The Project Gutenberg eBook ofStreet Trees

The Project Gutenberg eBook ofStreet TreesThis ebook is for the use of anyone anywhere in the United States and most other parts of the world at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this ebook or online atwww.gutenberg.org. If you are not located in the United States, you will have to check the laws of the country where you are located before using this eBook.Title: Street TreesAuthor: Furman Lloyd MulfordRelease date: July 16, 2020 [eBook #62677]Most recently updated: October 18, 2024Language: EnglishCredits: Produced by Tom Cosmas*** START OF THE PROJECT GUTENBERG EBOOK STREET TREES ***

This ebook is for the use of anyone anywhere in the United States and most other parts of the world at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this ebook or online atwww.gutenberg.org. If you are not located in the United States, you will have to check the laws of the country where you are located before using this eBook.

Title: Street TreesAuthor: Furman Lloyd MulfordRelease date: July 16, 2020 [eBook #62677]Most recently updated: October 18, 2024Language: EnglishCredits: Produced by Tom Cosmas

Title: Street Trees

Author: Furman Lloyd Mulford

Release date: July 16, 2020 [eBook #62677]Most recently updated: October 18, 2024

Language: English

Credits: Produced by Tom Cosmas

*** START OF THE PROJECT GUTENBERG EBOOK STREET TREES ***

UNITED STATES DEPARTMENT OF AGRICULTUREBULLETIN No. 816Contribution from the Bureau of Plant IndustryWm. A. Taylor, ChiefWashington, D. C.â–¼January 19, 1920STREET TREESByF. L. MULFORD, HorticulturistOffice of Horticultural andPomological InvestigationsCONTENTSPageImportance of Shade Trees1Public Control of Street Trees6Planning for Trees on City Streets8Spacing Trees9Conditions for Tree Growth10Kinds of Trees Suitable for City Streets14Qualities Necessary14Trees for Different Regions20Descriptions of Street Trees20Culture of Street Trees43Selection of Individual Trees43Preparation of Holes44Planting45Pruning50Stakes and Guards51Later Care52Care of Mature Trees53Pruning53Feeding55Spraying55WASHINGTONGOVERNMENT PRINTING OFFICE1920

UNITED STATES DEPARTMENT OF AGRICULTURE

BULLETIN No. 816

Contribution from the Bureau of Plant Industry

Wm. A. Taylor, Chief

Office of Horticultural andPomological Investigations

CONTENTS

PageImportance of Shade Trees1Public Control of Street Trees6Planning for Trees on City Streets8Spacing Trees9Conditions for Tree Growth10Kinds of Trees Suitable for City Streets14Qualities Necessary14Trees for Different Regions20Descriptions of Street Trees20Culture of Street Trees43Selection of Individual Trees43Preparation of Holes44Planting45Pruning50Stakes and Guards51Later Care52Care of Mature Trees53Pruning53Feeding55Spraying55WASHINGTONGOVERNMENT PRINTING OFFICE1920

WASHINGTONGOVERNMENT PRINTING OFFICE1920

BUREAU OF PLANT INDUSTRY.

William A. Taylor,Chief.K. F. Kellerman,Associate Chief.James E. Jones,Assistant to Chief.J. E. Rockwell,Officer in Charge of Publications.

Office of Horticultural and Pomological Investigations.SCIENTIFIC STAFF.L. C. Corbett,Horticulturist in Charge.

Truck Crop Production Investigations:

J. H. Beattie.F. E. Miller.C. J. Hunn.B. J. McGervey.

Irish Potato Production Investigations:

William Stuart.C. F. Clark.W. C. Edmundson.P. M. Lombard.J. W. Wellington.L. L. Corbett.

Truck Crop Improvement Investigations:

W. W. Tracy.D. N. Shoemaker.

Landscape Gardening andFloriculture Investigations:

F. L. Mulford.W. Van Fleet.

Bulb Culture Investigations:

David Griffiths.

Fruit and Vegetable Utilization Investigations:

J. S. Caldwell.C. A. Magoon.C. W. Culpepper.

Fruit Production Investigations:

H. P. Gould.L. B. Scott.C. F. Kinman.George M. Darrow.E. D. Vosbury.

Grape Production Investigations:

George C. Husmann.Charles Dearing.F. L. Husmann.Elmer Snyder.G. L. Yerkes.

Fruit Breeding and SystematicInvestigations in Pomology:

W. F. Wight.Magdalene R. Newman.

Fruit Improvement through Bud Selection:

A. D. Shamel.

Nut Investigations:

C. A. Reed.E. R. Lake.

Fruit and Vegetable Storage Physiology:

L. A. Hawkins.R. C. Wright.J. R. Magness.J. F. Fernald.

Extension Work (in cooperation with States Relations Service):W. R. Beattie.C. P. Close.

UNITED STATES DEPARTMENT OF AGRICULTURE

CONTENTS

THE COMFORT to be derived from shade trees has long been recognized. The early settlers of this country saved fine trees about their homes, on the village greens, along the country roads, and in the fields. Later, as villages grew, the householders planted trees adjoining their properties, and the result has been the beautiful elm-shaded villages of New England, the maple-shaded towns of New York and the Ohio Valley, and the oak-shaded streets of the Southeastern States. (fig. 1.)

With time, the villages and towns became cities, and the woodlands were largely destroyed. Conditions for tree growth were less favorable in the cities, and nurseries had to be depended upon for planting material. With these changed conditions the native trees of a region became less dominant in the city planting and were largely replaced by those trees listed in nursery catalogues which took the fancy of each property owner along the street. (fig. 2.) The quickest growing trees were considered first, and as some of these made a big showing the first few years and were easily transplanted, they have become the dominating trees in street planting from the Atlantic to the Pacific and from the Great Lakes to the Gulf of Mexico. (Figs.2,10, and13.) A few have planted better and more lasting trees (figs.1,3, and4); but the tree growth on the streets of the average town or city is ragged and unkempt in appearance, while that of the suburb or small village is not much better unless the planting has been done under municipal control and the plantings on a street have been confined to a single kind of tree.

P15311HPFig. 1.â€”An oak-shaded street in the South. Willow oaks in Birmingham, Ala., in late summer.

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Fig. 1.â€”An oak-shaded street in the South. Willow oaks in Birmingham, Ala., in late summer.

P18826HPFig. 2.â€”A street with mixed plantings. The trees are of different kinds, some unsuited for the purpose, planted at varying distances apart, according to the inclination of the property holders. A street in Stockton, Calif., photographed in early summer.

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Fig. 2.â€”A street with mixed plantings. The trees are of different kinds, some unsuited for the purpose, planted at varying distances apart, according to the inclination of the property holders. A street in Stockton, Calif., photographed in early summer.

P12515HPFig. 3.â€”American elms on a city street in midsummer. All these trees were planted at one time at uniform distances apart by the Commissioners of Washington, D. C.

P12515HP

Fig. 3.â€”American elms on a city street in midsummer. All these trees were planted at one time at uniform distances apart by the Commissioners of Washington, D. C.

The advent of such civilizing agencies as the telegraph, the telephone, the electric light, and the trolley car have added each its share toward the mutilation or destruction of the good trees that were in existence at the time of their coming. Faulty methods of pruning also have caused much disfigurement and ruin. (Figs.5and21.) To this mutilation has been added the unnecessary destruction of many trees in centers of business (fig. 6), because they excluded a little daylight, or made a store less prominent, or were somewhat in the way of using the sidewalk for merchandise.

In spite of all these troubles tree planting has continued because people love trees, enjoy well-shaded streets, and are willing to make efforts to get them. The trees on well-shaded streets are not only pleasing, but also contribute toward the health of the community by transpiring moisture into the atmosphere and by producing a restful effect on eyes and nerves. Red, especially, is known to have an exciting effect on human beings, and where city streets are well-shaded it makes less prominent those colors that might otherwise prevail and offend.

Fig. 4.â€”Trees 18 years old on adjacent streets:A, Pin oaks;B, ginkgos;C, Norway maples. Note the differences in size.

Good shade is so appreciated that its presence adds a value to adjoining properties. Real-estate men recognize this factor and plant shade trees as early as practicable on land which they develop. That the beauty of a city is improved by good street trees is becoming recognized more and more and is finding expression in the desire of garden clubs, civic improvement associations, and boards of trade for information on this subject.

P16692HPFig. 5.â€”A tree mutilated by linemen. An otherwise beautiful red oak in Louisville, Ky., as it appeared in midsummer.

P16692HP

Fig. 5.â€”A tree mutilated by linemen. An otherwise beautiful red oak in Louisville, Ky., as it appeared in midsummer.

Success in planting street trees can be attained only by planning and controlling the planting as a whole, by selecting the most suitable varieties, by securing trees in the best condition and planting them properly, and by giving the necessary later care.

While towns were small, conditions for tree growth favorable, and woodlands plenty, so that native trees were easily obtained and started, the practice of each householder planting his own trees as he saw fit gave good results. As towns became larger and impervious pavements took the place of earth roads, the conditions for tree growth became more severe and the results from the individual planting of trees less uniform. In large cities the conditions to be met are so extreme that it has become practically impossible for the average householder to grow street trees successfully, or to do so only at excessive cost. Then, too, a lineman in a few minutes often undoes what the individual has achieved with care and years of patient waiting (seefig. 5). The trees and the lines are both needed by the public, but when provided by individual initiative at private expense, but trimmed for the benefit of electric lines by employees of corporations intent on maintaining service at the least cost, the trees suffer unduly.

In order to have good shade trees at a reasonable cost which receive timely and efficient attention, with the effective control of wire lines, the care of the trees needs to be vested in some adequate authority.

Providing shade on city streets is as much a municipal function as providing lights or sidewalks and should, therefore, be cared for by public officials. All street trees should be directly under the care of duly appointed officers, who should be responsible for their planting and care, as well as for their pruning or removal. Negative control by requiring permits for planting, pruning, and removal is little better than no control.

P16986HPFig. 6.â€”A desert of asphalt in the business center of a city having less than 100,000 population.

P16986HP

Fig. 6.â€”A desert of asphalt in the business center of a city having less than 100,000 population.

The officials in charge should have the necessary authority and should be required to initiate and carry forward planting and all other needed work connected with the establishment and maintenance of street trees. Probably the most satisfactory way of securing supervision is through an unpaid commission of three or five members, which in turn employs an executive officer. In a small place a commission of three persons may be best, one being appointed every 2 years for a 6-year term. In large places five members may be better, and the ideal term would be 10 years. A compromise would be a 5-year term, a new member being appointed each year. The great need of long-term appointees is that it takes two or three years for a member of such a board or commission to see and realize the thingsneeded to be done and the policies that should be carried out. Because it takes a long time to get results in growing street trees, the policies should be as nearly continuous as possible and the terms of the members long enough to insure a majority of experienced persons on the board at all times.

The method of appointing the commissioners is not so important as that each shall be selected from the territory as a whole rather than from a part of it. In some places where the term of service is 10 years, each one's successor is appointed by the remaining commissioners, subject to confirmation by the court. Where this is done a member is not permitted to succeed himself. In other places the commission is appointed by the court; in others, it is elected by the city legislative body or is appointed by the mayor subject to the approval of the legislative body. The important point is to keep the administration as nearly as possible on a purely business basis.

A good board can accomplish nothing without liberal funds. There are two methods of providing these: (1) By an appropriation from the general tax levy and (2) by direct assessment against the properties, collectible with the other taxes. If the funds are provided by appropriation, a fixed minimum, expressed in millage of the tax rate, should be provided in the organization of the commission. This minimum should be such that a fair amount of maintenance work can be done when no other funds are available. Councils that appropriate money sometimes hamper boards by withholding appropriations. Work of the nature of tree planting should not be permitted to suffer or be lost by a year's neglect. The fund provided by this minimum amount should not be so large that regular additional appropriations will not be needed to carry on the work properly, as this will give a desirable point of contact of the commission or board with the ordinary channels of expressing public sentiment in the district interested. The minimum appropriation mandatory should be sufficient to prevent injury from lack of care of work already begun. A period of minimum care and attention while a board and the people or their representatives are coming to a new understanding of one another's position is not necessarily a detriment, provided a reasonable maintenance has been possible in the interim, but without such care the results are ruinous and work would better not be started than be undertaken with the possibility of such a period of neglect occurring.

It is probably desirable to assess the cost of tree planting against the adjacent property owners at a proportional cost per front foot and to provide for maintenance out of a general fund. Boulevards and other unusual developments are sometimes maintained with satisfactory results by regular assessments against the abutting properties.

After a proper governing board is provided, the securing of a competent executive is a matter of ordinary business procedure. It is usually desirable that he shall be not only a good executive but also a man with a knowledge of trees and trained in their care, so that he may be a competent adviser of the board as well as its executive.

P18857HPFig. 7.â€”Increased attractiveness due to trees on a city street, as shown by contrasting the two sides of the thoroughfare. If trees like red oaks, American elms, or the Eucalyptus in the distance had been used, the effect on this wide street would have been comparable tofigure 3. The trees in the left foreground are umbrella trees. Merced, Calif.; midsummer.

P18857HP

Fig. 7.â€”Increased attractiveness due to trees on a city street, as shown by contrasting the two sides of the thoroughfare. If trees like red oaks, American elms, or the Eucalyptus in the distance had been used, the effect on this wide street would have been comparable tofigure 3. The trees in the left foreground are umbrella trees. Merced, Calif.; midsummer.

With the help of one who knows trees and the local conditions to be met, the town should be studied and a suitable kind of tree selected for each street or for a large portion of a street (figs.1and3), and as conditions warrant the plan should be carried out as outlined. Mixed plantings of different sorts of trees (figs.2and7) are not as pleasing and effective as the use of a single species for considerable distances. The use of only one or two kinds for a whole town is likely to be monotonous, and it is also undesirable because the variety most used may become subject to serious disease or insect attacks. The species and varieties of trees suitable for city planting are few enough, if all are used, so an endeavor should be made to include as many different kinds as practicable, assigning one variety for a long stretch of street unless there is a marked change in its character, in which case a change of trees would be warranted.

Where trees are already on a street, the problem of planning for the future is frequently much complicated, especially if there are several kinds in good condition. Where there is but one good kind,gaps can be replanted with young trees of that sort. If there are poor trees of a good variety or trees of a poor or short-lived variety it would be advisable to remove these and do all the replanting at one time, so as to have the trees on the street as nearly uniform as possible. Where there are several good varieties in good condition the sensible thing is to care for the trees that are there and then, after careful study, decide on one variety for all future plantings on that street.

P14631HPFig. 8.â€”Trees 20 feet apart that should be at least 60 feet apart. Sycamores in Washington, D. C., as they appear in late winter.>

P14631HP

Fig. 8.â€”Trees 20 feet apart that should be at least 60 feet apart. Sycamores in Washington, D. C., as they appear in late winter.>

A common fault in all street planting is to put the trees too near together. (fig. 8.) This is more evident where the work has been done by the abutting property owners than by municipalities.

After trees are started and have attained some size it is extremely difficult to get them removed, even where the good of the remaining trees demands it. The removal of a fairly good tree merely becauseit is short lived in order to make room for a good one that will be permanent does not appeal to the average citizen. Where trees which have been planted by the property holder come under city control a strong feeling of proprietorship still remains, which is outraged by the suggestion of the removal of even poor trees. Where all the work is under city control good work is often hampered by a strong public sentiment against the removal of trees, even though they are poor or crowding.

Because of this difficulty it is extremely important that young trees be planted farther apart than at that time seems reasonable. If they are planted as far apart as is proper for mature trees the distance will be so great as to make planting seem a joke. If they are planted half the distance apart they should be when mature, good results would follow if the intermediate trees were removed when they nearly touch those to be left. As the intermediate trees would probably not be removed, or not until too late for the good of the remaining ones, planting had better be sufficiently far apart in the beginning to avoid the necessity of later removals. In the beginning the trees will be too far apart and when mature too close together, but it seems to be the alternative imposed by a misguided public opinion.

There is scarcely a community that would permit the removal of interplanted trees from a street of fine elms, oaks, or other worthy varieties without a protest that would be the almost sure political death of the administrative authorities responsible, no matter how great the need or how much expert support they might have. If short-lived intermediate trees were used they would not be likely to be taken out before they died, and they probably would not die before they had irreparably injured the permanent trees. The removal of surplus or interplanted trees can be made with least shock to the community by gradually narrowing the tree tops by severe pruning from year to year on the sides next the permanent trees until finally they are so narrow they may be removed and leave only small openings between the permanent trees. Even this method will not materially lessen the public protest at the final removal.

A common practice is to set street trees 35 feet apart. If it were practicable to remove one-half the trees at the proper time this would be a good distance, but in the eastern half of the United States and on the Pacific slope 50 feet apart is close enough for most varieties, and for the larger growing trees 60 to 70 feet would be better.

In order to grow, trees must have a soil of suitable texture, in proper mechanical condition, that contains sufficient available mineral elements and plenty of organic matter, and, last but not least, a constant supply of moisture and air. In addition to these there mustbe in active growth in the soil many forms of organic life that are in various ways preparing the material in the soil for the use of the larger plants. Not only must these things be present, but others that are deleterious must be absent, whether the substance is hurtful in itself or whether it is an excess of one that is otherwise beneficial.

Above the soil three things must be presentâ€”air, sunlight, and moistureâ€”and, as in the soil, harmful things must be absent in order to have success. Among the deleterious substances are sulphur and other fumes and soot and other products from incomplete combustion.

P14633HPFig. 9.â€”The irregularity in the size of the trees shown is due to a part of the first planting having been killed by illuminating gas from defective pipes. Norway maples as seen in Washington, D. C., in late winter.>

P14633HP

Fig. 9.â€”The irregularity in the size of the trees shown is due to a part of the first planting having been killed by illuminating gas from defective pipes. Norway maples as seen in Washington, D. C., in late winter.>

Some of the more obvious things with which a city tree has to contend are: Water-tight pavements, both on the sidewalk and street, that prevent the admission of air and water; the removal of the topsoil in street grading, thus forcing the tree to exist on the good soil provided in the hole; careless digging near the tree for gas, water, and electric service, and especially for the placing of curb-stones; the saturation of the soil with illuminating or sewer gas from defective pipes (fig. 9); the pouring of salt water from ice-cream freezers into gutters, where it may find its way into the soil near tree roots; the gnawing of the trunks by horses; and the cutting of the tops by linemen and tree trimmers.

Because of the uncongenial conditions for the growth of trees on city streets comparatively few kinds are satisfactory for such use.Among those available are some that will grow under extremely trying conditions. Kinds can be found that will thrive wherever it is suitable for human beings to live. If it is impossible to grow trees on a street, as a health measure that street should be closed for human use until conditions are so improved that it will support trees.

P15298HPFig. 10.â€”A business center relieved by a parking with Carolina poplars. Macon, Ga.; late summer.

P15298HP

Fig. 10.â€”A business center relieved by a parking with Carolina poplars. Macon, Ga.; late summer.

More kinds will thrive under suburban conditions where only a small portion of the roadway is covered by an impervious coating, where the parking spaces are liberal, and where the street is lined with open lawns than under the conditions in a city, where the street is covered with a water and air proof coating and the sidewalks with an impervious material, where parking spaces are limited, and where adjoining lawn areas are small or lacking. By a careful selection of kinds, all conditions in a city can be met. In some places bad conditions could have been improved greatly by a little forethought; in others, such conditions can be bettered. These details, like many other matters connected with city planning, have been ignored, but should be considered immediately, especially by villages and small cities.Figure 6shows how an opportunity for creating a beauty spot has been lost sight of, whilefigure 10shows how a city has utilized less ground to increase the comfort and attractiveness of its business center.

P15278HPFig. 11.â€”A street well proportioned in width of roadway, sidewalk, and parkings, with willow oaks on the left, American elms on the right, and young Carolina poplars near the roadway that should be removed. Columbus, Ga.; midsummer.

P15278HP

Fig. 11.â€”A street well proportioned in width of roadway, sidewalk, and parkings, with willow oaks on the left, American elms on the right, and young Carolina poplars near the roadway that should be removed. Columbus, Ga.; midsummer.

P14359HPFig. 12.â€”A street with too much pavement and too little parking space. Carolina poplars in Baltimore, Md., in midautumn.

P14359HP

Fig. 12.â€”A street with too much pavement and too little parking space. Carolina poplars in Baltimore, Md., in midautumn.

A common mistake in ambitious young cities and many old ones is to pave more of the width of the street for traffic purposes than, is likely ever to be needed. By reducing the roadway and throwing the remainder into liberal parking spaces much is added to the attractiveness and comfort of a city. A contrast in the two methods of treatment is illustrated in figures11and12. The recommendation that the roadway prepared for travel be made narrow is not to be interpreted as a reason for lessening the area dedicated to the public use; in fact, in most cities, especially in the northeastern quarter of the United States, too little space has been reserved from houseline to houseline (fig. 13). By reserving more room between the houses andthe street for use as lawns and gardens the conditions would be made more livable, opportunity would be offered for widening the public way without prohibitive expense if traffic or business demanded it, and the growing of street trees would cease to be a serious problem.

P16842HPFig. 13.â€”A street with too little room from houseline to houseline. Note the more attractive appearance of the side with trees. Norway and silver maples in Frederick, Md., in midsummer.

P16842HP

Fig. 13.â€”A street with too little room from houseline to houseline. Note the more attractive appearance of the side with trees. Norway and silver maples in Frederick, Md., in midsummer.

Compared with the whole number of trees used for ornamental planting, the number of kinds suitable for street planting is very small. For use under city conditions a tree must be adapted to the climate and to the soil upon which it is to be grown. It must have healthy foliage that withstands dust and smoke and a root system not easily affected by unusual soil conditions, by restricted feeding areas, or by root pruning when street improvements are made. The top should be in proportion to the width of the street upon which it is used, and it should be rather high headed or easily trained to that form and of open growth without being too spreading or sprawling.

Of minor consideration is the character of the foliage masses, whether dark or light, heavy and somber or open and airy, and also whether they have vivid autumn colorings. Only in the most southern parts of the country and in western California should evergreen trees be considered for street planting, and then only the broad-leaved evergreens, such as magnolias and live oaks. In the North the lack of sunshine during the short cloudy days of winter makes it desirable to admit all the light possible. Even in the South the question of sunshine should be considered when selecting varieties.

P125365HPFig. 14.â€”Narrow upright trees (Lombardy poplars) on a Barrow Conditions, it is better street. Washington, D. C.; midsummer.

P125365HP

Fig. 14.â€”Narrow upright trees (Lombardy poplars) on a Barrow Conditions, it is better street. Washington, D. C.; midsummer.

Narrow streets should be planted with columnar trees (fig. 14) or sometimes with small trees. Broad streets may be planted with spreading trees (figs.3and16), or, if provided with a central parking space, with moderate-sized trees in the center and on the sides, or with trees on the sides suited to the space and formal trees in the center. (fig. 15.)

P18856HPFig. 15.â€”Formal trees in a central parking, but appropriate trees wanting on the sides of the street. Canary Island date palms in Merced, Calif.; midsummer.

P18856HP

Fig. 15.â€”Formal trees in a central parking, but appropriate trees wanting on the sides of the street. Canary Island date palms in Merced, Calif.; midsummer.

As a rule, trees native to the locality that have been successfully grown in other cities should be given the preference. When a choice must be made between untried native trees and those tested in a city or town under different soil or climatic to give the native trees the first trial. There are many native trees that are promising which have not been planted on a sufficient scale or under sufficiently varied conditions to demonstrate their real value for street planting over any considerable area. Many of the trees mentioned in this bulletin may prove valuable far beyond the areas for which they are suggested. The burr oak, the swamp white oak, the scarlet oak, the chestnut oak, the white oak, the sour gum, and others may be found on further trial to be asvaluable as those already demonstrated to be valuable over large areas. Those mentioned have all been tested in a small way.

Caution should be used in selecting trees with conspicuous flowers and those with edible fruits or nuts, as in many parts of the country such trees are badly mutilated by the public. Even horse-chestnuts, although the nuts are not edible, are often broken by boys clubbing the trees. That public opinion can prevent such vandalism is in evidence all along the Pacific coast and at a few places in the East. Every effort should be made to create a sentiment that will protect these attractive additions to street adornment, but where the sentiment does not exist it is better to avoid the planting of such trees except in a limited way.

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