SD 373 .P65 Copy 1 LlBROfJy 002 S18 I SD 373 .P65 Copy 1 COMl'XTS. The life of a tree 5 The I larta c )f a t ree (i The food of a tree 7 The composition of wood .S How the tree breathes t~. 8 Transpiration !) The growth of a tree 9 Tlie structure of wood 11 Atuiual rings lo Heart wood and sapwood 13 Trees in the forest 14 The various requirements of trn-s If) Re(]uirenieuts of trees for heat and moisture , IH Re(]uirements of trees for liglit 17 Tolerance and intolerance IS The rate of growth 19 The reproductive powi'r of trees 'M Pure and mixed forest -! 1 Reproduction by sprouts T.i The life of a forest '2',i A community of trees 23 The life of a forest crop '2b The seven ages of a tree 2(5 How the crop begins 2(5 The forest cover established 27 The 1 leginning of the struggle 27 (4n iwt h in height 2S The struggle continued 29 Natural pruning 29 The culmination of growth .'Jl The end of the struggle 31 Deatli fr< mi weakness and decay 32 Destructive hiiubering 34 Conservative lumbering 34 Enemies of the forest 35 Man and nature in the forest 35 Grazing in the forest 35 Grazing and tire 3t> Trampling 37 Browsing 37 Forest insects 38 Forest fungi 38 Wind in the forest 38 Snow in the forest 40 Forest fires 41 Historic forest fires 42 Means of defense 43 Surface fires 44 Ground fires 45 Back firing 46 Fire lines 47 ILLUSTRATIOXS. Page. 1. Roots, stem, and crown of ii young 81icll)iark lli<'k(iry 5 2. Upturned skeleton roots of a Red Fir 6 3. Trunks of two Red Firs 7 4. Stem and crown of a Longleaf Pine 7 5. Cross section of wood and bark of the Western Yelli>w Pine 9 6. Yearly growth of a branch of Horse Chestnut 10 7. Perpendicular cut of wood and bark of the Western Yrllo much alone in early youth 30 22. I )iagram to show why a sharply conical crown receives mcire light than a flat one 32 23. Young growth under old trees 33 24. Destructive lumbering in the Coast Reflwood Belt 34 25. Band of sheep in a forest reserve .36 26. A windfall in the Olympic Forest Reserve 39 27. .\ young spruce loaded with snow 40 28. The rotting stubs of fire-killed veterans of Red Fir 41 29. A surface fire burning slowly against the wind 44 30. The effect of repeated fires 45 31. The result of recurring fires 46 32. Setting a back fire on the windward side nf a road 46 33. A fire line along a railroad 47 4 A PRIMER OF FORESTRY. The object of forestry is to discovi iiig to which forests lire hest nuiti- iiued. It is distinct from arbori- culture, which deals with individual trees. Forestry has to do with sin- gle trees only as they stand together on some large area whose princi})al crop is trees, and which theret'oic forms part of a forest. The forest is the most highly organized portion of the vegetable world. It takes its importance less from the individual trees whicii lielpto form it than from tile qualities which belong to it as a whole. Although it is composed of trees, the forest is far more than a collection of trees standing in on(> place. It has a population of ani- mals and plants peculiar to itself, a soil largely of its own making, and a climate difl'erent in many ways from that of the open country. Its influence upon the streams alone makes farming possible in many regions, and everywhere it tends to prevent floods and drought. It sup- plies fuel, one of the flrst necessaries of life, and lumber, the raw material, without which cities, railroads, and all the great achievements of mate- rial progress would have been eithei- long delayed or wholly impossible. The forest is as beautiful as it is useful. The old fairy tales which spoke of it as a terrible place are wrong. No one can really know the forest without feeling the gentle influence of one of the kindliest and THE LIFE OF A TREE. andap])ly the print'iples accord- Fi'. 1. — ILodtH. stum, jiiul crown of a : Hliullbark Hickory. strongest parts of natui'e. Fi-oni ('\'ery point of view it is one of tlie. most helpful friends of ni;iii. Pcihaps no other natural agent has done so nuich for the human race ami has ht'cn so i-ecklessly used and so little understood. THE PARTS OF A TREE. In order rightly to understand the forest, something must first be known about the units of which it is made up. A tree, then, is a wood}- plant gi'owing up from the ground usually with a single stem (tig. 1). It consists of three parts: (1) The roots (tig. 2), which extend into the ik iK.li 1 suilln tliL In I ill r I \ I nil Mupit Pc-inuiuli \\asliiiiirtci ground to a depth of y> or 4 feet, or still farther when the soil is not too hai'd and they do not find moisture enough near the surfaet^; they hold the tree in place and take up from the soil wat(n-and cei-tain min- eral substances which the tree needs in its growth; (2) tlie trunk or stem (fig. 3), which supports the crown and supplies it with mineral food and water from the roots; (3) the crown itself (tig. 4), with its network of branches, buds, and leaves, in which the food taken up by the tree from the soil and air is worked over and made ready to assist in the growth of the whole plant. The crown has more to do with the life of the tree than its other parts, for the most important pi-ocesses in the r(>production of tiie tree and the digestion of its food take place in the crown. For this reason, and hecuuse we can control its shape and size more easily and directly than tliut (if th(! roots or trunk, the crown is of special interest to the forester. 1 1 is idniost exclusively with the crowns that he has to deal in tcnilini^- a rr(i[) of trees and jii-ejiarinj^- the way for tiie sut'ceedino' M ^ ^^mm «?> ylifSL ""^^HJIH KH^ ''H^^Km m j ^'^Jk^p^W^fj^ ^ -",i^- nj ^^1^ w ^^S^ K - J w ^ ^^m^^^hm^t' I'^ll^ro^EI fet ^ iHB^Ki^^]^*^ «i ^^ ^^fe-'ir^ Fig. 3.— Trunks of two Red Firs of great size. Olympic Forest Reserve, Wash- ington. Flu. \. — Stem aiul crown (if a Longleuf Pine, the latter covered with moss swaying in the wind. yciieratidii. .\s they stand together in (lie ftirest. (he crowns of the trees form it broken .shelter, which is usually spoken of as the leaf CUIK ipv, hut which may better be called the coyer. THE FOOD OF A TREE. The materials upon which a tree feeds are derived from the soil and the air. The minute root hairs which spring from the rootlets tuke up water from the ground, and with it vtirious substances which it 8 holds in solution. These sire the earthy constituents of the tree, which reappear in the form of ashes when any part of it is burned. The water which contains these materials goes straight from the roots to the leaves, in which a most important process in the feeding of the tree takes place. The process is the assimilation or taking up and breaking up, by the leaves, of carbonic-acid gas from the air. It goes on only in the presence of light and heat, and through the action of chlorophjdl, a substance from which the leaves and the young bark get their green color. Plants containing chlorophyll are the chief means l)y which mineral materials are changed into food, so that nearly all plant and animal life depends upon them. Plant cells which contain chlorophyll t)reak up the carbonic-acid gas with which they come in contact, retain the car- bon, one of its elements, and .send back the other, oxygen, into the air. Then, .still under the influence of the sunlight, they combine the carbon with the oxygen and hydrogen of the watei' from the roots into new chemical compounds, in which nitrogen and the earth>' constituents mentioned alwve are also present; that is to sa}', the food materials which reach the tree through the roots and leaves are first digested in the leaves somewhat as food is digested in the human body, and are then sent to all living parts of the roots, stem, and crown, where thej' pass through another process of digestion, and are then either used at once in growth or stoi'ed away until the propei' moment arrives. This is the general rule, ]>ut it is believed that in some cases food taken up l)y the roots can be used without first being digested in the leaves. THE COMPOSITION OF WOOD. Wood is made up chiefly of carbon, oxygen, anil hytlrogen. ^\^hen perfectly dry, about half its weight is carbon, and half oxvg of the deep cracks in the bark, at the bottom of which lenticels an- placed. THE GROWTH OF A TREE. The addition of new material in the way descril)ed in the preceding pages is the foundation of growth. Except in the buds, leaves, fruit, and the twigs le.ss than a year old, this material is deposited in a thin coat over the whoie tree between the wood and the bark. The new 10 twigs grow in length by a kind of stretching, ])ut only during the tirst year. Thus it is oidv l>v means of these youngest twigs that a Fiu. G. — Yearly ijrowlh of a brunch ui" Hur^L' (;:liL'slmit. Tin.' haml-s uf wrinkles mark the divisions between the growths of fonr snccessive years. The (iistnnce between these baitds would never have been greater thaii it was when the branch was cut. FUi. 7— E'erpeudiciihii bark into scales by II and bark. be division ()f the tree increases in height and in spread of branches. After the tirst year their length is fixed, younger twigs stretch out from the buds. 11 and the older ones grow henceforth only in thickness (tig. 6). The fresh coat of new material mentioned above covers them year })v year. There are two layers in this coat, s<^parated hy a third one of tender forming tissues called the cambium, in which the actual making of the new substance goes on. The inner sitU' of the cambium layer forms new wood, the outer side new bark. Besides the ti'ue cambium, which forms both wood and bark, there is another cambium which makes the corky outer bark and nothing else (tigs. 7 and S). This cork cambium mu\' (Micircii^ the whole tree, like tlie true caml>ium. as in the lied Cedar, oi- it may foiin little s('i);irate films i either casi' it dies from time to time and is rc-fDniu the l)ark. but in ni^arer the wood. THE STKUCTURE OF WOOD. Wood is chiefly made up of very small tul)cs or cells (tig. 9) of vari- ous kinds, which have special uses in the life of tlie tree. Some con- duct water from the roots to the crown, some store away digested food, and others merely strengthen the structure of the ^v•ood and hold it togetiier. The wood of cone-bearing or coniferous trees (like the pines and spruces) has but few kinds of cells, while that of the broad- leaf trees (such as oaks and maples) is much less simple. But in each case some of the cells have thick walls and small openings, and others wide openings and very thin walls. In climates which have regularly one season of growth and one of rest, like our own, the cells of the 12 r r^c <0 H r layer of new wood formed each year at the inner surface of the cam- ])iuni are arranged in a definite vfny. When growth ))egins in the spring, and the fresh twigs and leaves put out, there is a great demand for water in the crown to supply these moist green new parts of the tree. Water rises in most trees through the newer layers of the wood, and especiall}' through the last ring. Consequently, at first the tree makes thin-walled cells with wide openings, through which water can rise rap- idly to the ends of the branches. Later on, when the demand for water is not so great, and there is plenty of digested food to supply l)uilding material, the cells formed are narrow '^' [_^V^_ rC^CrV ■'"'^' thick-walled. Thus the summer wood in each year's growth is heavier, stronger, and darker in color than the spring wood. In the wood of many broad leaf trees, such as oak and chestnut, tlie spring wood is also mai'ked by a band of open tubes of larger size called ducts. In othei's, such as maple and beech, these ducts are scattered through the whole season's growth, and in all conifers, as for example the pines and cedars, they are entirely wanting. But the diti'erences in liard- ness and color between the growth of spring and summer are still present. It is sometimes possible to see the line which sepai'ates the growth of two seasons in the bark, as in the case of connnon cork, which is the outer bark of the Cork Oak, a native of southern Europe. If the trunk or branch of an oak tree is cut smoothly aci'o.ss, thin whitish lines may be seen running fi'om within outward (Hg. 10, ))lock at the right). Some of the.se lines begin in the center of the tree and others in each one of the annual rings. These are the medul- lary ra_vs, which make the silver grain in i|uartered oak and other woods. They exist in all kinds of trees, but in many — as, for example, in the Chestnut and in most coni- fers — they are so fine as hardly to be seen with the naked ej'e. Seasoning cracks which run across the rings of growth always follow the lines of these rays, while others most often follow along some annual ring. ^r r rU Fig. 'J.— Wuod of a si.riKi'. greatly niagniHed. 13 ANNTJAL RINGS. It i.s correct to .speak of the.sc rings of gi-o\vth as '"annual rings," for as long as the tree i.s growing healthily a ring is formed each year (Kgs. 1(), 11). It i.s true that two false rings may appear in one year, hut lhe\' are generally so much thinner than the rings on each side that it is not hard to detect them. Very often they do not extend entirely around the tree, as u true ring always does if the tree is sound. Whenever the growth of the tree is interrupted and begins again during the same sea.son, such a false ring is formed. This happens when the foliage is destroyed hy caterpillars and grows again in the same season, or when a very severe drought in early sum- mer stop.s growth for a time, after late frosts, and in similar ca.ses. HEABTWOOD AND SAPWOOD. An annual layer once formed does not change in size or place during the healthy life of the tree, except that it is covered in time by other, younger layers. A nail driven into a tree 6 feet from the ground will .still be at the same height after it is buried under 20 or 60 or JOG layers of atuuial growth. But in most trees, like the oaks and pines, the wood becomes darker in color and harder after it has been in the Fk!. 11.— Aimuiil rings. 14 ti'ee for some j'ears. The openings of its cells become choked so that the sap can no longer run through them. From living sapwood, in which growth is going on, it becomes hcartwood, which is dead, because it has nothing to do with growth (fig. 12). It is simply a strong framework which helps to support the living parts of the tree. This is why hollow trees may flourish and bear fruit. When the tree is cut down, the sapwotxl rots more easil}' than the heartwood, because it takes up water readily and con- tains plant food, which dccaj's very fast. Not all trees have heartwood, and in many the difference in color between it and tlie sapwood is very sliglit. Since water from the roots rises only in the sapwood, it is eas\' to Icill trees with heartwood by girdling them, provided all tiie sap- wood is cut through. But in tho.se which have no heartwood the tuhes (if the older layers of wood can still (Dnvey water to the crown, and when such trees are girdled it is often several years before they die. A great many theoi'ies have been proposed to account for the rise of water into the tops of tall trees, s )me of which, as in the big trees of California, may be over 300 feet from the ground. But none of these theories is quite satisfactory, and it must ))e admitted that we do not yet know how the trees supply their lofty crowns with the water which keeps them alive. TREES IN THE FOREST. The nature of a tree, as shown by \,'„i its behavior in the forest, is called 1 niter jj^ silvicultural character. It is made up of all those qualities upon which the species as a whole, and ever^y individual tree, depend in their struggle for existence. The regions in which a tree will live, and the places where it will flourish best; the trees it will grow with, and those which it kills or is killed by; its abundance or scarcity; its size and rate of growth — all these things are decided l)y the inborn (jualities, or silvicultural character, of each particular kind of tree. the white sap« bark. Milfonl. !') 15 THE VARIOUS BEaXJIREMENTS OP TREES. Dirt'ereiit sjx'cirs of trees, like ditl'eieiit. races of men, have special re(|iiireiiieiits for the things upon which their life depends. Some races, like the Eskimos, live only in cold regions. Others, like the South Sea Islanders, must have a very warm climate to be comforta- ble, and are short-lived in any other (tig. 13). So it is with trees, except that their difl'erent needs are even more varied and distinct. Some of them, like the willows, birches, and spruces of northern Can- ada, stand on the boundary of tree growth within the Arctic^ Circle. Other species grow only in tropical lands, and can not ri'sist even the lightest frost. It is alwaj^s the highest and lowest temperature, rather than the average, which decides where a tree will or will not grow. Thus the average temperature of an island where it never freezes may be onlj^ 60'^, while another place, with an average of 70°, may have occasional frosts. Trees which could not live at all in the latter on account of the frost might flourish in the lower average warmth of the former. In this way »the influence of heat and cold on trees has a great deal to do with their distribution over the surface of the whole earth. Their distril)ution within shorter distances also often depends largely upon it. In the United States, for example, the Live Oak does not 16 grow in Maine nor the Canoe Birch in Florida. Even the opposite sides of the same hill inaj' be covered with two difl'erent species, because one of them resists the late and early frosts and the fierce middaj' heat of summer, while the other requii'es the coolness and moisture of the northern slope (fig. 14). On the eastern slopes, where the sun strikes early in the day, frosts in the spring and fall arc far more apt to kill the young trees or the blossoms and twigs of older ones th;in on those which face to the west and north, where growth begins later in the spring, and where rapid thawing, which does more harm than the freezing itself, is less likely to take place. REaUIIXEMENTS OF TREES FOR HEAT AND MOISTURE. Heat and moisture a<'t together upon trees in such a way that it i.s sometimes hard to distinguish their effects. A diy country or a dr}' slope is apt to l)e hot as well, while a cool northern slope is almost always moister than one turned toward the south. Still the results of 17 the demand of trees for water-ciui usually l)c distinguished from the results of their need of warmth, and it is found that moisture has almost as great an influence on the distribution of trees over the earth us heat itself. Indeed, within any given region it is apt to be much more conspicuous, and the smaller the region the more noticeable often is its effect, because the contrast is more striking. Thus it is fre- quently easy to see the difference between the trees in a swamp and those on a dry hillside nearl)v, when it would be far less easy to dis- tinguish the general character of the forest which includes both swamp and hillside from that of another forest at a distance. In many instances the demand for water controls distribution altogether. For this reason the forests on the opposite sides of mountain ranges are often composed of entirely different trees. On the west slope of the Sierra Nevada of California, for example, where there is plenty of moisture, there is also one of the most beautiful of all forests. The east slope, on the contrary, has compavativeh' few trees, Ijecause its rainfall is very slight, and those which do grow there are small and stunted in comparison with the giants on the west. Again, certain trees, like the Bald Cypress and the River_ Birch, are commonly found only in ver\' moist land; others, like the mescpiites and the Pinyon or Nut Pine, only on the driest soils; while still others, like the Red Cedar and the Red Fir, seem to adapt themselves to almost any degree of moisture, and are found on both very wet and verj^ dry soils. In this way the different demands for moisture often separate the kinds of trees which gi'ow in the bottom of a valley from those along its slopes, or even those in the gullies of hillsides from those on the rolling land between. A mound not more than a foot above the level of a swamp is often covered with trees entirely different from those of the wetter lower land about it. Such matters as these have far more to do with the places in which different trees grow than the chemical composition of the soil. But its mechanical nature — that is. whether it is stiff or loose, fine or coarse in grain, deep or shallow — is very important, because it is dii'ectly connected with heat and moisture and the life of the roots in the soil. REQUIREMENTS OF TREES FOR LIGHT. The relations of trees to heat and moisture are thus largely respon- .sible for their distribution upon the great divisions of the earth's surface, such as continents and mountain ranges, as well as over the smaller rises and depressions of every region where trees grow. But •while heat and moisture decide where the different kinds of trees can grow, their influence has comparatively little to do with the struggles of individuals or species against each othev for the actual possession 26900— No. 173—03 2 18 of the gTouncl. The outcome of thesse struggles depends less on heat and moisture than on the possession of certain ijualities, among which is the ability to bear shade. With regard to this power trees are roughly divided into two classes, often called shade-bearing and light- demanding, following the German, but better named tolerant and intolerant of shade. Tolerant trees are those which flourish under more or less heavy shade in earlj^ youth; intolerant trees are those which demand a comparatively slight cover, or even imrestricted light. Later in life all trees require much more light than at first, and usually those of both classes can live to old age only when they are altogether unshaded from above. But there is always this difference between them: The leaves of tolerant trees will bear more shade. Consequently the leaves on the lower and inner parts of the crown arc more vigorous, plentiful, and persistent than is the case with intolerant trees. Thus the crown of a tolerant tree in the forest is usually denser and longer than that of one which bears less shade. It is usually true that the seedlings of trees with dense crowns are able to floui'ish under cover, while those of light-crowned trees are intolerant. This rough general rule is often of use in the study of forests in a new country, or of trees whose silvicultural character is not known. TOLERANCE AND INTOLERANCE. The tolerance or intolerance of trees is one of their most important silvicultural characters. Frequently it is the first thing a forester seeks to learn about them, because what he can safely luidertake in the woods depends so largely upon it. Thus tolerant trees will often grow vigorously under the shade of light-ci'owned trees (fig. 15) above them, while if the positions were reversed the latter would speedily die. The proportion of ditt'erent kinds of trees in a forest often depends on their tolerance. Thus hemlock sometimes replaces White Pine in Pennsylvania, because it can grow beneath the pine, and so be ready to fill the opening whenever a pine dies. But the pine can not grow under the hemlock, and can only take possession of the ground when a fire or a windfall makes an opening where it can have plenty of light. Home trees after being overshaded can never recover their vigor when at last they are set free. Others do recover and grow vigorously even after manj' years of starving under heavy shade. The Red Spruce in the Adirondacks has a wonderful power of this kind, and makes a line tree after spending the first fifty or even one hundred years of its life m reaching a diameter of two inches. The relation of a tree to light changes not onl}? with its age, but also with the place where it is growing, and with its health. An intolerant tree will stand more cover where the light is intense than in a cloud3' northern region, and more if H has plenty of water than J73 19 with ii scauty .supply- Vigorous seedlings will get along with less light than sickly ones. Seedlings of the same species will prosper under heavier shade if they have always grown under cover than if they have had plenty of light at first and have been deprived of it after^^ard.--. Ea tern N ith Car lina THE RATE OF GROWTH. The rate of growtli of different trees often decides which one will survive in the forest. For example, if two intolerant kinds of trees should start together on a burned area or an old field, that one which grows faster in height will overtop the other and destroy it in the end by cutting oif the light. Some trees, like the Black Walnut, grow rapidU- from their earliest youth. Others grow very slowly for the first few 3'ears. The stem of the Longleaf Pine, at 4 years old, is usuallj" not more than 5 inches in length. During this time the roots have been growing instead of the stem. The period of its rapid growth in height comes later. The place where a tree stands has a great influence on its rate of growth. Thus the trees on a hillside are often much smaller than those of equal age in the rich hollow below, and those on the upper 20 slopes of a high iiiountiiin arc ((minioiily starved and stunted in com- parison with the vigorous forest lower down. The Western Chinqua- pin, which reaches a height of 150 feet in the coast valleys of nortTiern California, is a mere shrut) at high elevations in the Sierra Nevada. The same thing is often observed in passing from the more temperate regions to the far north. Thus the Canoe Birch, at its northern limit, rises only a few inches above the ground, while farther south it becomes a tree sometimes 120 feet in height. THE REPRODUCTIVE POWER OF TREES. Another matter which is of tin the rcprodu<-tivc power of his trees fleopest interest to the forester is H;xce])t in the case of sprouts and other growth fed by old roots, this depends first of all on the quantity of the seed which each tree bears; ])ut so many other considerations afi'cct the result that a tree which bears seed al)undantly may not re- produce itself very wel i . A part of the seed is always unsound, and sometimes nuich the larger part, as in tlie case of the Tulip Tree. Hut even a great abun- danceof sound seed does not always insure good reproduction. Theseeds may not find the right surroundings for successful germination, or the infant trees may pi'rish for want of water, light, or suitable soil. Where there is a thick layer of dry leaves or needles on the ground, seedlings often perish in great numbers because their delicate rootlets can not reach the fertile soil beneath. The same thing happens when there is no hunnis at all and the surface is hard and dry. The weight of the seed also has a power- ful influence on the character of reproduction. Trees with iieavy seeds, like oaks, hickories, and chestnuts, can sow them only in their own neighborhood, except when they stand on steep hillsides or on the banks of streams, or when birds and squirrels carry the nuts and acorns to a distance. Trees with light, winged seeds (tig. 16), likethe poplars, birches, and pines, have a great advantage over the others, 21 l)eoause they can drop their seeds a long way oflf. The wuid is the means by whicrh this is l)ronght al)out, and the adaptation of the seeds themselves is often very curious and interesting. The wing of a pine seed, for example, is so placed that the seed whirls when it falls, in such a way that it falls very slowly. Thus the wind has time to carry it away before it can reach the ground. In heavy winds pine and other winged seeds are blown long distances — sometimes as much as several miles. This explains how' certain kinds of trees, like the (iray Birch and the White Pine, grow up in the middle of open pastures, and how others, such as the Lodgepole Pine, cover great areas, far from the parent trees, with young growth of even age. Such facts help to explain why, in certain places, it happens that when pines are cut down oaks succeed them, or when oaks are removed pines occupy the ground. It is very often true that young trees of one kind are already growing unnoticed beneath old trees of another, and so are ready to replace them whenever the old trees are cut away. PURE AND MIXED FOREST. The nature of the seed has much to do with the ilistri))utioii of trees in pure or mixed forest. Some kinds of trees usually grow in bodies of some extent containing only a single kind; in other words, in pure forest. The Longleaf Pine of the South Atlantic and Gulf States is of this kind, and so is the Lodgepole Pine of the West. Conifers are more apt to grow in pure forest than broadieaf trees, because it is more common for them to have winged seeds. The gi'eater part of the heavy-seeded trees in the United States are deciduous, and most of the deciduous trees grow in mixed forest, although there are some conspicuous exceptions. But even in mixed forests small groups of trees with heavy seeds are common, because the young trees naturally start up beneath and around the old ones. A 'heavy seed, dropping from the top of a tall tree, often strikes the lower branches in its fall and bounds far outside the circle of the crown. Trees which are found only, or most often, in pure forest are the social or gregarious kinds; those which grow in mixture with other trees are called scattered kinds. Most of the hardwood forests in the United States are mixed; and many mixed forests, like that in the Adirondacks, contain l)oth broadieaf trees and conifers. The line between grega- rious and scattered species is not always well marked, because it often happens that a ti'ee may be gregarious in one place and live with many others elsewhere. The Western Yellow Pine, which forms, on the plateau of central Arizona, perhaps the largest pure pine forest of the earth, is frequently found growing with othei' species in the mountains, especially in the Sierra Nevada of central California. 22 Trees ■which occupy the yrouiid to the exclusion of all others do so l>ecaus(> th(M- succeed hcttcr. under the cone some other reason why they are bet- ter titted for theii' surroundings. But the gregarious trees are not all alike in their ability to sustain themselves in different situations, while the differences between some of the mixed-forest species are very marked indeed. Thus, Black Walnut, as a rule, grows only in rich, moist soil and Beech only in damp situations. Fire Cherry, on the other hand, is most common on lands which have been devas- tated l\y tire, and the Rock Oak is most often found on dry, barren ridges. The Tupelo or Black Gum and the Red ^Nlaple both grow best in swamps, })ut it is a conmion thing to find them also on dry, stony soils at a distance from water. The knowledge of such ([ualities as these is of great importance in the management of forest lands. REPRODUCTION BY SPROUTS. Besides reproduction from seed, which plays so large a part in the struggle for the ground, reproduction })y sprouts from old roots or stumps (tig. 17) is of great importance in forestry. Trees differ very much in their power of sprouting. In nearh' all conifers except the California coast Redwood, which has this ability beyond almost ever}' other tree, "it is lacking altogether. The Pitch or Jack Pine of the Eastern United States has it also to some extent, but in most places the sprouts usually die in early youth and seldom make mer- chantable ti'ees. In the broadleaf kinds, on the other hand, it is a general and very valuable quality. Young stumps, as a rule, are much more productive than old ones, although some prolific species, like the Chestnut, sprout plentifully in old age. Other species, like the Beech, furnish numerous sprouts from young stumps and very few or none at all from old ones, and still others never sprout freely even in early youth. THE LIFE OF A FOREST. The history of the life of a forest is a story of the help and harm which the trees receive from one another. On one side every tree is engaged in a relentless struggle against its neighbors for light, water, and food, the three things trees need most. On the other side, each tree is constantly working with all its neighbors, even those which stand at some distance, to bring about the best condition of the soil and air for the growtli and fighting power of every other tree. A COMMUNITY OF TREES. The life of a community of trees is an exceedingly interesting one. A forest tree is in manj' ways as nuich dependent upon its neighbors for .safety and food as are the inhabitants of a town upon one another. The difference is that in a town each citizen has a special calling or occupation in which he works for the service of the commonwealth, while in tiie forest everv tree contriliutes to the general welfare in 24 nearh' all the ways in which it is benefited by the conimunit}-. A for- est tree helps to protect its neighlioi-s against the wind, which might overthi'Gw them, and the sun, which is ready to dry up the soil about their roots or to make sun cracks in their bark by shining too hotly upon it (tig. 18). It enriches the earth in which they stand b^- the fall of its leaves and twigs, and aids in keeping the air about their crowns, and the soil about~their roots, cooler in summer and warmer in winter than it would he if each tree stood alone. With the others it forms a Fig. is.— Forest trees stanrtiHK h common canopy under which the seedlings of al! the members of this protective union are sheltered in early j'outh, and through which the beneficent influence of the forest is pi-eservedand extended far beyond the spread of the trees themselves. But while this fruitful coopera- tion exists, there is also present, just as in a village or a city , a vigorous strife for the good things of life. For a tree the l)est of these, and often the hardest to get. are water for the roots and space and light for the crown. In all l)uf very di-y places there is water enough for 25 all the trees, and often more than enough, as for example in the Adirondack forest. The struggle for space and light is thus more important than the struggle for water, and as it takes place above ground it is also much more easily observed and studied. Light and space are of such impoi'tance because, as we have seen, the leaves can not assimilate or digest food except in the presence of light and air. The rate at which a tree can grow and make new wood is decided chiefly by its ability to assimilate and digest plant food. This power depends upon the number, size, and health of the leaves, and these in turn u]ion th(> amount of space and light which the tree can secui'e. THE LIFE OF A FOREST CROP. thi'ii l:irg('ly an account of »ini. Mini. altlioiii'-li the \"erv The story of the life of a roicst croi) the competition of the trees for liglit an strength which enables them to carry on the fight is a result of their association, still the deadly struggle, . in which the victims arc many times more in number than those which survive, is apt alone to absorb the at- tention. Yetthe mutual help of the trees to each other is always going quieth'on. Every tree continually comforts and assists the other trees, which are its friendly enemies. The purpose here is to follow the progress of a forest crop of uni- form age from the seed through all the succes- sive phases of its life until it reaches matu- rity, bears seed in its turn, and finallv de- ,. . . ,.,.." , Fl... I'J.— A Wllilu Pillr sc.-.llilii;, sllmvi].!,Mll..yk■Il.U■rr.l()t^. cbnes m tertility and strength until at last it passes away and its place is tilled by a new generation. The life history which we ai-e about to follow , as it unfolds itself through the course of several hundred yeai's, is full of struggle 26 and danger in youth, restful and dig-nitied in age. The changes which pass over it are vast and full of the deepest interest, hut they are very gradual. From beginning to end one stage melts insensibly into the next. Still, in order to study and describe them (H)nveniently, each stage must have limits and a name. THE SEVEN AGES OF A TREE. Avery practical way of classifying trees according to size is the fol- lowing: Young trees which have not yet reached a height of 3 feet are sesdlliK/x (tig. 19). They are called .seedlings in spite of the fact that any tree, of whatever age, if it grew from a seed, is properly called a .seedling tree. Trees from 3 to 10 feet in height are huuiU fniplinyx, and from 10 feet in height until they reach a diameter of i inches they are hiiyi' saplings. Small p< ilex are from 4- to 8 inches in diameter, and Imyt^ j>olfS from Sto 12 inches in diameter. Trees from 1 to 2 feet through are standards, and, hnally, all trees over 2 feet in diameter are veterans. It is very important to remember that all these diameters are meas- ured at the height of a man's chest, about 4 feet 6 inches from the ground. In forestry this is, roughly speaking, the general custom. HOW THE CROP BEGINS. Let us imagine an abundant crop of tree seeds lying on the ground in the forest. How they came there does not intere.st us at present; we do not care to know whether they were carried by the wind, as often happens with the winged seeds of manj' trees, such as pines and maples, whether the squirrels and birds dropped and planted some of them, as they frequently do acorns and chestnuts, or whether the old trees stood closely about and sowed the .seeds themselves. We will suppose them to be all of one kind, and to be scattered in a place where the soil, the moisture, and the light are all just as thcT should 1)6 for their successful germination, and afterwards for the later stages of their lives. Even under the best conditions a con.siderable part of the fallen .seed may never germinate, but in this case we will assume that half of it succeeds. As each seed of our forest germinates and pushes its tirst slendei- rootlet downward into the earth, it has a very uncertain hold on lite. Even for some time afterwards the danger from frost, drynes.s, and excessive moisture is very serious indeed, and there are many other foes by which the young .seedlings may be overcome. It sometimes happens that great numbers of them peri.sh in their earliest youth becau.se their roots can not reach the soil through the thick, dry coating of dead leaves which covers it. But our young trees pass through the beginning of these dangers with comparatively little loss, and a plenti- ful crop of seedlings occupies the ground. As yet, however, each little treo stands free from those about it. As j'et, too, the life of the \()iiny foivst iiuiy he threatened or i'\eii destroyed by any one of the enemies already mentioned, or it may suffer just as severely if the cover of the older trees above it is too dense. In the beginning of their lives seedlings often i-equire to ])e protected In' the shade of their elders, but if this protection is too long continued they sutler for want of liglit, and are either killed outright or live only to drag on stunted and unliealthy lives. THE FOREST COVER ESTABLISHED. The (Top which we are following has had a suitable proportion of shad(( and light during its earliest years, and the seedlings have spread until their crowns begin to meet. Hitherto each little tree has had all the space in the ail' and soil that it need(>d for the expansion of its top Fk:. 20.— Youug White Pine seedlings whu»e li>wer braiiehes have just begun to iuterfere. and roots. This would have been entirely good, except that meanwhile the soil about the trees has been more or less exposed to the sun and wind, and so has become dryer and less fertile than if it had been under cover, and consequently the growth has been slow. Hut now that the crowns are meeting, the situation becomes wonderfully changed. The soil ])egins to improve rapidly, because it is ])rotected by the cover of the meeting crowns (tig. 2(») and enriched by tlie leaves and twigs which fall from them. THE BEGINNING OF THE STRUGGLE. In .so far the conditions of life are better, and in consec{uence the growth, and more especially the height growth, begins to show a marked increase. On the other hantl, till the new strength is in 28 immediate demand. With the added vigor which the trees are now helping eacli other to attain, comes the most urgent need for rapid development for the decisive struggle at hand. The roots of the j^oung trees contend with each other in the .soil for moi.sture and the plant food which it contains, while in the air the crowns struggle for space and light. The latter is by far the more important battle. The victors in it overcome by greater rapidity of growth at the ends of the branches, for it is by growth there, and there only, that trees increase in height and spread of crown. Growth in this way was going on unchecked among the young trees before the crowns met, but now onlj^ the upward-growing branches can develop freely. The leaves at the ends of the side branches have now less room and, a))ove all, less light, for they are crowded and thrust aside by those of the other trees. Very often they ai'e l)ruised l)y thrashing against their neigh))ors when the wind blows, or even broken ofl' while still in the bud. Leaves exposed to such dangers are unhealthy. They transpire less than the healthy un(listui-l)ed leaves of the upper part of the crown, and more and more of the undigested food from the roots goes to the stronger leaves at the top as the assimilating power of the side leaves dwindles with the loss of light. The young branches share the fortunes of their leaves and are vigorous or sickly according to the condition of the latter. For this reason the growth of the tops increases, while that of tiie lower lateral branches, as the tops cover them with a deeper and deeper shade, becomes less and less, (iradtially it cea.ses altogether, and the branches perisli. This jirocess is called natural pruning, and from the time when it l)egiiis tlie existence of the young forest, unless it should l)e oveitakeii l>y (iic or sonic other great calainity. is practically secure. GROWTH IN HEIGHT. At this time, as we have seen, tlie crowns of all the young trees are growing faster at the tops than at the sides, for there is unlimited room a})0ve. But some are growing faster than others, (hither liecause their roots are more developed or in better soil than those of tlie trees about them, because they have been freer from the attacks of insects and other enemies, or for some similar reasons. Some trees have an inborn tendency to grow faster than others of the same species in the same surroundings, just as one .son in a familj' is often taller than the brothers with whom he was lirought up. Rapid growth in height, from whatever cause it proceeds, lirings not only additional light and air to the tree which excels in it, but also the chance to spread laterally, and so to complete the defeat of its slower rivals l>y ovei'topping liiein. 29 THE STRUGGLE CONTINUED. Those tr('(\s wliicli luivc giiiued thi.s iidviintiigc over tlieir neighl)ors are called dominant trees, while the surviving laggai'ds in the race are said to he overtopped when the}' are hopelessly l)ehind, and retarded when less badlj' beaten. Enormous numbers of seedlings and small saplings are suppressed and killed during the early youth of the forest. In the v'oung crop which we are following man}' thousands perish upon every acre. Even the dominant trees, which are tem- porarily free when they rise above their neighbors, speedily come into conflict with each other as they spread, and in the end the greater portion is overcome. It is a very deadly struggle, but 3'ear by 3'ear the difl'erences between the trees become less marked. Each separate individual clings to life with greater tenacity, the strife is more pro- tracted and severe, and the number of trees which pei'ish grows liipidly smaller. But so great is the pressure when dense groups of young trees are evenly matched in size and rate of growth that it is not very unusual to tind the progress of the young forest in its early stages almost stopped and the trees uniformly sickly and under- sized, on account o,f the crowding. The forest we have been following has now passed thi-ough the small-sapling stage, and is composed chiefly, but not exclusively, of large saplings. Among the overtopped and retarded trees, which often remain iu size classes which the dominant trees have long since outgrown, there are still many low saplings. Even between the dominant trees, in a healthy forest, there are alwaj'S great differences. Increase in height is now going on ra])idly among these high sap- lings, and either in this stage or the next a point is reached when the topmost branches make their longest yearly growth, which is one way of saying that the trees make their most rapid height growth as large saplings or smali poles. Later on, as we shall see, these upper branches lengthen much more slowly, until, in standards and veterans, the growth in height is small, and in \cry old trees finally ceases altogether. NATURAL PRUNING. While the trees ari' pushing u[) most rapidly, the side l)ranches are "most quickl}' overshaded, and the process of natural pruning goes on with the greatest vigor. Natural jiruning Is the reason why old trees in a dense forest have only a small crown high in the air, and why their tall, straight trunks are clear of branches to such a height above the ground. The trunks of trees grown in the open, where even the lower limbs have abundance of light, are branched either quite to the ground or to within a short distance of it (fig. 21). But in the forest not only are the lower side branches continually dying for want of light, but the tree rids itself of them after they are dead and so frees 30 its trunk from them entirely. When a branch dies the annual layer of new wood is no longer deposited upon it. Consequently the dead Fi«. 21.— ImiJtrlcct imtuful i branch, where it is inserted in the tree, makes a little hole in the first coat of living tissue formed o\'er the live wood after its death. The 31 edg'ct* of tliis hole make a soi"t of ctjllar about the base of the dead branch, and as a new layer is added eaeh year they press it more and more tif^htly. So strong does this compression of the living wood become that at last what remains of the dead tissue has so little sti'ength that the branch is broken ofl' by a storm or even "falls of its own weight. Then in a short time, if all goes well, the hole closes, and after a while little or no exterior trace of it I'eniains. Knots, such as those which are found in boards, are the marks left in the trunk by l)ranchc.s which have disappeared. THE CULMINATION OF GBOWTH. While the young trees are making clean trunks bo rapidly during the period of greatest yearh* height growth they are also making their greatest annual gains in diameter, for these two forms of growth gen- erally culminate about the same time. A little later, if there is an\' difference, the young forest's highest yearly rate of growth in volume is also reached. For a time these three kinds of growth keep on at the same rate as in the past, but afterwards all three begin to decrease. Growth in diameter, and in volume also, if the trees are sound, goes on until extreme old age, but height growth sinks very low while the two others are still strong. For many years before this happens the struggle between the trees has not been so deadly, because they have been almost without the means of overtopping one another. When the end of the period of principal height growth is reached the trees are interfering with each other very little, and the struggle for life begins again in a different way. As the principal height growth ceases, and the tops no longer shoot up rapidly above the side branches, the crowns lose their pointed shape and become compara- tively flat. The chief reason why trees stop growing in height is that they are not able to keep the upper parts of their crowns properly supplied with water above a certain distance from the ground. This distance varies in different kinds of trees, and with the health and vigor of the tree in each species, but there is a limit in every case above which the water does not reach. The power of the pumping machinery, more than any other quality, determines the height of the tree. THE END OF THE STRUGGLE. Now that the tree can no longer expand at the top, it must either suffer a great loss in the number of its leaves or be able to spread at the sides: for it is clear that not nearly so many leaves can be exposed to the light in the flattened crown as in the pointed one. just as a pointed roof has more surface than a flat one (fig. 22). It is just at this time, too, that the trees begin to bear .seed most abundantly, and it is of the greatest importance to each tree that its digestive appa- 32 ratus in the leaves should bo able to furnish a large supply of digested food. Consequeiitlj tlie struggle for space is fiercely renewed, only now the trees no longer attempt to overtop one another, having lost the power, but to crowd one another awaj' at the sides. The whole forest might sufler severely at this point from a deadlock such as sometimes happens in early youth were it not for the fact that the trees, as they grow older, become more and more sensitive to any shade. Many species which stand crowding fairly well in 3'outh can not thrive in age unless their crowns are completely free on every side. Each of the victors in this last phase of the struggle is the sur- vivor of hundreds (or sometimes even of thousands) of seedlings. Among verj' numerous competitors they have shown themselves to be the best adapted to their surroundings. Natural selection has niade it clear that these are the best trees for the place. These are also the trees which bear the seed whence the younger generations spring. Their offspring will inherit their fitness to a greater or less degree, and iti their turn will be subjected to the .same rig(M-ous test, by which only the best are allowed to roach matui'it}'. Under this sifting out of the weak and the unfit, our native trees have been prejiarod through thousands of generations to moot the conditions under which they must live. This is why they are so much more apt to succeed than species from abroad, which have not been fitted for our climate and soil by natural selection. The forest which we .saw first in the .seed has now pa.ssed through all the more vigorous and active stages of its life. The trees have become standards and veterans, and large enough to 1)0 valuable for lumber. Kaj)id growth in height has long been at an end, diameter growth is slow, and the forest as a whoh; js increasing very little in volume as time goes on. The trees are I'ijic fni- tiie harvest. Out of the many things wliic li MiJLiht happen to our malure forest, wo will onlv consider three. Fig. 22.— DiuKiiuu to show win- a stmrply coiiioal crown receives more light than a flat one. DEATH FROM WEAKNESS AND DECAY. In the first place, we will suj)])ose that itstands untouciieil until, like the trees of the virgin forest, it meets its death from weakness and decay. The trees of the mature primeval forest live on, if no accidents intervene, almost at peace among themselves. At length all conflict between them ends. The whole power of each tree is strained in a new struggle against death, until at last it fails. One by one the old trees disappear. But long before they go the fQi'erunners of a new 33 genpration have sprung up wherevei* light camo in between their isolated crowns. As the old trees fall, with intei'vals often of inan}^ years between their deaths, young growth of various ages rises to take their place (fig. 2?)), and when the last of th(>. old forest crop has vanished there may be differences of a hundi-ed }-(>ars among the young trees which succeed it. An even-aged crop of considerable extent, such as wc have been consideinng, is not usual in the virgin forest, where trees of \ery different ages grow side bj' side, and when it does occur the next generation is far less uniform. The forest whose history has just been sketched was chosen, not because it represents the most common type of natural forest, but because it ilkistrates better than any other the progress of forest growth. The wood of a tree which dies in the forest is almost wholly wasted. For a tmie the rotting ti-unk may serve to retain moisture, but there is little use for the carbon, oxygen, and hydrogen which make up its greater part. The mineral constituents alone form a useful fertilizer, but most often there is already an abundance of similar material in the soil. Not only is the old tree lost, but evei- since its maturity it has done little more than intercept, to no good purpose, the light which would otherwise have given vitality to a valuable crop of younger trees. It is only when the ripe wood is harvested properly and in time that the forest attains its highest usefulness. 2G900— No. 173—03 3 173 31 DESTRUCTIVE LUMBERING. A ficcond thing wliich may happen to a forest is to be cut down without care for the future (iig'. 2J:). The yield of a forest lumbered in the usual way is more or less thoroughly harvested, it is true, ))ut at an enormous cost to the forest. Ordinary lumbering injures or destroys the 3'oung growth. ))oth in the ]irpsent and for the future, provokes and feeds fires, and does harm of many other kinds. In many cases i-i(j. .1.— lK->lniLlnL' llDlll -t I,m1u,,,„1 Ijrlt, Uumbol(it Count;, LaL its result is to aniiiiiilatc the productive capacity of forest land for tens or scores of years to couk*. CONSERVATIVE LUMBERING. Correct methods of forestry', on the other hand, maintain and increase l)otIi the productiveness and the capital value of forest land; harvest the yield far more comj^letely than ordinary lumbering, although less rapidly; prepare for, encourage, and preserve the young growth; tend to keep out fires; and in general draw from the forest, while pro- tecting it, the best return which it is capalile of giving. The application of such methods is the third possibility for the crop just described, and in their application is to be found the wisest, safest, and most satisfactory way of dealing with the forest. Then- iiiT still iiiiiny ))liiccs in tlic I'nitprl States, however, where transportiitioii is so costl}- that, as yet, forestry NA'ill not pay from a business point of view . ENEMIES OF THE FOREST. The fofesi is threatened by iii;my ciiciiiics, ol' wiiich Hiv and reck- li'ss lumbering are th(>- worst. Tn the United States sheep grazing and w ind eom(> next, (battle and horses do much less damage than sheep, and snow break is less costly than windfall. 1 landslides, floods, insects, and fungi are sometimes very harmful. 1 ii certain situations numbers of trees are killed by lightning, which has also been known to set the woods on fire, and the forest is attacked in man}' other waj's. For example. l)irds and s(|uirrels often prevent young growth by devour- ing great ([uantities of nuts and other seeds, while porcupines and mice fr(M|U('ntly kill young trees by gnawing away thcii' bark. MAN AND NATURE IN THE FOREST. Most of thes(> I'oes may be called natural enemie>, for they would injure the forest tc,) a greater i>i' less (>xtent if the action of man were altogether removed. Wild animals would take the place of domestic sheep and cattle to some degree, and fire, wind, and insects would still attack the forest. But many of the most serious dangers to the forest are of human origin. Such are destructive lumbering (tig. 2-4) and excessive taxation on forest lands, to which nuich bad lumbering is directly due. So high are these taxes, for in many cases they amount to 5 or even asonal)le taxation of timber land, have been flourishing and rich. GRAZING IN THE FOREST. Whether o-razing animals are comparatively' harmless to the forest or among its most dangerous enemies depends on the age and charac- ter of the woods as well as upon the kind of animals that graze. A voung forest is always more exposed lo such injury than an old one, and steep slopes are more subject to damage than more level o-round. Whether the young trees are conifers, and so more likely 36 to suffer fi'oni tranipling- than from being eaten, or broadleaf trees, and so n>ore likely to be devoured, they should be jjrotected from pasturing animals until they arc large enough to be out of danger. GRAZING AND FIBE. Grazing in the forest does harm in three ways. First, it is a fertile cause of forest fires. Burning the soil cover of grass and othci' plants improves the grazing, either permanently, by destroying the forest and so extending the area of pasturage, or temporarily, })y Fig. 25. — Baud of sheep in a forest reserve. Cascade Mountains, Wa 5,«00 feet. County, Greg. Altitude, improving the quality of the feed. For one or the other of these objects, but chiefl}^ for the latter, vast areas are annually burned over in nearly every part of the United States where trees grow. The great majority of these fires do not kill the old trees, but the harm they do the forest and, eventually, the forage plants themselves, is very serious indeed. The sheepmen of the West are commonly accused of setting many forest fires to improve thi> grazing, and they are also vigorously defended from this charge. Rut the fact remains that large areas where sheep now graze would be covered with forests except for the action of more or less I'ccent fires. 37 TRAMPLrHG. Trampling is the second way in which grazing animals injure the forest. Cattle and' horses do comparatively little harm, although their hoofs compact the soil and often tear loose the slender rootlets of small trees. Sheep, on the contrary, are exceedingly harmful dig. 25), especiall}' on steep slopes and where the soil is loose. In such places their small, sharp hoofs cut and powder the soil, break and overthrow the young trees, and often destroy promising young foi'ests altogether. In many places the effect of the trampling is to destroy the forest floor and to interfere very seriously with the flow of streams. In the Alps of southern France sheep grazing led to the destruction, rirst, of the mountain forests, and then of the grass which had replaced them, and thus left the soil fully exposed to the rain. Great floods followed, beds of barren stones were spread over the fertile fields by the force of the water, and many rich valleys were almost or altogether depopulated. Besides the loss occasioned in this way, it has cost the French people tens of millions of dollars to repair the damage begun by the sheep, and the task is not yet finished. The loss to the nation is enormously greater than any gain from the moun- tain pastures could have been, and even the sheep owners themselves, for whose profit the damage was done, were losers in the end, for their industry in that region was utterly destroyed. BROWSING. Th(> third way in wliicli grazing animals injure the forest is by feed- ing on the young trees. In the western part of the ITnited States, where most of the forests sire evergreen, this is far less important than the damage from either tire or trampling, for sheep and other animals seldom eat young conifers if they can get other food. Even where broadleaf trees prevail browsing rarely leads to the destruction of any forest, although it commonl}- results in scanty young growth, often maimed and luisound as well. Goats are espe- cially harmful, and where tlicy abound the healthy reproduction of broadleaf trees is practically impossible. In the United States they are fortunately not common. Cattle devour tender young shoots and branches in vast quantities, often living for months on little else, and sheep are destructive in the same wa}'. Hogs also find a living in the forest, but they are less harmful, because a large part of their food consists of seeds and nuts. East of the Great Plains very large numbers of cattle and hogs are turned into the woods, but sheep grazing in the forest is most widel^v developed in the West, and espe- cially iu California, where it should be prevented altogether, in Ore- gon and Washington, where it should be regulated and restricted, and in some interior regions, like Wyoming and Mew Mexico, when; it 88 should be rigidly' excluded from all sleep inountnin reo-ions, and eare- I'ulh^ regulated on niui'e level ground. FOREST INSECTS. Insects are constantly injuring the forest, just as year by year they bring loss to the farm. Occasionally their ravages attain enormous proportions. Thus a worm, which afterwai'ds develops into a sawflv, has since 18S3 killed nearly every full-grown larcli in the Adirondacks l)V eating away the leaves. Even the small and vigorous larches do not escape altogether from these attat'ks. Conifers, such as the larch and spruce, are much more likeh' to sutler from the attacks of insects than broadleaf trees. About the year 187t) small bark beetles began to kill the mature spruce trees in the Adirondacks, and ten years later, when the worst of the attack was past, the forest had been practi- cally deprived of all its largest spruces. This pest is still at work in northern New Hampshire and in iSIaine. FOREST FUNGI. Fungi attack the forest in many ways. Some kill the roots of trees, some grow upward from the ground into the trees and change the sound wood of the trunks to a useless rotten ma.ss, and the minute spores (or seeds) of others float through the air and come in contact with every external part of the tree above ground. Wherever the wood is expo.sed there is danger that spores will find lodgment and breed disea.se. This is a .strong reason why all wounds, such as those made in pruning, should be covei-ed with some substance like j)aint or tar to exidude the air and the sj)oi-es it carries. WIND IN THE FOREST. The effect of wind in the virgin forest is not wholly injurious. Although in many regions it overthrows great immbers of old trees, their removal is usually followed by a vigorous young growth where the old trees stood. In this way the wind helps to keep the forest full of young and healthy trees. But it also breaks and l)lows down great numbers of useful growing members of the forest (tig. 26). Much of this windfall occurs among shallow-rooted trees, or where tlie ground is .soft l»ecause soaked with water, or where the trees have been weakened })y unsoundness or tire. Some storms are strong enough to break the trees they can not overthrow. Damage from wind is not unconnnon in many parts of the United States, and in places the lo.ss from it is very serious. Near the town of High Springs, in Alachua County, Fla., for example, in a region very subject to storms, there is a tract of many square miles, once covered with 3'.) Longleaf Pino, oror which practically all the troos wore killed l>y a great storm several years ago. Some were thrown Hat. some were so racked and so hroken in the top that they died, and very many were diail 111 Uie ulyuiiJii: purest Ucscrvi;, WaaluiigLuu. snapped oti' 15 to 30 feet above the ground. There is little nse in taking precautions against such great calamities, yet the loss from windfall may be very much reduced liy judicious cutting. An unbroken forest is least exposed. 40 SNOW IN THE FOREST. 8now often loads down, l)reaks, and cni.sbo.s tall j-oiui','- trees (tig. 27), especially if wet snow falls heavily before the broadleaf trees have shed their foliaye in tlie fall. Such injury is difficult to guard against. -A young siiruci; luadrd will hut it is well to know tiiat very slim, tall trees suffer more than those whose growth in diameter and height have kept better pace with each other. In many regions snow is so us(>ful in protecting the soil and the young trees that the lianu it docs is (juitc ovcrlialanced by its benefits. 41 FOREST FIRES. Of all the foes which attack the ■\V(^()cl lands of Nortli America no otlici- is so tcrrihle as fire. Forest tires sprinjij from many different causes. They are often kindled along railroads by sparks from the locomotives. Carelessness is responsible for many tires. Settlers and farmers clearing land or Vmrning grass and brush often allow the fii'e t<} escape into the wt^ods. Someone may drop a half-})urned match or tiie glowing tobacco of a pipe or cigar, or a huntei- or prospector may neglect to extinguish his camp tire, or may build it where it will bur- i-iiw into t!ic Ihit'k dulf far beyond his i-eaeh. to sniuliler for days, or s~ll r tt u„ tubs t liiL kllltd \ rii ol I td 1 r iui o ii dt 1 bj joun„ till 1 ut I 1 I r and Western Heml I Olvmi 1 r tl cr\ W ushint,t n weeks, and perhaps to l)reak out as a destructive fire long after he is gone. Many lires are set for malice or revenge, and the forest is often burned over by huckleberry pickers to increa.se the next season's <;rowth of berries, or by the owners of cattle or sheep to make better pasture for their herds. Fire sometimes renews an old forest by killing the veterans and so permitting vigorous young trees to take their place (tig. 'Jo). There is danger from forest tires in the dry portions of the spring and summer, but those w'hich do most harm usuallj- occur in the fall. At whatever time of the year they appear, their destructive power {lepends very nuich on the wind. They can not travel against it except 42 when burning up hill, and not even then if the wind is strong. The wind may give them .strength and .speed 1)y driving them swiftly through unburned, infiummaljle forests, or it may extinguish the iiercest hre in a short time by turning it back over its path, whei-e there is nothing left to burn. Tii lighting forest fire.s the wind is always the first thing to eonsidi-r, and it.s direction must l)e carefully watched. A sudden change of wind maj^ check a lire, or may turn it oflf in a new direction and perhaps threaten the li\es of the men at work by driving it suddenly down upon them. HISTORIC FOREST FIRES. When all the conditions arc favoralile, forest tires sometimes reach gigantic proportions. A few such fires have attained historic impor- tance. One of the.se is the Miramichi fire of 1825. It began its great- est destruction about 1 o'clock in the afternoon of October 7 at a place about 60 niih's above the town of Newcastle, on the Miramichi River in New Brunswick. Before 10 o'ldock at night it was 20 miles below Newcastle. In nine hours it had destroyed a Itelt of forest 80 miles long and 25 miles wide. Over more than two and a half million acres almo.st every living thing Avas killed. Even the fish were after- wards found dead in heaps along the river banks. Fi\e hundred and ninetv buildings were burned, and a number of towns, including New- castle, Chatham, and Douglastown, were destroyed. One hundred and sixty persons pei'ished and nearly a thou.sand head of stock. The loss from the Miramichi fire is estimated at !?30o.(t(i(». not liicludiMg the value of the tim))er. In the majority of such forest fires as this the destruction of the timber is a more serious loss by far than that of the cattle and build- ings, for it carries with it the impoverishment of a whole region for tens or even hundreds of years afterwards. The loss of the s(um})age value of the timber at the time of the fire is but a small part of the damage to the neighborhood. The wages that would have been caiiied in limibering, added to the value of the produce that would h;ive been purchased to supply the lumber camps, and the taxes that would have been devoted to roads and other jjublic improvements, furnish a uuich truer measure of how nuu-h, sooner or latei-, it costs a region w lieu its forests are destroyed by fiiv. The Peshtigo fire of October. Is71. was still more severe than the Miramichi. It covered an artni of o\('i' 2,(»00 square miles in W'iscon sin, and involved a loss, in timber and other property, of many mil- lions of dollars. Between 1.200 and 1,500 persons perished, including nearly half the population of Peshtigo, at that time a town of 2,00C inhabitants. Other fires of about the same time were most destructive in Michigan. A strip about -tO miles wide and ISO miles long, extending across the central part e checked if they are feeble by beating them out with green liranches ov by raking the leaves away from a narrow strip across their course. The best tool for this purpose i.s a four-tined pitchfork oi' a common stable fork. In sandy regions a thin and narrow belt of sand is easilj* and quickly sprinkled over the ground with a shovel, and will check the spread of a weak fire, or even of a comparatively hot one if there is no wind. Dirt or .sand thrown on a liurning lir<' is one of the best of all means for putting it out. . 29.— A surfiioe (ire burning slowly against lliu wind. soutLern N In den.se forests with a heavy forest floor lires arc t)fteii hot enough not onl}' to kill the standing timl)er but to consume the trunks and branches altogether, and even to follow the roots far clown into the ground. In forests of this kind fire spreads easily, creeping along on the surface or through the dufl' or under the bark of rotting fallen trees. . In the same way it clim])s dead standing trees and ))reaks out in bursts of flame high in the air. Dead trees help powerfully to spread a fire, for in high winds loose pieces of their burning bark are carried to almost incredible distances and drop into the dry forest far ahead, while in calm weather they scatter burning fraguients all about them when they fall. (See lig. 30.) 45 GROUND FIRES. When (he dutl' is \-ery deep or the .soil jjeaty :i tiro miiy burn l)eneath the surfaces of the ground for weeks or even months, .sometimes show- ing it.s pre.sence by a little smoke, sometimes without giving anj' sign of life. Even a heavy rain may fail to quench a tiro of this kind, which often breaks out again long after it i.s believed to be entirely extinct. Fires which thus ))ui-n into the ground can sometimes be Fig. 30. — The effect of repeated fires. Not only the old trees are dead, but the seedlings which succeeded them have perished also. "Western Yellow Pine in the Black Hills Forest Reserve, South Dakota. checked only b}' digging a trench through the layer of decaying wood and other vegetable matter to the mineral .soil beneath. Ground tires usually burn much more .slowly than surface tires, but the}^ are excep- tionally long lived and very hard to put out. It is of the first impor- tance to attack .such fire.s quickly before they have had time t(j l)urrow far beneath the surfact^ of the ground. .Surface fires arc u.sually far 173 4H less troublesome, but in eit-hei' case tires which kill the trees are gen- erally repeated again and again until the dead timber is consumed (tio-. 31). ',*«:,,- ^ Flii. 31.— Tlicrc-Piiltof li-fl wiUicnit BACK FIRING. The most dangerous and destructive forest tires are those which run )oth along the ground and in the tops of the trees. When a tire leconios intensely hot on the uiound, it may run up the bark, especially if the tr(>es are conifers, and burn in the crowns. Such lires are the fiercest and mo.st destructive of all. Traveling sometimes faster than a man can run, the}' consume enormous quantities of \aluable timber, burn fences, build- ings, and domestic animals, and en- danger or even destroy human lives. They can be checked only by rain or change of wind, or by meeting some barrier which they can not pass. A liari'ier of this kind is often made by .starling another tire some .listancc ahead of tlic principal one. This back tire, as it is called, must ))e allowed to l>ui-n only against the wind and toward the main tire, so that when the two tires meet both must Fig. 'SI. — Setting a back tire on the .*;irie of a roarl. Snntiiern New 47 (TO out for liu-k of fuel. To jii-ovt-tit it from nioving- with tho wind, ii haciv fire .should always Im started t)ii tho windward side of a road (tig. .'W) or a raivcd oi- sanded strip, oi' sonic other line which it can lie kept f I'oni crossing. If it i.s allowed to escape it ma}' become as dangerous as the main fire itself. Back fires are sometimes driven beyond control 1>V a change of wind, l)ut the chief danger from their use is caused by t-i^ ~'\ h[ —V liri. hue aloug a railroad with two cleared spates separated by a doublt r w il Irees intended to catth the sparks persons who, in excitement or fright, light tlicm at the wrong time or in the wrong iilace. Still, there is no other means of tighting fires so powerful and none so eti'ectivo when rightly used. FIRE LINES. Fire lines — strips kept free from all inflammable material by burn- ing or otherwise — are ver}- useful in checking small fires and of great value as lines of defense in fighting large ones. They are also very effective in keeping fires out of the woods, as, for example, along railroad tracks (fig. 33). But without men to do the fighting they are of as little u.se against really dangerou.s fires as forts without soldiers against invading armies. iL™^^"^ ""^ CONGRESS l§Mliih'\mm 48 FARMERS' BULLETINS. ^ ®®^ ^^^ 619 thl^^{^i^fi;r^,!f^i:^t;-j;--^ Bulletins avai,a,,l.. fo. distribution, .howin^ application to an; Senator Rp^n^'llfi'^i^-.^A^'V^i":'' ';.' ^^nt to any a.klres, oS application to any S^natorVRepTesentatrve or ni^^e 7'" r.' '*^"' *'^ ""^^ ^'^'^'^-' tary of Agriculture, Wash , "ton nfThl '^•'*^*?''*'' "' ^'ongress, or to the Secre- tinue.1, being superse led SlS bulletins '''"' ""'^''"'"^ '^'■^^" ^'"''■' discon- 16. Leguminous Plant.s. Pn 24 21. Barnyard Manure. Pn 32 ' 9j' S^t?^?,'"l'"S of Farm Animals. Pp 3- 24. Hog Choi era and Swine Plague Pn u to. Peanuts: Culture and Uses, ^Pp 24 27. Flax tor Seed nnd Fil„T Pi, li 28. Weeds; And H 29. Souring and ( 1 30. Grape Diseases SI Alfnlfn, or I ,:r ■ to Kill Til, 11-11 m„lC,„,l I ll. I'n«liirts 1 Milk r|.. 32, Pf. ■■% 57. liii ■>S. Th .59. H,-, Pp. 16. ■ , ■' I's. Pp.12. :.'."'r,:.'o7. ^- "'■'■'■ use. Pp. 24. .Milk. Pp.29. ■'■«nl on tlie Farm, pp 20 I'.Tlili/.Ts. T'p.24. ' ■ "i~ 1" >lp.:!2, \\,,rk-IV, Pp,32. "6. Tomato (; 77, TheLiniir 78, Expr-iirin 79, Expi'iii:, 80, The I '.Ml 81, r..rn 11;' i>, ii; I Soils, Pp,l.. Mii-i, Work-V. Pp, , Uork-Vl, P, ■ I' 1M-, Pp, ],;, II ili'S.uih, Pp,24, Pp.23. lation Work-VII, Pp, 30, ■US Plants, Pp..s2, at ion Work— Vin, Pp, 23. Pp.:!2. Pp. 32, Pp. 12. Pp. 30. 96, Raisin- s 97, Experini. 98, SUTCosti.,1 99, Ii,:-,v, 1-,,, 100, If !■ . p 1 s and Treatment, lion Work— IX Pp, 27. harden. Pp, 24, Farmers, Pp, 47. "iMutton. Pp.48. uli,,„ Work-X. Pp..32. S'lnth.rn Farmers. Pp.48 -oi Shade Trees. Pp,:w 1 I lie South. Pp.40. ]^i y '" ' '■ii.-e Plants. Pp.4,s. 103. l,,.p.in„en(,-latlon Work-X r. Pp. 104. ^otcSOU Frost. Pp.24. ;«?■ g'^Pei'mPlt station Work-xir. Pp 32 106. Breeds of Dairy Cattle. Pp. 4s '^' }nl- I'^P,?"'?™' Station Work-Xlil pp 32 108. Saltbushes. Pp. 20 ' 109. Farmers' Reading Courses Pi, ■•n 110. Rice Culture in th,. r, ,i siatis it, ■>« 111. Farmers' Interest in (i 1 s I ' Pn ^j 112. Bread and Bread Jlakin^- I'p'io ' ' 113. The Apple and How to Grow ii " Pn t) 114. Experiment Station Work— XIV. Pn 28 115. Hop Culture in California. Pp -7 ^' 116. Irrigation in Fruit Growing. Pp. is Pp.'''28 ^^''' """^ ^°''"'' '" "'^ Northwest. 118. Grape Growing in the .South. Pp ,30 U9. Experiment Station Work— XV Pn' 31 120. Insects AfTecliiii; Tobacco Pp so * 121. B, 122. I 123. I ■il: Ii Pi.. :r.' 130 Til. ',1 131 II 132 Tn'i . . 133. lA,.. 1,1 l:!4. Tree PI Pp. 38 135. Sorghun 136. Earth H 137. Tl... Mr I3.S. IlIlL 139. Fill . 140. Pnii.,,,., 141. Pnnllrv 'i'i"''T''T-V"- i"p-32- .1 I roilucts from InjurioiLs irm Buildings. Pp. 4s 1 ides. pp. 42. I'sasFood. Pp. .32 I 'p. 40. 111. Bull Weevil. Pp. so, I 1 I'.i'-lion of (ileoniar- 1. I i:iui,.i-. Pp. 11, 1 . 111.- Wheat, Pp,40, II ".ik— XVIII, Pp. .32 1 Rural School Grounds. 1 Sirup Manufacture. Pp. 40, I'p, 40, ^. Pp. 11; nil,. Fa .Pp, 111 142. The Nidritive and Economic Valm. ,','f i.',„„i. 143. The^hm'formation of Beef and Dairy Cattle, j.ll. ExrHTimentSlatitm Work— XIX Pn 39 i ■ fiK, ;",!', f,''^"""''i'l "-^ "P .Insecticide!^- Pp.ag. I i- u'f,U i- ""'3 '^""Sicides. Pp.16. I ! K r^v^v, 'm"?:: ' ';:!:%"'' '"« «°"'h. pp. 30. Mil' 'r.^I" ■.■•'"";'." ■'^'■"'"? Work-XX. Pp. 32. hii, ( l<..,inii,i;.N,.w Land, Pp.24, 161. Dairying in the South. Pp. 48 la2. Scabies in Cattle. Pp o^ 153. Orchard Enemies in the' Pacifie Northwest. 1.54. Th^e^Fniit Garden: Preparation and Care. 155. llo^wiWects Affect Health in Rural Districts. 156. The Homo Vineyard Pp 24 !-;• 7,'^<'P''0PaPatiori. of Plants, 'pp 24 Pp. '28° ^""" ®°""' ^'"SalUm Ditches, 150, Scab in sheep. 160. Game Laws for 1902. Pp 56 161 Suggestions for Fruit Growers. Pn 28 i?.f i^.^Pf "J"''"' Station Work-X XI. ' 163. Methods of Controlling the Poll Weevil 161. Rape as a Forage Crop: 165. Culture of the Silkworm 166. Cheese Making on the? Farm 167. Cassava. 168. Pearl Millet. ]m gjP^'rae"' Station Work-xxir, Pp.:^2. JZV' Pnnciples of Horse Feeding Pp 44 i-.V J , Control of the Codling Motti.' Pp 24 1 , 2. Scale Insects and Mites on Citrus Trees ' o ^^ LTBRORy or ^ 002 818'^ig^'^