediately about the tree; hence, the importance of supplying the best of soil well enriched at the time of planting. Sometimes a stimulation is desirable, which can be accomplished by dissolving one-half to 1 pound of nitrate of soda in 50 gallons of water and applying from 1 to 25 gallons of the liquid, depending on the size of the tree. Unless the soil is damp at the time of application water will be needed immediately afterward. This material should be applied only when the tree is in full leaf and growing. If applied when the tree is dormant it is likely to be leached from the soil before it is absorbed. If applied late in the season, that is, within three months of freezing weather, it would likely stimulate a late growth that would be liable to be killed the following winter and might make the whole tree more susceptible to injury from cold.

Water is one of the great needs of city trees, as the ground surface is often almost completely roofed over with water-tight coverings. It is usually a help for the pavement washings to drain into the parking space where the tree is planted. If a curb is placed about the parking space, frequent, regular watering is necessary where the ground is thoroughly covered with water-tight pavements.

Where growing under suburban conditions, that is, with streets partially pervious to water, liberal parking spaces, and adjoining lawns, street trees will respond to all extra care given the near-by open spaces, whether parkings, lawns, or gardens. If these are well cared for the trees should have ample sustenance from them without any direct applications.

In order to prevent the soil about a tree from being packed too hard by trampling it is frequently desirable on business streets to cover the soil about it with an iron grating.

Street trees, like all other forms of vegetation, are subject to attacks of insects and diseases. Because of the unfavorable conditions under which they grow, spraying for biting and sucking insects and suitable treatment for borers or other burrowing insects require especially careful attention.

In addition to a number of troubles common to street trees in general, each species is liable to troubles of its own; hence, the need of competent supervision by a trained man with an efficient outfit rather than leaving; the work to individual initiative.

Because of the height which many street trees attain a powerful outfit is required to spray them properly. One capable of maintaining a pressure of 200 pounds per square inch is desirable. The type of spray required for tall trees is different from that used on fruit trees and other low plants. For low trees the ideal spray is a mist within a few feet of the nozzle, application being accomplished by having the nozzles near the foliage to be treated. For tall trees it is desirable that the liquid should leave the nozzle in a solid stream, which is broken into spray as it passes through the air. The material has to be projected with sufficient force to reach the highest trees before being entirely converted into mist, as it is impracticable to extend the nozzles into the trees to reach the farthest portions, as is done with fruit and other low trees. The spray can not be applied as uniformly as a mist, but it is impracticable to climb into the tops of shade trees to cover every part with a cloudlike spray. On the other hand, the mist spray is better for small trees, as much injury may be done to low trees or to the lower branches of high trees by the force of the stream from high-pressure outfits.

It is estimated that in practice up to 95 per cent of the attacking insects can be killed with insecticides carefully applied by the stream method under high pressure.

In addition to the mechanical problem of satisfactorily covering high trees with insecticides or fungicides there is the problem of selecting materials that will be effective against the insects and diseases and at the same time will not disfigure the paint or stone work of adjacent buildings with which the materials must inevitably come in contact in street tree spraying. It frequently happens that the most effective remedies must be rejected because of the damage they would do to buildings and that less efficient materials must be used.

Whitewashing the trunks of trees is a useless and unsightly practice—useless, as it does not prevent the attacks of insects, and unsightly, because it makes the trunks of the trees obtrusive when they should be inconspicuous.

Banding with cotton or proprietary preparations may occasionally be useful, but because such applications are so seldom helpful and because some of the preparations result in injury due to constriction of the trunks, it should not be resorted to except upon special recommendation of an entomologist familiar with the existing conditions.

Details as to enemies to be expected, methods of treatment, and materials to be used may be found in other publications[88]or may be obtained by correspondence with the nearest State agricultural experiment station or with the United States Department of Agriculture.

[88]See list on following pages.

PUBLICATIONS OF THE UNITED STATES DEPARTMENT OF AGRICULTURE RELATING TO DISEASES AND INSECTS AFFECTING SHADE AND ORNAMENTAL TREES.

AVAILABLE FOR FREE DISTRIBUTION.

Control of Root-Knot. (Farmers' Bulletin 648.)The San Jose Scale and Its Control. (Farmers' Bulletin 650.)The Bagworm, an Injurious Shade-Tree Insect. (Farmers' Bulletin 701.)The Catalpa Sphinx. (Farmers' Bulletin 705.)The Leopard Moth: A Dangerous Imported Enemy of Shade Trees. (Farmers' Bulletin 708.)The Oyster-Shell Scale and the Scurfy Scale. (Farmers' Bulletin 723.)The White-Pine Blister Rust. (Farmers' Bulletin 742.)Carbon Disulphid as an Insecticide. (Farmers' Bulletin 799.)The Gipsy Moth and the Brown-Tail Moth and Their Control. (Farmers' Bulletin 845.)Common White Grubs. (Farmers' Bulletin 940.)The Blights of Coniferous Nursery Stock. (Department Bulletin 44.)Forest Disease Surveys. (Department Bulletin 658.)

Control of Root-Knot. (Farmers' Bulletin 648.)

The San Jose Scale and Its Control. (Farmers' Bulletin 650.)

The Bagworm, an Injurious Shade-Tree Insect. (Farmers' Bulletin 701.)

The Catalpa Sphinx. (Farmers' Bulletin 705.)

The Leopard Moth: A Dangerous Imported Enemy of Shade Trees. (Farmers' Bulletin 708.)

The Oyster-Shell Scale and the Scurfy Scale. (Farmers' Bulletin 723.)

The White-Pine Blister Rust. (Farmers' Bulletin 742.)

Carbon Disulphid as an Insecticide. (Farmers' Bulletin 799.)

The Gipsy Moth and the Brown-Tail Moth and Their Control. (Farmers' Bulletin 845.)

Common White Grubs. (Farmers' Bulletin 940.)

The Blights of Coniferous Nursery Stock. (Department Bulletin 44.)

Forest Disease Surveys. (Department Bulletin 658.)

FOR SALE BY THE SUPERINTENDENT OF DOCUMENTS,GOVERNMENT PRINTING OFFICE, WASHINGTON, D. C.

The Mistletoe Pest in the Southwest. (Bureau of Plant Industry Bulletin 166.) Price, 10 cents.The Death of Chestnuts and Oaks Due to Armillaria mellea. (Department Bulletin 89.) Price, 5 cents.New Facts Concerning the White-Pine Blister Rust. (Department Bulletin 116.) Price, 5 cents.The Huisache Girdler. (Department Bulletin 184.) Price, 5 cents.Report on the Gipsy Moth Work in New England. (Department Bulletin 204.) Price, 30 cents.A Disease of Pines Caused by Cronartium pyriforme. (Department Bulletin 247.) Price, 5 cents.Food Plants of the Gipsy Moth in America. (Department Bulletin 250.) Price, 10 cents.Dispersion of Gipsy Moth Larvæ by the Wind. (Department Bulletin 273.) Price, 15 cents.The Cottonwood Borer. (Department Bulletin 424.) Price, 5 cents.Solid-Stream Spraying against the Gipsy Moth and the Brown-Tail Moth in New England. (Department Bulletin 4.80.) Price, 15 cents.Protection from the Locust Borer. (Department Bulletin 787.) Price, 5 cents.Principal Insects Liable to be Distributed on Nursery Stock. (Entomology Bulletin 34, n. s.) Price, 5 cents.The Locust Borer. (Entomology Bulletin 58, part 1.) Price, 5 cents.Additional Data on the Locust Borer. (Entomology Bulletin 58, part 3.) Price, 5 cents.The San Jose or Chinese Scale. (Entomology Bulletin 62.) Price, 25 cents.Report on Field Work against the Gipsy Moth and the Brown-Tail Moth. (Entomology Bulletin 87.) Price, 35 cents.The Importation into the United States of the Parasites of the Gipsy Moth and the Brown-Tail Moth. (Entomology Bulletin 91.) Price, 65 cents.The Dispersion of the Gipsy Moth. (Entomology Bulletin 119.) Price, 20 cents.The Green-Striped Maple Worm. (Entomology Circular 110.) Price, 5 cents.The Oak Pruner. (Entomology Circular 130.) Price, 5 cents.The Dying Hickory Trees: Cause and Remedy. (Entomology Circular 144.) Price, 5 cents.Flour Paste as a Control for Red Spiders and as a Spreader for Contact Insecticides. (Entomology Circular 166.) Price, 5 cents.Three Undescribed Heart-Rots of Hardwood Trees, Especially of Oak. (Journal of Agricultural Research, vol. 1, No. 2.) Price, 25 cents.A Serious Disease in Forest Nurseries Caused by Peridermium filamentosum. (Journal of Agricultural Research, vol. v, No. 17.) Price, 10 cents.The Chestnut Bark Disease. (Separate 598, from Yearbook of the Department of Agriculture for 1918.) Price, 10 cents.Practical Tree Surgery. (Separate 622, from Yearbook of the Department of Agriculture for 1913.) Price, 10 cents.Forest Tree Diseases Common in California and Nevada. (Forest Service Unnumbered Publication.) Price, 25 cents.

The Mistletoe Pest in the Southwest. (Bureau of Plant Industry Bulletin 166.) Price, 10 cents.

The Death of Chestnuts and Oaks Due to Armillaria mellea. (Department Bulletin 89.) Price, 5 cents.

New Facts Concerning the White-Pine Blister Rust. (Department Bulletin 116.) Price, 5 cents.

The Huisache Girdler. (Department Bulletin 184.) Price, 5 cents.

Report on the Gipsy Moth Work in New England. (Department Bulletin 204.) Price, 30 cents.

A Disease of Pines Caused by Cronartium pyriforme. (Department Bulletin 247.) Price, 5 cents.

Food Plants of the Gipsy Moth in America. (Department Bulletin 250.) Price, 10 cents.

Dispersion of Gipsy Moth Larvæ by the Wind. (Department Bulletin 273.) Price, 15 cents.

The Cottonwood Borer. (Department Bulletin 424.) Price, 5 cents.

Solid-Stream Spraying against the Gipsy Moth and the Brown-Tail Moth in New England. (Department Bulletin 4.80.) Price, 15 cents.

Protection from the Locust Borer. (Department Bulletin 787.) Price, 5 cents.

Principal Insects Liable to be Distributed on Nursery Stock. (Entomology Bulletin 34, n. s.) Price, 5 cents.

The Locust Borer. (Entomology Bulletin 58, part 1.) Price, 5 cents.

Additional Data on the Locust Borer. (Entomology Bulletin 58, part 3.) Price, 5 cents.

The San Jose or Chinese Scale. (Entomology Bulletin 62.) Price, 25 cents.

Report on Field Work against the Gipsy Moth and the Brown-Tail Moth. (Entomology Bulletin 87.) Price, 35 cents.

The Importation into the United States of the Parasites of the Gipsy Moth and the Brown-Tail Moth. (Entomology Bulletin 91.) Price, 65 cents.

The Dispersion of the Gipsy Moth. (Entomology Bulletin 119.) Price, 20 cents.

The Green-Striped Maple Worm. (Entomology Circular 110.) Price, 5 cents.

The Oak Pruner. (Entomology Circular 130.) Price, 5 cents.

The Dying Hickory Trees: Cause and Remedy. (Entomology Circular 144.) Price, 5 cents.

Flour Paste as a Control for Red Spiders and as a Spreader for Contact Insecticides. (Entomology Circular 166.) Price, 5 cents.

Three Undescribed Heart-Rots of Hardwood Trees, Especially of Oak. (Journal of Agricultural Research, vol. 1, No. 2.) Price, 25 cents.

A Serious Disease in Forest Nurseries Caused by Peridermium filamentosum. (Journal of Agricultural Research, vol. v, No. 17.) Price, 10 cents.

The Chestnut Bark Disease. (Separate 598, from Yearbook of the Department of Agriculture for 1918.) Price, 10 cents.

Practical Tree Surgery. (Separate 622, from Yearbook of the Department of Agriculture for 1913.) Price, 10 cents.

Forest Tree Diseases Common in California and Nevada. (Forest Service Unnumbered Publication.) Price, 25 cents.

ADDITIONAL COPIESOF THIS PUBLICATION MAY BE PROCURED FROMTHE SUPERINTENDENT OF DOCUMENTSGOVERNMENT PRINTING OFFICEWASHINGTON, D. C.AT15 CENTS PER COPY

Transcriber NotesIllustrations were moved so as to not split paragraphs.

Transcriber Notes

Illustrations were moved so as to not split paragraphs.

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