The elements of forestry, designed to afford information concerning the planting and care of forest trees for ornament or profit and giving suggestions upon the creation and care of woodlands with the view of securing the greatest benefit for the longest time, particularly adapted to the wants and conditions of the United States

Front matter

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Chapter I. Definitions

Forestry—Sylviculture—Arboriculture—Sciences inyvolved—-Trees-——A Species—A Genus—A Natural Order—Names used in scientific de- SRPMS ELO IAG: sow dan ctedicleai asc y vas cccs'ssideenaadieda'sesclegovets's daveueeseUeutewsemes 1-4

CHAPTER: i;

OF SOILS AND THEIR PREPARATION. EFFECTS OF SLOPE AND ASPECT.

Composition of Soils—Humus—Loam—How they affect the Growths of Trees—Silecious, Calcareous, Argillaceous, and Alkaline Soils—Color of Soils—How affected by underlying Rocks—Preparation for planting—Effect of Slope and Aspect—Degrees of Inclination....... 4-10

CHAPTER. Fit,

OF CLIMATE AND METEOROLOGICAL INFLUENCES,

Definition of Climate—The Atmosphere and its Elements—Oxygen— Nitrogen—Carbonic Acid Gas—Aqueous Vapor—Absolute and relative Humidity—Effect of Heat and of Cold—Dew—Fogs and Clouds —Rains—Effect of Woodlands—Evaporation— Percolation— Temperature of Soils—Winds—Agency of Water in Vegetation—Effects of Frost—Injuries from Snow—The Timber-line—Decline of Fruitproduction—Ruin from clearing off of Forests—Probable Effects in Wi CS beri eRRILOLUESS. > ccaesnccwas ssvedans «esedass ceatalen os quecietvessuseeare ee —eO

CHAPTER IV:

REPRODUCTION FRCM SEED.

The Blossom—Fertilization —Distribution of Tree-seeds—Dispersion by Winds, by Animals, by Water—FEarly-ripening Seeds—Gathering and keeping of Seeds, Nuts and Acorns—Germination—Time of sowing or planting—Vitalitv of Seeds..........cccceceeses Mighesswees 28-36 vi Contents.

CHAPTER V.

OF THE VARIOUS MODES OF PROPAGATION OF FOREST TREES,

Seeds planted where the Trees are to grow—Methods employed— Planting of Walnut and other Nut-Trees—Soaking of Seeds—Planting in Seed-beds and Nurseries—Spring and Fall planting—Propagation from Cuttings, Layers, and other Methods—Grafting...... 37-46

CHAPTER VI.

PLANiING CONTINUED.

Intervals between Trees—Planting in Rows, in Squares, in Quincunx Order—in Triangles—Number of Trees on given Areas—Necessity of close planting—Planting of young Trees from the Forests—Planting on the Sod—Planting without disturbance of Roots—Transplanting of large Trees—Disadvantage of planting of too large Size— Planting of Rocky Surfaces—Of mulching—Of thinning—Trimming and Pruning—Pollards—Removal of outer Bark—Arbor-days. 47-62

CHAPTER VII.

OF THE STRUCTURE AND FUNCTIONS OF THE VARIOUS PARTS OF GROWING TREES.

The Buds—The Leaves—The Wood and Bark—The growth of the

Trunk and Branches—Eccentric Forms of Growth—The Roots—The

pressure of Sap and its Changes—Autumnal Colors.............. . 63-79

CHAPTER VIII.

GENERAL VIEWS IN REGARD TO FORESTRY.

On the investment of Labor and Capital—Questions of Profit—The due Proportion of Woodlands and cultivated Fields—Forest Areas in Europe—Resemblances and Contrasts in Timber-Growth—General Glance at Forest Resources of United States and Canada—New England, Middle, Southern and Western States—Rocky Mountain Region—Pacific Coast—Canada—Great Britain—Alternations of Forest SEOW IR Gees oc snails sae. o's episntecton Thess daniel gees Rs See 79-91

CHAPTER IX.

ACTS OF CONGRESS RELATING TO TIMBER-RIGHTS.

Timber-culture Acts—Homestead Entry Act—Use of Timber by Railroad Companies—Privileges in certain States and Territories—Sale OF: VIMMOET ANAS. scices. xs0nce de veneetes anicdo stiaareneatewn aed yvaneamaen tine . 91-96

Contents. Vii

CHAPTER X.

EUROPEAN PLANS OF FOREST MANAGEMENT.

Method of Selection—Coppice-growth—W oodlands grown to full Maturity—European Forest Administrations—Schools of Forestry— Planting of Dunes—Reboisement—Checking of Torrents—Covering denuded Slopes—Plantations in Scotland.........cessseseeee cove 96-113

CHAPTER XI.

ORNAMENTAL PLANTING.

Pleasures and Benefits—II]ome-adornment— Village-Improvement and the planting of Waysides—City Parks—Rural Cemeteries—Grounds RIE Ge OELG LUISE UELONEE cance as tne mc owe cat nas sweneWasennss ciaages 113-127

CHAPTER XII.

HEDGES, SCREENS AND SHELTER-BELTS.

Hedges and Screens—Shelter-belts— Planting along Railroads—Planting On Russian Steppes.....ececesesseerseserseecereees hactaateatanasdaee 127-137

CHAPTER XIII.

CUTTING AND SEASONING OF WOOD. DEFECTS IN TIMBER. Proper Time for Cutting—Seasoning of Woods—Shrinkage—Strength of Wood with respect to Lines of Growth—Defects of Various ts are ape Reo AOR AOS Renita cae 137-144

CHAPTER XIV.

FUEL. CHARCOAL. WOOD-GAS.

Qualities desirable in Wood for Fuel—Charcoal—Table of Heating Qualities of Wood, by Mr. Bull—Modes of making Charcoal—Meilers or Coal-pits—Kilns—Red Charcoal—Distilled Products—I]luminat- We: W GO0-B9.8. ovaveniescevenne Sse Shan sake eamamanne nck ietaie fgatacce See 144-154

CHAPTER XV.

FOREST FIRES. ' Their Causes—Prevention—Control............ DEM ae Lice p tokiccorae anes 154-159

CHAPTER XVI.

PROTECTION FROM OTHER INJURIES THAN FIRES,

Pasturage of Woodlands—Injuries to Seeds and Seedlings by Wild Animals ecooeee earesseseecrancereoensD Geasee 2 Bevepeeee @er2ee0se280805000 89008898 159-161

Vill Contents.

CHAPTER XVII.

INSECT RAVAGES IN WOODLANDS.

General Statements—Etfect upon Wood-growth—Coleoptera—Orthoptera—H emiptera—N europtera—Lepidoptera — Hymenoptera -— Diptera—Insects that attack the Oaks—Elms—Hickories—Black Walnuts —Butternuts—Chestnut—Locust—Maples—Cottonwoods— Poplars—Lindens—Birches—Beech— W illows—Pines—Spruces— Firs— Hemlocks........ eee soy usepatm ere sapesebannea stetusywen cere cuacse ciel 161-187

CHAPTER XVIII.

PROCESSES FOR INCREASING THE DURABILITY OF TIMBER, OR FOR IMPROVING ITS QUALITY.

General Statements—Causes of Decay—Charring—Immersion in Water —Penetration of Liquids, and of Solids in Solution—Oils—Crude Petroleum—Salt—Incombustible Wood—Alum — Borax — Lime — Processes of Bethell—Boucherie—Burnett—Carey—Hatsfield—Kyan Margary — Payne — Prescott — Robbins — Tait — Thilmany — Re- CUE, acacia osttniene wars eenseecgunnteees tecesuerfannbve-acneeeitae seo seat 187-199

CHAPTER XIX.

RESINOUS AND OTHER PRODUCTS OF CONIFERS.

Naval Stores—Turpentine—Spirits ot Turpentine—Rosin—Methods of Resinage—Economy and Waste—French Methods with the Maritime Pine—Tar—Pitch—Lamp-black—Canada Balsam—KEssential Oils— Perfume from Pine-sap......... ide nea se peauedeceenneeeee coenatedandane 199-205

CHAPTER XX.

USE OF WOOD IN THE MANUFACTURE OF PAPER.

Mechanical Processes of Vélter, Hartmann, Siekricht, ete.—Chemical Processes—Cultivation of Poplars for Paper Pulp.............. 205-206

CHAPTER XXI.

TANNING MATERIALS,

Supplies from the Oak—Hemlocks, ete.—Tanning Extracts—-Management of Oak-Coppices—Peeling by the Aid of Heat—Sumac. 206-210

Cont: nts. ix

CHAPTER XXII.

DESCRIPTION OF PARTICULAR SPECIES.

Oaks—Chestnuts—Beeches—Birches—Alders—fornbeam— Maples — Box-Elders—Lindens—E]ms—Osage-Orange—Mulberry—H ackberry —Tulip-tree—Sycamores—Buckeyes—Soap-berry— Locusts— Coffee-tree—Red-bud—Acacias—Y ellow-wood— Pears and Apples —Crabtrees—Plums and Cherries—Thorn-trees—Service-berry—E ucaly ptus —Eugenias— Cornel Family-—Sour-Gum— Elders— Elms— Butterbush—Silver-bell—Ashes—Olive—-Lilac—Hickories— Black Walnut Butternut—Poplars—Cottonwoods —W illows —Ailanthus —Arbutus —Manzinita—Paw-paws—Catalpas —Mountain Mahogany— Persimmon—Burning-Bush— Holly Family— Laurels—Sweet-Gum— Magnolias—Pride-of-India— Iron-woods— Sorrel-tree— Mesquits— Buckthorns — Sumacs — Sassafras — Buffalo-berry — Mahogany —Arrow- LAIST a ae eee 210-299

CHAPTER XXIII.

THE CONIFERS.

General Statement and Definitions—Classification—Cypress Family— Yews—Families not represented in U. S.—Pine Family—The Cypresses and White Cedars—The Junipers—Red-Cedars—Bald-Cypress —Sequoias—Giant-trees—Red wood — Yews — Torreyas — Gin kgo— Pines—Spruces—Hemlocks—Douglas Fir—Firs—Larches... 299-345:

CHAPTER XXIV.

TREE-PLANTING IN KANSAS AND NEBRASKA,

List of Species approved in Kansas, by Counties—Propagation by Cuttings and Native Seedlings—Distances between Trees—Effect of Shelter-belts—Locust-trees in Central Kansas—Gathering and Pre= serving Seeds—-Preparation of the Ground—Tree-culture on the RMLs Meats hse ses aden nas oc Toei eile hosel eR adieu oe vues chonne 346-353

Recent Decision under Timber-culture ACt.......2,0c0seeseeececeeeee 304 eee dl fo Pe Ss ia Pritras P Pee eee kL OF a) l 7

ELEMENTS OF FORESTRY.

CHAPTER I.

DEFINITIONS.

1. Forestry, in its most comprehensive sense, is that branch of knowledge that treats of woodlands—their formation, maintenance, and renewal, the influences that may affect their welfare ; the methods employed in their management, the removal, preparation, and use of their products, and the economies that may be gained by skillful operation.

2. Sylviculture! is that part of Forestry which relates to the planting and cultivation of groves and collective bodies of forest trees.

3. Arboriculture’ treats of the cultivation of trees. It is sometimes limited to the cultivation of fruit-trees, but the term may properly be extended to include the planting and care of trees generally, whether for fruit, ornament, or other use.

4, Forestry involves the application of many branches of science:

(a.) From natural history it derives the description and classification of trees, and of the animal and vegetable life that affect their welfare.

(6.) From geology and mineralogy, it learns the origin and composition of soils and sub-soils, and of the rock formations from which they are derived, their constituent parts, their permeability, and their fitness for the successful growth of particular kinds of trees.

(c.) By the aid of chemistry it determines the elements of the soil, the composition and changes that take place in the growth and decay of wood, the methods that may be used for increasing its durability or improving its quality, and the various operations concerned in the production and use of its chemical products.

(d.) From mathematics it derives aid in all processes of measure-

(1) From sylva, “a grove.” (2) From arbor, “a tree.” (1) 4

2 Definitions.

ment and calculation concerned in forest lands, materials, management, working, or revenues.

(e.) From mechanics, it applies the various agencies employed in cutting, transporting, and manufacture of wood and timber in every form.

(f.) From physics and meteorology, it determines the various questions of atmospheric influence and of climate that may arise, whether as cause or effect, and seeks to learn how these may be improved to best advantage, and, in some cases, controlled.

(g.) From political economy, it applies the principles that determine questions of supply and demand, of public policy, and of financial profits, the interests that are involved, and their mutual dependence, the laws of trade, as they concern forest products or properties, and whatever principles may relate to their creation, production, or management.

5. An intelligent system of Forestry aims to impart knowledge as to the conditions best adapted to cultivation, the best methods of securing a growth of trees by seeding or planting, the use of measures that shall secure their thrifty growths, protection from injuries, natural renewal at period of full maturity or time for use, and a constant tendency toward improvement of the products.

6. A Tree, isa plant having a woody root, trunk, and branches. We generally apply the term shrub to trees that are less than fifteen feet in height at maturity, and the term bush to those that grow to six feet in height or less. These terms are however arbitrary, in their use, and can not be with certainty applied to any species.

7. Trees may increase from within, as in the case of palms, or by the deposit of wood in annual layers. under the bark. The former have no bark proper, and are called Endogenous, a term signifying ‘‘orowing from within.” They are represented in the Southern States by the palmetto (Sabal palmetto), and a few other species, but on account of their slight relative importance as forest trees, they will be no further noticed in this work. The latter are termed Exogenous, a term signifying ‘‘ growing from without,” and increase by the deposit of new layers of wood on the outside, under the bark. This great division includes, with the above exception, all of the native and naturalized trees of the United States.

8. A Species, when used in Forestry, is understood to mean a group of trees or other plants, resembling in the details of their structure,

Definitions. 3 and producing the like forms of growth from their seeds. They are subject to many variations, due to differences of soil, climate, and other causes, and occasionally produce unusual forms in their leaves, size and color of flowers, quality of fruit, or habits of growth, which are called ‘‘ sports.” In other cases, hybrids will form by cross-fertilization, the result being a tree that partakes of some of the characteristics of both species. This is occasionally seen in the oaks and the willows, but asa rule the species remain distinct. These deviations from the normal type may be perpetuated by budding, grafting, or layers, but when they bear fertile seeds, they do not produce plants having like peculiarities, and tend to return to their original forms.

9. A Genus, is usually a group of species having common resemblances in the structure of the flowers and fruit, and generally, in their leaves and in the habit of growth, such as the pines, maples, birches, ctc. In some cases, however, a genus may include but one species. They are sometimes divided into groups or sub-genera,. having some common resemblance, and occasionally these may be further arranged into other groups, having common forms or properties. Where there are several species in a genus, they may be generally grafted upon one another, but in other cases this can only be done successfully within the group or sub-genus to which the species belong.

10. A Natural Order, in botany, is a class of trees or plants that usually embraces several genera, having a common resemblance in the structure of the seed and fruit and in manner of growth, differing from all others and constant within itself. These are again sometimes divided into sub-orders, families, or groups, depending upon a common resemblance, and instances occur in which a natural order includes but a single genus.

11. We have examples of natural orders in the Coniferw, embracing the pines, firs, spruces, cedars, junipers, etc., and in the Leguminose, or bean-like fruited plants, which include, among trees, the locusts, honey-locusts, acacias, Kentucky coffee-tree, and many others.

12. The description and classification of orders, genera, and species among trees form a part of the province of botany, and will not be attempted in this work. In mentioning the common names

4 Of Soils, ete— Humus.— Muck.

of trees, we shall generally give with them their scientific or botanical names, as a means for more exact designation.

13. The common names are very uncertain, and may in one region be applied to species very unlike those where they are used in unother. But the scientific names, rightly applied, are exactly understood in every language in which the sciences are taught, and can not be mistaken for any others. They are very generally derived from Greek or Latin words, expressing some quality or character in the genus or species to which they are applied. The generic name is more commonly derived from the Greek, and the specific name from the Latin. The former always begins with a capital letter—the latter only when it is derived from a proper noun. Where a number of species are mentioned in succession, the initial letter only of the genus will be used after the first one, as Pinus strobus, P. mitis, P. rigida, ete.

Chapter II. Of Soils And Their Preparation—effects Of Slope And Aspect

14. The soil or loose material that generally covers the surface of the earth to a greater or less depth, partakes in a large degree of the chemical character of the rock formations from which it has been derived. These may be the subjacent rocks, or the material may have been transported by former geological agencies, as in “drift,” or deposited by those now in action, as in alluvial mud, or littoral sands.

15. Besides these mineral components, the soil generally contains more or less organic material, derived from vegetation, or, to slight extent, from animal life. In the native forests, this ‘‘ vegetable soil” has been mostly created by the trees and herbage, from materials taken up in solution by the roots from the soil, and absorbed by the leaves from the air, and has gradually accumulated from the decay of the leaves, or of the trees and plants themselves.

16. This organic material is called humus, and its quality and amount depends upon the kind and quantity that has been allowed to decompose. It is sometimes known as ‘“ vegetable mold,” and has no definite chemical composition, but contains Humic acid (C,,H,,0,), and various other organic compounds. When vegetation decays in moist places, as in swamps, it forms muck, and

Peat.—Loam.—Functions of the Roots. 5 in some situations peat. These vary considerably in composition, and the latter contains so large an amount of carbon that it is used profitably as a fuel. The former, when mixed with animal manures, and the latter, when its acidity has been neutralized by lime or alkalies, become valuable as fertilizers. Both humus and peat absorb water with avidity, and retain it with tenacity. It is partly on this account that vegetable mold, when mixed with other soils, tends to impart fertility by retaining moisture within the reach of vegetation.

17. The term Loam is attached to a class of soils composed of different earthy materials of dissimilar particles, not easily ductile, readily diffused when thrown into water, and easily penetrated by the roots of trees and other plants. A mixture of humus renders it porous and fertile, and in a forest, this fertility tends constantly to increase, and hence the growth of trees is one of the best means for restoring exhausted soils.

18. The soil has an influence upon the growth of trees in two ways: it gives them support, and it furnishes them with nourishment. In order to give support, the soil should be permeable by the roots, without being too tenacious to resist their extension, nor too light to hold them. In nursery plantations, the proper qualities may be secured by artificial mixture of materials, but except in a very small degree, we can not modify them, and must seek to improve by the choice of species, the conditions as we find them.

19. As the roots of trees penetrate much deeper into the soil than those of agricultural plants, the welfare of woodlands often depends much upon the depth and character of the sub-soil, as is observed in the ‘‘ Landes” of south-western France, where a vigorous and profitable growth of trees is obtained upon lands that are almost utterly barren for cultivation in farm crops. In other cases, as in flat limestone districts, the surface soil may be too thin for cultivation, while in the fissures there is sufficient soil for supplying the roots of trees. These roots, when they decay, besides leaving the organic material of which they were composed, also leave open passages penetrating deeply into the soil, and affording opportunities for drainage. These may become filled in with mold from the surface, and thus they in some degree assist in rendering the soil fertile toa greater depth than would be possible from the simple deposit of organic materials upon the surface. .

6 Classification of Soils.

20. The state of division of the soil, as to whether coarse or fine, has also an important influence, especially with reference to its permeability by water, its drainage, and the like. Upon these properties, and the organic materials, in connection with the local climate, the fertility of a given soil may be said to depend.

21. It matters not what the chemical or physical properties of the soil may be, it will remain unproductive unless there be seasonable and sufficient rains, or their equivalent supplied by irrigation, and unless the conditions of temperature be consistent with vegetable growth.

22. Although soils present infinite variety in their constituent parts, they may be classed under four principal divisions, viz.: siliceous, calcareous, argillaceous, and alkaline.

23. In siliceous soils, the principal constituent is gravel or sand, composed of silex or quartz, more or less finely divided, and nearly or quite destitute of the power of absorbing of retaining water, unless underlaid by a retentive sub-soil, or unless it is but moderately above the level of a standing water, from which, by capillary attraction, its moisture may be drawn.

24. In calcareous soils, the carbonate of lime is found, either from the decomposition of limestones, or from marls of more recent organic origin. Such soils have the property of absorbing and retaining moisture in a high degree, but, although saturated they do not become impenetrable to the air, and when turned up and exposed to its action they fall to dust, and this the more readily when assisted by frost. They will effervesce when thrown into acids, and this affords a convenient, but not absolute test.

25. In argillaceous soils, the silicate of alumina, in the form of clay, forms the principal ingredient. These soils have a strong affinity for water, and hold it with great tenacity; yet, when exposed to solar heat, they crack into deep fissures in times of drouth. The water that falls upon clay soils does not penetrate, and they often afford much resistance to the roots of plants.

26. In alkaline soils, the soluble salts of soda are in excess. Where these soils occur, there is a noted deficiency in the rain fall, and a marked sterility from this cause, for the excess of alkali appears principally due to the want of moisture for dissolving it out and carrying it away. When such soils are irrigated, they become fertile, and improve as the excess of alkali is reduced, A lime-like deposit

Characteristics of Soils. 7 is found in hollow places where this soil prevails, and the sage-bush (Artemisia tridentata) and grease-wood (Sarcobatus vermiculatus) form the principal vegetation.

27. Although none of these soils can alone be called fertile, their proper mixture, and especially of the first three, with humus, affords conditions highly favorable to success.

28. Besides the qualities resulting from their chemical composition, and their relations to moisture, soils differ greatly in their capacity for absorbing, retaining, and radiating heat. A soil covered with siliceous pebbles retains the heat better than fine sand, and hence it is one of the circumstances that favor the growth of the vine. In the wine districts of France, differences in the time of maturing the fruit have been traced directly to this cause. A sandy soil radiates heat very readily in clear summer nights, and frosts injurious to vegetation are more apt to occur upon these soils, where exposed.

29. The color of a soil has much effect in determining absorption of solar heat. If dark colored, it becomes warm sooner and to a greater depth and degree than if light.

30. The character of the underlying rock itself has also its influ-

ence upon the growth of plants and trees. If siliceous and solid, their roots get no nourishment and no hold. If friable and composed of mineral elements that may be taken up in solution by the roots, their fibers will insinuate themselves into the fissures and assist the disintegration, especially where moisture is present, and where the frost can act. This operation takes place more readily where the rock is stratified in thin layers that are highly inclined. _ dl. It isa fact familiar to geologists that certain forms of vegetation, and especially of trees, are characteristic of the rock formation that underlies them. We have examples of this in shales rich with potash, that are congenial to the elms. A limestone soil is favorable to the maples but not to the pines, while the latter flourish best on siliceous soils, if suitably mixed with other ingredients. A line of outcrop of some rock formation upon a hillside may be made known in some cases conspicuously by the color of the foliage of the trees that grow upon it, especially when they are colored in autumn or remain green in winter.

32. The soil upon a sloping surface is generally deeper, more humid, and richer near the foot, and tends gradually to become thin,

8 Of the preparation of Soils.

dry, and sterile toward the top. These differences become greater as the inclination is more steep. Upon such slopes, it becomes highly important that the surface should be covered with vegetation and consolidated by its roots. There is no growth so favorable for this purpose as that of trees, and elsewhere we will notice the disastrous results that have followed from their clearing off upon steep mountain sides. In some cases, the damage is beyond remedy, while in others it may be arrested and utility restored.

Of the preparation of the Soil for sowing or planting Forest Trees.

33. In preparing land for a grove or woodland, the soil should be thoroughly mellowed by previous working or cultivation. Upon new prairie land there is but little chance of success in starting a successful growth of trees until the sod has been turned over and thoroughly rotted. This can best be done by cultivating at least one or two years previously with some farm crop.

34. The first breaking up of the sod can only be done to advantage in the season when vegetation is most active, and it varies somewhat in different years and in different localities. It may be generally said to last through the month of June, and it sometimes may continue longer. Toward the latter part of summer and in autumn, the soil is too dry and hard for breaking up, and the herbage does not so readily decompose. The first furrows must be broad and thin. The subsequent plowing should be deeper, and the soil should be rendered perfectly mellow by harrowing.

35. For windbreaks and hedges, this preliminary work may be in the line of proposed planting, and at least four feet wider than the intended borders.

36. In the planting of trees for avenues, the soil near the surface, which is generally more fertile, should be placed by itself, and this should be the first that is used in covering the roots. In hard clay soils, there is an advantage in preparing the holes in autumn, and leaving them to the action of the air and the frost through the winter, in readiness for the next spring.

37. It is sometimes necessary, and often advantageous, to fertilize at the time of planting, and the best material that can be used is well-rotted leaf-mold from the woods. It may be first mixed with the soil that is spread next to the roots. Where stable manure is used, it should be placed near, but not in contact with the roots, or it

Slope and Aspect.— Northern and Eastern Aspects. 9 should be used as a top-dressing. In the common practice of forestry, and at present prices of labor and of timber, we can not usually do more than to sow or plant the species that appear to be best suited to the conditions, and we can only fertilize in nurseries and special plantations. It is not improbable that methods of tertilization upon an extensive scale may hereafter be employed in forest planting, and with profitable results.

Of the Slope and Aspect of Surface, and their Effect upon Tree Growth.

38. The slope of a surface is sometimes inentioned in degrees of the angle that it rises above the level. It may be called a gentle slope, if under 10°; somewhat steep, if from 10° to 20°; steep, if from 20° to 34°; and very steep, if from 35° to 45°. :

39. The aspect or direction of a slope is found to have a perceptible, and often a notable influence upon tree growth, and this effect is greater in proportion to the extent of surface. Upon isolated swells of land and small hills, it might be scarcely noticed, but on the opposite sides of mountain ranges, or in mountain valleys, it may be very great.

40. A northern aspect receives no full sunlight, or its rays fall obliquely in the morning or toward evening, according to the angle of elevation. The winds are colder and dryer, but in the growing season generally not strong. The soil retains moisture, and the growth is often rapid. The trees retain their regular shape, and the wood is softer, not as strong, but generally well adapted to manufacture. As vegetation is a little delayed, the spring frosts are not so apt to do harm, but from the late and imperfect hardening of the new wood, the frosts of winter may doinjury. As the snows lie longer on these slopes, the forests are benefited by their delaying the growth in the first uncertain warm days of spring, and by the moisture that they retain. The starting of forests by seeding is more easily secured on a north slope than any other, and it is only upon this slope that forest-tree seeds are sown upon the damp snows in starting mountain forests.

41. An eastern aspect receives the sun in the cool morning hours, when the temperature and light are moderate. The winds in our Atlantic States are often damp, especially in winter. The soil retains its moisture fairly. Timber grows well, and acquires medium qualities that adapt it to the greatest variety of uses.

10 Southern and Western Aspects.

42. A southern aspect receives both the heat and light with greatest intensity, and is more liable to winds and storms, and the soil to erosion from rains, than any other. The trees, on the whole, are of slower growth, owing to deficient moisture, and are less regular in form, but the wood is firm, heavy, and strong, well adapted to all uses where these qualities are required. Seeding can seldom be secured on a steep southern aspect in a warm, dry climate, and trees must be set from nurseries and attended with greater care. The south side of a mountain is much more likely to be bare than any other, every thing else being equal.

43. A western aspect receives the sun obliquely, but in the warmest part of the day, and in our Western States, vegetation is most exposed on these slopes to drying winds. The soil is apt to become dry, and timber is therefore of slower growth and less regular in

form, but in the main good.

44. These differences from aspect are more noticeable in elevated regions than in low grounds, and they depend in degree more or less upon the nature of the soil, and local climatic influences that may determine the direction of the surface winds, or otherwise affect the location.

45. The degree of inclination has also a notable influence upon vegetation, and on the action of rains upon the surface. If less than one in six, the conditions are generally good. From this to one in three, agricultural cultivation becomes difficult, and the surface is liable to wash; still, the roots of trees can find a hold, and, if they can get deep into the soil, forests will prosper. At still ereater angles, cultivation becomes difficult without terracing, and the dangers from erosion become greater. Upon such extreme slopes, pasturage is apt to cause great injuries by destroying the herbage and allowing the soil to wash into the valleys. The true policy should be to keep them covered with woodlands, if possible, and to clear by selection. never exposing the whole surface at once.

Chapter III. Of Climate And Meteorological Influences

46. We understand by climate, the atmospheric conditions of a given region, resulting from its latitude, elevation, temperature,

The Atmosphere and its Elements. tH humidity, amount and distribution of its rains, character and force of the winds, intensity of light, and other general or local causes.

The Atmosphere and its Elements.

47, The atmosphere from which the trees, through their foliage, derive a part of their aliment, and to which they return certain gaseous elements in the process of growth, consists of about one part of oxygen to four parts of nitrogen by volume. It always contains, besides these, a nearly constant proportion of carbonic acid gas, and a variable amount of aqueous vapor.

48. Oxygen. This gas is necessary to the existence of all animal and vegetable life, and to combustion, respiration, fermentation, and many other processes of nature. It has a wide range of affinities, and forms a part of all organic and most mineral compounds. It is absorbed or disengaged in various operations of tree-growth, and, under certain conditions, it hastens decay.