Chapter XIV: Section II: Timbers (9)

Mr Cruickshank next brings forward his plan of raising oak forest, which appears to have been his own invention, although invented before. Whenever mice and other gnawers (glires) are not very abundant, it, if properly executed, would seem to be the best method of raising oak forest; and, indeed, in many situations, the only practicable one. Mr Cruickshank’s method coincides nearly with Mr Sang’s, only he does not carry his system of protection so far as Mr Sang, in first raising belts of the most hardy kinds of timber, distributed to windward of, and intersecting the place intended to be planted, in such a manner as to afford the best possible shelter from the coldest most destructive {352} winds. Mr Cruickshank, who has never carried his plan into execution, except in an experiment embracing a few yards, directs that the ground intended for oak forest should first be planted with Scots fir and larch, about 4000 to the acre, by the single-notch process, previously described, which can be accomplished under L. 1 per acre. As soon as these have risen to four feet in height, he prepares patches about two feet square and ten feet distant in the interstices, by digging the soil over, and mixing a spadeful of slaked lime carefully with the mould, taking out a tree whenever the interstices do not suit for the patches. He then plants, in the end of March or beginning of April, five acorns in each patch, about an inch deep, one in the centre, and the other four in the angles of a foot square, and gives them no farther attention for two years, except removing any overhanging low fir branch. He then goes over the patches, cutting out all the supernumerary plants, a few inches below the surface, leaving the most promising one on each patch, being very careful not to disturb any of its roots in cutting out the others. As these oak plants extend in size, he gradually removes the fir.

Excepting the bare plan itself, which is certainly very plausible, there is nothing in the description {353} of the practice—the preparation of the patches of ground to receive the seed and the subsequent management—which merits attention. His very particular interdiction of the use of manure is, to say the least of it, injudicious—as if it signified to the plant whether it were forced by the use of lime, or by a little putrescent manure, both of which Mr Withers would consider very advantageous; or as if there were much fear on our poor exposed wastes of erring on the side of rendering the plant delicate from over luxuriance; its constitution, on the contrary, would rather be strengthened. Mr Cruickshank, in directing the removal of the fir nurses, one thousand per acre to stand till they have reached twenty-five years, fit for roofing of cottages, and similar purposes; and five hundred till they have reached thirty-five years; his dividing a slaked boll of lime into five hundred spadefuls; and his bestowing no hoeing or weeding upon his seedlings, would show, without his admitting it, that he had never practised this mode of forming plantation.

Prefacing this system of rearing oak forest, Mr Cruickshank in rather a clever manner points out its advantages, and also the disadvantages and consequent failures of _planting_ young oak trees in exposed situations. But after all his eulogy, we think he has {354} left something unsaid. The great disadvantage attending transplanting oaks to situations not very favourable to their growth, is, that the plant which, under any circumstances, receives irreparable and often mortal harm, from the severe injuries of removal, has to contend, in this mutilated condition, at the same time with the uninjured occupiers of the soil (the nurses or the native weeds), and with the unpropitious situation; whereas, when the plant springs up from the acorn a native, especially when it is assisted at first by weeding or hoeing, the part above ground being always in proportion to that below, and receiving due nourishment, it contends with the occupiers on more equal terms, and encounters the sterility of the soil, or the severity of the climate, with all its natural powers unimpaired.

As it is the natural condition of the seedling to grow up under the shelter of the parent tree, so also does it happen, that it rises under this shelter with greater luxuriance and vigour than when exposed to the evaporation, and parching sun, and battering wind, of the bare country.

We have admired the beautiful, straight, luxuriant, shoots of the young hollies, thrown out under shelter, and have compared them with the dry stunted shoots of the young holly in the open country, though in the former case their roots had to contend {355} with the roots of larger trees, and in the latter they had the soil to themselves. Experience has proved, that in exposed bleak situations, shelter is necessary to young plants. Transplanted oaks among the roots of young trees, so large as to afford sufficient shelter, very frequently do not succeed, at least without the utmost care in the transplanting, and a considerable deal of labour to prevent the roots of the shelter trees from starving the transplanted ones, unless a very propitious moist summer follow the transplanting. Raising from the seed, which obviates all this, seems therefore the only conveniently practicable way. Yet it must be owned, that the system of raising forests _in situ_ from the seed, appears, as yet, much more successful on paper than on our hills and moors.

In endeavouring to confute the opinion, that the oak will not grow throughout Scotland, but in the milder and more propitious situations, Mr Cruickshank adduces the well-known fact, that large oak timber is found in almost every peat-moss.

This is a fact worth tracing to its cause. Under Nature’s own conduct, trees advance considerably further into elevated or cold inhospitable regions, than they would otherwise do, by means of the mutual shelter, and of the more hardy kinds acting as an advance guard. Yet there is a limit to this, as the {356} power of ripening seed is not increased by shelter in proportion to the power of growing—perhaps not at all; we instance the Spanish chestnut, which has scarcely ever been known to ripen seed in Scotland. Seed-grown trees will, therefore, under Nature’s arrangement, not be found extending much beyond _the line of seed ripening_. From nuts, acorns, and other seeds, fully developed, being found in elevated mosses in this country, other causes than shelter appear to have existed.

Before this country was so much overrun by men and oxen, a great deal of timber had existed, covering much of the superior land which is now under tillage. This consisted chiefly of the oak, Scots fir, birch, hazel, and alder,—the oak extending northward and to elevations, and ripening seed, and attaining to a size which it does not now do, either wild or cultivated, in the same latitude, neither here nor in any other portion of the world; which, along with some other facts, lead to the supposition, that the climate has changed a little,—in part, possibly, as we have before stated, from the gradual formation of peat, to which, overthrown oak forest, from the abundance of the tannin principle, has a great disposing influence, even under a warmer climate than present Scotland. The highest latitude to which a tree, or any other kind of plant, reproducing by seed, {357} naturally extends, depending on the ripening of the seed, and also on the power of occupancy, is however different from that where it will grow, when ripe seeds are procured from the coldest place where they ripen, and all the competitors removed; and under the system of shelter belts, hardy pine nurses, and seeds from the nearest place where they ripen, we have no doubt that oaks may be extended to a colder situation than Nature herself would have placed them in. For the higher more bleak portion of the country, we would recommend acorns grown in Scotland, in preference to those imported from England. We have several times observed wheat, the seed of which had been imported from England, sustain blight and other injuries in a cold moist autumn, when a portion of the same field, sown of Scots seed, at the same time as the other, and under the very same circumstances, was entirely free from injury. English acorns are also frequently heated in the casks in which they are imported, which must impair their vigour[66]. {358}

The part of Mr Cruickshank’s volume which we have analyzed, does not extend much beyond the first half: this portion is well worth a perusal. We have merely glanced over the remainder: it is a make-up scarce worth noticing. The language, on the whole, is easy and plain; and although the volume contains a considerable number of errors, in the pointing out of which we have not been sparing, yet will it form an excellent planter’s assistant to people who have ground to plant, and are ignorant of the process of planting.

* * * * *

We have now brought before the reader a pretty fair picture of the Forestry of the present day. Some may wonder that the written science of arboriculture should be so imperfect and inaccurate; but the knowledge of the art, and the power of communicating that knowledge, are of so different a {359} character, it not unfrequently happens, that those write who cannot act, and those who can, are incompetent to write—sometimes unwilling; besides, correct opinions on this subject, as on most others, are only just beginning to be formed. We have endeavoured to assist in disentangling the correct from the erroneous. It is impossible for the most wary always to avoid misconception of facts, but man merits the name of rational only, when he evinces a readiness to break from those misconceptions, to which the narrow-minded, the proud, the vain, and the creature of habit and instinct, cling so obstinately. As a friend, we have stood on no ceremony with our brother arboriculturists. We have laid ourselves open to their criticism, and we hope they will shew as little ceremony with us.

ENDNOTES TO PART IV.

[36] This repetition of our directions on pruning is intentional—“Carthago est delenda.”

[37] The coniferæ have a weaker or more connected vitality than most other trees—the whole individual participating in the injury of any part. Perhaps this arises from the liability of resinous juice to putrescency—any putrid affection in one spot of the more vital part of the tree spreading quickly over the whole.

[38] Transplanting having an opposite influence on the young of herbaceous and woody vegetables, in the former when not already rising into stem, retarding, and the latter accelerating or furthering development of the reproductory parts, is a good lesson to reasoners from analogy. The root-fractured herbaceous plants repairing the injury almost immediately, and before the rudiments of the reproductory parts have time for expansion, the greater quantity of moist nourishment afforded by the unsought newly stirred soil, produces a flush of radical leaves, which react to further the extension of the roots. The new rootlets have again more connexion to promote the growth of the radical leaves, and to induce offsets—_tillering_—from the sides of the bulb, than to nourish or mature the core part, from whence the stem arises—a certain comparative extension and maturity of the core being necessary to the rising of the stem. Thence seeding can be retarded, and life in annuals be continued, _ad libitum_. On the contrary, in woody vegetables of perennial stem, the reparation of the root-injury takes place slowly, and the evaporation from the stem and elevated branches and leaves exhausting the little moisture afforded by the inadequate root-suction during an entire season, gives time and bias for the germs to pass into reproductory instead of productory organs even the first season.

[39] We rather think Mr Sang mentions this.

[40] They say a better management has lately been established. This may be followed for a short time in the high stream of the agitation, or while the present heads of management remain in power; but the system, we fear, contains the seeds of evil, which, like the weeds, will soon overwhelm the alien good.

[41] The inferior growth of the part of a hedge which was pruned before the vegetation had begun, may be ascribed to the vital action having been checked at the commencement by the destruction of the buds necessary to stimulate this action; and being deprived of this first strong impulse, life had remained languid throughout the season, the roots never recovering their proper suction or foraging power;—when the pruning was later, a sufficient stimulus had already been given.

[42] Vide Sir Walter Scott.

[43] The want of the annual layers of cellular tissue of wood, exterior to and separating the annual lineal tubes, is so complete in some cases of slow growth, that the timber seems only a light congeries of tubes, without arrangement; hence the age of the tree cannot be determined but by a section of the root-bulb, where the growths are larger, and the deposits regular.

[44] The climate of a country in regard to annual steadiness, can be pretty accurately determined by the appearance of the annual layers of trees, especially of the pine tribe; and in a new settlement where great difference of size of layer, and of resinous deposit is observed, we may be pretty certain the seasons are not steady, or that insect depredations or blights occur; and a reserve of food ought always to be retained. By careful inspection of the nature of the annual wood deposit, or of the locality with regard to moisture, it may be ascertained, whether the irregularity has been owing to difference of temperature, or of moisture. In warm climates the irregularity will generally depend on drought and moisture, and in cold climates on heat and cold; though sometimes the depredations of insects, such as locusts, or of blights, may be the cause.

[45] Though we give this experiment, we admit that little dependence can be placed upon a single fact. The trees must have been different in variety, and probably in sex, both of which may occasion a discrepancy.

[46] The time the weight is in suspension, must be attended to. A beam will support a much greater weight during a minute than during an hour; and two beams may be found, the one capable of supporting the greatest weight during a minute, and the other the greatest during an hour.

[47] We shall not here introduce the interminable discussion of dry-rot, as it remains to be proved that moderately fast grown young timber is at all more liable to dry-rot than small-growthed old, provided the sap-wood be entirely removed.

[48] In fairness, it may be proper to explain, that the greater part of the trees we have thus cultivated have been of _Pyrus_, although we commenced the practice with common forest trees—yet the pear and apple vary nothing from the oak and ash in the primary stage of life, in as far as respects the extension—we can also profit fully as much by raising apple timber of proper fast grown variety, as by any other timber; and have it in our power to sell this timber to machine-makers at double the price of oak of the same size.

[49] We think Sir Henry would find some of the failures of which he owns he cannot well ascertain the cause, but occurring especially in beech and oak, to be owing to a number of the lower roots, which are by far the tenderest, being bruised by the weight of the tree itself, when he turns it repeatedly over from the one side to the other, in order, by throwing in earth beneath it, to raise the root on a level with the surface of the field, the whole weight of the incumbent mass resting upon these soft roots. The oak, and still more the beech, are exceedingly susceptible to injury from cutting or bruises, and die far inward from the laceration. The wounded lower roots, especially when any vacuity is left not filled close in with earth, where mouldiness might generate in a dry situation, or when soaking in moisture for a part of the season, will become corrupted; the putrefaction thence gradually extending upward into the bulb, will contaminate the whole, and the second or third year after planting, the tree will be dead.

[50] We understand freezing the earth around the bulb is an old practice.

[51] We particularize the oak, cork-tree of arid warm Spain, and much of the timber of New Holland. Owing to the hot parching air in the latter place, the epidermis becomes dried to such a degree, that contracting by the drought, and bursting by the swelling of the enveloped stem, it peels off like the old skin of a serpent, and is often seen hanging upon the tree in large shreds like tattered garments. In several kinds of trees, we have counted regular annual rings of desiccated bark; in some kinds this appeared a growth or deposition, in others, mere parched exuviæ. Trees attain some age before the _exuviæ_ commence; the _deposit_ begins the first season, even in sheltered situations. The cork-tree, and the small-leaved elm, shew the greatest annual deposit of dry bark. The former does, and the latter is said to belong to warm arid countries; both form a better nonconductor of heat than any other dry bark we are acquainted with—infinitely better than the bark exuviæ of trees which approach the polar regions.

[52] We do not pretend to explain how it is, that one kind of climbing plant follows the sun in its convolutions, and another traverses his course. There surely cannot be any thing in a habit acquired in the southern hemisphere.

[53] In proceeding further on in Sir Henry’s volume, we have noticed an excellent observation quoted from Du Hamel: “The extension of the shoot is inversely as its induration, rapid while it remains herbaceous, but slow as it is converted into wood. Hence moisture and shade are the circumstances, of all others, the most favourable to elongation, because they prevent induration or retard it.” Although quoting this, Sir Henry recurs to his old opinions, and proceeds to observe, “Trees so circumstanced, push upward to the light; and from the warmth which their situation affords, their stems being thin and slender in proportion to their height, they are destitute of strength to resist the winds.”

[54] We do not mention temperature, because we are not in possession of facts sufficient to lead us to form an opinion on the subject. Judging from animal analogy, of which our author is so fond, we notice, that those animals exposed in open atmosphere, have generally warmer blood than those who lurk in holes,—even than those of the same species who happen to live under shelter. Now evaporation takes place from animals as well as from vegetables, and the consequent cold is more than balanced by the heat of what may be termed the vital fire, which, like most other fires, burns brightest on exposure to a current of atmospheric air, being increased either by the result of the new chemical combinations having less capacity for heat, or by the stimulus of the fresh moving air exciting the vital action. Of the general influence of close forest on temperature, we are also not very well assured; but the few facts which observation has afforded, lead to the opinion, that to the northward of 50 deg. Lat. forests have higher temperature than bare country; that from about 50 to 30 degrees Lat. forests are cooler in winter and warmer in summer; and that nearer the equator, forests are generally cooler than bare country. But the temperature is regulated so much by the position of seas and lakes, in combination with the prevailing currents and strength of currents of the air—by the configuration of the country,—moisture and cloudiness of the atmosphere and quantity of rain,—by the composition, arrangement, and colour of the soil,—by the lower vegetable cover, and even by the nature of the forest itself, whether deciduous or evergreen, that particular facts must be very carefully weighed to enable us to reach general conclusions. It is generally understood, that forests render the climate moister.

[55] Our experiments have not yet been carried so far, as to determine if, by any arrangement of drying or exposure, they may be seasoned to sustain intense frost, which may affect them differently from moderate frost, either by causing complete congelation of all their structure (moderate freezing appearing only to congeal their fluids, but not entirely the containing vessel, at least only partly congealing the mass), or by killing the vital principle itself through nervous affection. The potatoes became green from the exposure to the light, and we rather think acquired greater hardihood of constitution, or greater vitality or excitability by the exposure, thence greater power to resist the cold, independent of the disposition they acquired by desiccation to endure it.

[56] Is the rending of the stems of trees, during intense frost, internal only, and occasioned by the alburnum expanding more by congelation than the drier mature wood? or, is it external, and caused by the contractile effect of the dry air and cold on the alburnum rendering it insufficient to surround the mature wood, which, from dryness and want of living susceptibility, may not contract so much.

[57] The fineness of vessel or fibre of the Siberian crab, may be induced by the arid warm air, the continued radiation of heat and light upon the portion above ground, and the coldness of the ground around the roots during the short summer in Siberia, where the air and surface of the ground is warm, and vegetation progressive, while the ground remains frozen at a small depth. Like all varieties of plants habituated to colder climate, the Siberian crab developes its leaves under less heat than varieties of the same kind which have been habituated to milder climate.

[58] We have not taken Sir Henry in the literal sense. Timber is well known to decay sooner in a warm than in a cold country, _cæteris paribus_.

[59] See Appendix F.

[60] The preliminary sentence is very vaguely worded; we suppose, “increasing the annual circles,” means increasing them in thickness, not general contents of length multiplied by thickness. But even in the latter sense, we hold pruning tends generally to diminish the annual circles.

[61] It is a theory of Mr Sheriff, Mungo’s Wells, that all plants have excrementitious deposit from the roots, the deposit from one kind affording a good manure to another kind. Thence the advantage of mixed grasses and legumes in pastures, and of the rotation of different kinds of crops.

[62] Vegetable soil is sometimes buried deep under volcanic mud, sand, and ashes, or mixed with the subsoil by earthquakes. In some districts of South America, the country, from being fertile, has been recently reduced to sterility, by the vegetable mould being so much scattered through the subsoil by repeated upheavings and tossings about by earthquakes, as to be out of the reach of plants.

[63] There is a deposition from the atmosphere of saline matter going on at the surface of the earth, either evaporated from the ocean, and falling with the rain and dews, or formed by gaseous combinations—most probably both. In countries where the quantity of rain is insufficient to wash this saline accumulation away into the ocean as fast as it is formed, it increases to such a degree as almost to prevent vegetation, only a few of what are termed saline plants appearing. This saline accumulation in warm dry countries, bears considerable analogy to tannin deposit in cold countries.

[64] The matured timber of the larch, in some cases, remains for a considerable time stained before the rot proceeds rapidly; in other cases, the rot makes quick progress; in this rapid decomposition, certain kinds of fungi assist greatly. When once seated, they seem to form a putrid atmosphere or tainted circle around them, either by their living exhalations, or corrupt emanations when dead, which is poisonous to the less vital parts of superior life, and also expedites the commencement of decay in sound dead organic matter, such as timber, thus furthering the decomposition so far as to render it suitable food for their foul appetite, and paving the way to their further progress.

How their seeds enter into the heart of a growing tree having no external rottenness, is not very obvious, unless they are inhaled or imbibed by the root tendrils: from the resemblance which the growth of some of them has to fermentation, it is not even very improbable that the animalcules of supposed molecular or inferior life, have, of themselves, a disposition to unite into some of these aggregates without the presence of any disposing germ.

The modifications of material attractions, by the varied germs of superior life—the fixity of some of these deposites after life is gone—the resolution of these into inferior animalcular, or even molecular, life—and the instrumentality of zoophytes of the lower order of organization, in hastening this decomposition by the balancing of the attractions of this secondary life, afford a wide field for investigation. Those uncouth sportings of nature quickly appear and disappear as _material_ spectres, feeding on corruption, and mocking at primary life.

[65] We have raised crops among young trees (as well timber as fruit trees), not four yards apart, by plough culture, and have found the process, after the ploughmen and horses were accustomed to it, not much more expensive than common cultivation, and the crop, till the trees became too close, scarcely inferior. By means of a long _muzzle_ to the plough standing out towards the left side, and a driver to the horses beside the ploughman, we succeeded in getting the two first furrows lapped a little over each other in the row of trees, where the gathering of the ridge commenced (we gathered up at every other row). In the row of trees where the finishing of the ploughing of the ridge occurred, we were obliged to leave a stripe of ground about two feet wide, to be dug by the spade. The horses required to be yoked in file, and to drag by ropes (traces) rather than by chains, as the bark of the trees was liable to be rubbed off by the latter. The more to guard against rubbing, we had the _swingletree_ constructed so that the trace-ropes came out from a hole in the ends, without any hook. In harrowing the ground, one man is required to lead the horses, and another to direct the harrows. In rich soil, under cultivation of green crop, in this manner, trees progress very rapidly, and from the open arrangement acquire very healthy constitutions. Of course, when not coniferæ, the plants require a little more attention to train to one leader and equality of feeders, than when close planted. We should consider plough cultivation of young woods, provided ploughmen as expert and careful as the Scots could be obtained, much more worthy the attention of the English planter than the Withers’ system (trenching). Need we mention, that in green crop, every thing depends upon plenty of manure and of well-timed plough and horse hoe labour? Excepting in the case of larch, we should dread no injury to the trees or timber from plenty of manure.

[66] We are indebted to our friend Mr Gorrie, Annat Garden, for the fact, that English acorns throw up a much more luxuriant stem than the Scots; they forming a step of several inches when planted next each other in the nursery line. We should consider this to arise from the largeness of the rudiments of the plant, and greater quantity of garnered nourishment in the English acorns, which are nearly double the size of the Scots, our present climate being insufficient for the proper development. This leads to the question, will the greater luxuriance balance any tenderness from want of acclimatizing? Would the oak keep its present locality in Scotland if left to nature? A careful inspection of the most elevated peat mosses in which remains of timber exist, and a comparison of the size of the seeds found there, with that of those of the present day, grown the nearest to this in situation, would resolve the question of refrigeration.