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no large oaks were bitten off for two years afterwards. From this relation of what occurred in a place where mice were so abundant, it does not appear to us that any general conclusion can be drawn against the use of acorns instead of plants; because, according to the same writer, the mice were equally effective in gnawing through trees 6 ft. or 8 ft. high, which, by a parity of reasoning, would afford an argument against the use of oak plants. The relation, however, is of great importance, as showing the numerous natural enemies of the seeds of trees, and also of young trees, which the cultivator requires to guard against. As neither the mice nor the other vermin mentioned are peculiar to the oak tree, we shall not here enter on the different modes of deterring vermin from injuring trees, or of destroying them, but refer our readers to this subject in the Encyclopædia of Arboriculture.
Pruning and Training. The common oak, in the nursery, will not bear severe pruning; nor is this of much use with a view to training the plant to a single stem, because, in almost every case of transplanting the oak to where it is finally to remain, it is found to make the clearest stem, and the most rapid progress, by cutting it down to the ground after it has been some years established. In plantations, or in single rows, the oak, even when a considerable tree, does not bear pruning and lopping so readily as the elm; but still it may be trained to a single stem, which should be of considerable height when the object is to produce plank timber; but short, when the object is to throw strength into the head, in order to produce crooked pieces for ship-building. These crooked pieces for ship timber are generally the result of accident; but there seems to be no reason why trees should not be trained by art to produce crooked stems, as well as straight ones. We are informed that, in the government plantations, in the Forest of Dean, there are some hundreds of acres of planted oaks, which have never been pruned in the slightest degree, that have perfectly clear trunks from 50 ft. to 60 ft. in height. These trees were planted thick, towards the end of the last century, and were gradually thinned out, as they advanced in size; and their side branches have died off, being suffocated by the surrounding trees. We shall notice here the modes which have been adopted or recommended for producing crooked, or what is called knee, timber, in the case of the oak; and, in our chapter on training trees generally, in our Encyclopædia of Arboriculture, we shall go into details.
Training the Oak for crooked, or Knee, Timber. Various schemes of training and pruning the oak, so as to produce crooked limbs of large dimensions, have been proposed by Marshall, Pontey, Billington, Matthew, and other writers. South, in the Bath Society's Papers, thus accounts for the production of crooked timber by natural means:- "Trees," he says, "dispersed over open commons and extensive wastes, have hitherto produced the choicest timber." Whoever traverses a woody waste, "with the eye of curiosity awake, must remark that almost every thorn becomes a nurse for a timber tree. Acorns, or beech mast, or sometimes both, dropped by birds or squirrels, vegetate freely under the shade and protection of the bushes, till they rise above the bite of cattle. Small groups and single trees are thus produced; their guardian thorns, when overpowered, perishing. Then the timber trees having open space for their roots to range in, their growth becomes rapid, their bodies bulky, their limbs large and extensive; cattle resort to them for shelter, enrich the ground with their droppings; and the timber, deriving advantage from the manure, becomes productive of knees, crooks, and compass pieces, the chief requisites in naval architecture." The French, this writer observes, have endeavoured to form kneed timber artificially, " by suspending weights to the heads of tender saplings, bowing them hastily to the ground; which is not only an expensive, but an inefficacious method; for it injures the plant, by straining the bark and rupturing the sap-vessels." (Bath Soc. Papers, vol. vi. p. 54.) Preferring the natural method of producing crooked timber, Mr. South continues,-"Parks and pleasure-grounds might be rendered enchantingly beautiful by being planted with clumps of quicksets, black thorns, hollies, &c., interspersed here and there, for the protection of acorns purposed to be sown
among them. Under their protection, oak saplings, which delight in sheltered places, would thrive exceedingly; be safe from the browzing of cattle, without the expense of fencing; and the lawns would become wooded with stately timber. When oaks are planted in groups, one or other often gains the mastery, or forces the rest to bend forward till they have room for ascent. Trees in groups, when few in number, enjoy a liberty nearly equal to single ones: each tree has a space where its roots may draw nutrition; and, as these and the branches usually follow the same direction, the leading roots of the exterior trees will tend outwards; and, finding nothing to obstruct their passage, will furnish supply sufficient to keep their trunks thriving, notwithstanding superiority of their antagonists. Hence it is manifest, that any quick-growing trees of small value may be used as instruments for forcing seedling oaks out of their upright line. Cuttings of coppice withy (Salix càprea) will, by the freedom of their growth, overpower the saplings, bearing them down almost to the ground for a time; and, the purpose being effected, may, for relief of the oaks, be cut down as often as requisite; till, as the oaks gain power, the withies, in their turn, give way. Plants like these, which extract nutrition of a different nature, though they promote a crook, will not starve or check the oaks beneath them. Trees growing out of a bank frequently take a favourable turn such are accepted by the king's purveyors as compass pieces, which gain admission into the dockyards, though of less dimensions, and at a higher price than straighter timber. It may be proper, therefore, in new enclosures, to throw up the banks high and broad; to plant quicksets on the outer slopes, and on the tops withies; and, at due distances near the base of the inner slopes, to dib in acorns, which in their future growth must incline forwards, to avoid the projecting withies, and be some years before they can attempt a perpendicular growth. In such cases the crook will be near the but end, in the stoutest part of the timber, and the curve, thus formed in infancy, will retain its shape as long as the tree endures." (Ibid., p. 59.)
Marshall has the following judicious observations on this subject:-" In forests and other wastes, whether public or appropriated, especially where the soil is of a deep clayey nature, oaks will rise spontaneously from seeds that happen to be dropped, if the seedling plants should be in situations where they are defended by underwood or rough bushes from the bite of pasturing animals; and some few of the plants thus fortuitously raised may chance to take the form desired by the ship carpenter; but this is all mere matter of accident. By freeing the stems of young trees from side shoots, and by keeping their leaders single, a length of stem is with certainty obtained; and, by afterwards checking their right growth, and throwing the main strength of the head into one principal bough (by checking, not removing, the rest), a crookedness of timber is with the same certainty produced; and, what is equally necessary in ship timber, a cleanness and evenness of contexture results at the same time. The dangerous, and too often, we fear, fatal, defect caused by the decayed trunks of dead stem boughs being overgrown and hidden under a shell of sound timber (a defect which every fortuitous tree is liable to) is, by this provident treatment, avoided: the timber, from the pith to the sap, becoming uniformly sound, and of equal strength and durability." (Pl. and Rur. Or., vol. i. p. 141.) Billington produced crooked timber, in His Majesty's wood at Chopwell, in Durham, by fastening oak trees, that were not too strong to be hurt in bending, to larch trees, and keeping them " in a bent position for about two years.' He tied the oaks to the larches with twisted withs, tarred twine, or matting; but, as he does not inform us in what state the trees were eight or ten years after having been subjected to this operation, his experiment may be considered as having been only commenced. He gives directions, illustrated by woodcuts, for pruning off the smaller branches from the larger ones, so as to leave the head of the tree with only three or four large arms, instead of a multitude of branches; and this operation, if commenced in time, and the side branches cut off when not above 1 in. in diameter, promises to be of use. We have heard nothing of these trees since, finding, on enquiry at the Office of Woods
and Forests, that the plan was merely a scheme of Mr. Billington's, carried into execution on a limited scale, in the way of experiment.
Matthew says, "The easiest way to procure good oak knees is to look out in hedgerow and open forest for plants which divide into two or four leaders, from 5ft. to 10 ft. above ground; and, should the leaders not diverge sufficiently, to train them as horizontally as possible for several feet, by rods stretching across the top, or by fixing them down by stakes." (Ón Naval Timber, &c., p. 26.)
That timber trees should be trained according to the kind of timber which it is desirable that they ought to produce, is as correct, as a general principle, as that the different kinds of fruit trees ought to be trained in a manner the most suitable for producing their respective kinds of fruit; but the subject of training forest trees is as yet in its infancy, and the circumstance that iron and other metals can be substituted for crooked pieces, as Mr. Snodgrass, Sir Robert Seppings, and others have shown, is at present rather against the progress of this department of the forester's art.
The Age at which Oak Timber ought to be felled, with a View to Profit, must depend on the soil and climate in which the tree is grown, as well as on other circumstances. Whenever the tree has arrived at that period of its growth, that the annual increase does not amount in value to the marketable interest of the money which, at the time, the tree would produce if cut down, then it would appear more profitable to cut it down than to let it stand. Perhaps it would not be difficult to construct a table, to show the proportion between the annual increase of the trunk at a certain distance from the ground, and the annual amount of timber added to the tree; and, the price of timber and bark being known, a calculation might thus readily be made of the total value of the tree, and the total value of the annual increase. We are not aware, however, that any such table has been calculated; but the idea of it may be useful to proprietors of trees, with a view to felling them. A writer in the Gardener's Magazine states that Mr. Larkin, an eminent purveyor of timber for ship-building, stated, when examined before the East India Shipping Committee, that, in situations the most favourable for ship timber (the Weald of Kent, for example), the most profitable time to cut oak was at 90 years old; as, though the largest scantlings were produced at 130 years' growth, the increase in the 40 additional years did not pay 2 per cent. (Gard. Mag., vol. xi. p. 690.) In Lord Melville's Letter to Spencer Perceval, Esq., when the latter was prime minister, he says that, "for naval purposes, oak trees require to be from 80 to 150 years of age, according to the quality of the soil in which they are grown." (Letter, &c., p. 3.) The Rev. W.T. Bree observes that, as the oak, like all other trees, varies exceedingly in its growth, according to soil and situation, &c., no one fixed period can be given for cutting it down, applicable to all, or even to the generality of cases. A practised eye, he says, will be able readily to decide when a tree is ripe for the axe. "There will no longer be any vigorous shoots in the extremities of the branches; but, instead of this, a curling or crinkling of the spray, with scarcely any perceptible growth: dead branches or small ones will occasionally be seen towards the top; and, above all, the bark will cease to expand, and, of course, will no longer exhibit those light red or yellow perpendicular streaks in its crevices, which are a certain proof of its expansion, and of the consequent growth of the wood beneath." As to the question at what age oaks should be cut down, so as to make the best return in point of profit, this will depend mainly on the demand for oak timber of this or that particular size and quality in each neighbourhood. (Gard. Mag., vol. xi. p. 550.)
Felling the Oak for Timber. On account of the great value of oak bark, the operation of felling is generally performed in spring, when the sap is up, in order to admit of the bark being readily separated from the wood. It is commonly alleged, that felling, at this season, must be highly injurious to the timber; but, when it is considered that the sap ascends only in the soft, or outside, wood, and that it may be evaporated from it by sufficient exposure to the
atmosphere after the bark is removed, the injury to even the sap wood must be trifling if this evaporation is allowed to take place, and the hard wood can sustain no injury at all. It has also been recommended to bark oak trees before cutting them down, and to leave them standing for a year afterwards; but this can be attended with no other advantage than that of evaporating the sap from the outside wood more rapidly than would otherwise be the case; and this rapid evaporation is, in some seasons and situations, and especially in warm climates, apt to produce rents and clefts in the trunk and boughs of the trees. Nichols, who had great experience as a purveyor of oak timber for the navy, found that, by divesting trees, before they are fully seasoned, of their sappy coats, the exterior parts of the wood, or heart, by exposure to the air, suddenly contract, and shut up their pores, so as to prevent the escape of the internal juices: hence a fermentation soon begins, and rottenness is the certain consequence, This does not happen when timber is seasoned with its sap on; the outward parts of the wood not being then suddenly contracted, on accounted of being sheltered from the sun and wind by the coats of sap which surround it, and the juices freely evaporating through the spongy substance of the sap. (Meth., &c., p. 45.) "Oak timber, cut into lengths, and sided (squared on the sides), soon after it is felled," he says, "and laid up in piles till wanted for use, is often found, in the dock-yards, very defective and rotten, particularly at the heart. The annual coats of wood of which trees are composed, and which encompass them like hoops, and hold them together, are in part cut off; and the juices flying off very quick, frequently cause them to split or crack, and the cracks or fissures receive the wet, which soon bring on rottenness." (Ibid.) "By long experience," he continues, "it is unequivocally proved, that the best way hitherto known of keeping or seasoning oak timber, previously to its being used in ship-building, is in a rough hewed state, with its sap on; not only on account of applying it, when wanted, to the most profitable uses, but by lying in the sap for two, three, or more years, it seasons gradually, and never splits or opens, as it frequently does when the sap is taken off, by siding or cornering it when green, and laying it in piles, and whereby it receives very considerable damage, and very often is entirely spoiled. This is never the case if it be suffered to season in the sap: for, though the sap is certain to perish and moulder away in a few years, let it be treated in whatever manner it may with a view to prevent its perishing, still the heart will be greatly improved by this mode of treatment, and, I believe, will endure many years longer for it; and certainly, when it is connected, it will have the great advantage of not twisting and flying about, as when worked green." (Ibid., p. 43.) With respect to the practice of stripping oak trees standing, Mr. Nichols is clearly of opinion that it is of little or no use in rendering the sap wood as good as heart wood. He relates an instance of an oak which was stripped of its bark in the spring of 1784, and felled in the spring of 1788. "The tree," he says, "appeared, by the number of its annual coats, to have been 110 years old at the time of its being stripped; it contained 21 coats of sap, which were in a perishing state; so that the notion which some have entertained, that the sappy parts of oak trees become as hard or equal to the heart for strength and durability, by the ope ration of stripping them standing of their bark, and letting them remain till they die before they are felled, is chimerical." (p. 73.) "The Count de Buffon has incontestably proved, by his experiments, that, by stripping oak trees of their bark standing, and letting them remain till they die, before they are felled, the heart, or perfect wood, thereof will be considerably increased in strength and density; and it is also proved by experience, that the sappy part, or imperfect wood, will not be much altered thereby; at first, and while it is green, it will be found harder and stronger than the sap of trees felled in the usual way; but after a little time, and as the juices evaporate and fly off, it will perish and moulder away, as the sap of oak trees always will do, let them be treated in whatever manner they may with a view to prevent it. Every experienced ship-builder or carpenter well knows that wherever any
sap is worked with the heart of oak (as it sometimes is), it will ultimately tend to weaken and injure the building wherein it is used; for, however fair and well it may appear at first, it will most assuredly decay in a short time." (p. 75.) "For want of examining the original thickness of the sap [wood] of oak trees, and the progress of its decay, and from finding so much of young trees wasted by the decaying of their sappy coats (which generally occupy a considerable space, particularly if the trees were very vigorous at the time of their being felled), some have been led to imagine that, by trees lying for any length of time, the sap [wood] increases in its thickness, or that part of the heart is transformed into sap again, which is by no means the fact; and, if any part of the heart were subject to such change by so lying, there can be no reason assigned why, in the process of time, the whole should not undergo the like change: but this is absurd, and contradicted by experience; for, after the sappy parts are once formed into perfect wood, it ever remains in that state until it naturally decays." (p. 76.)
In felling oak trees the heads of which contain crooked pieces fit for particular purposes in ship-building, care should be taken either to cause the tree to fall on a side that will not injure the crooks, or to separate the branches containing these before cutting down the trunk. South mentions the Langley Oak, which was felled in 1758, in the New Forest, and which had a large head, full of knees and crooks. He thus describes the mode in which these were preserved :- "The knees and crooks were cut off, one by one, whilst the tree was standing, and lowered by tackles, to prevent their breaking. The two largest arms were sawed off at such distances from the bole as to make firstrate knees; scaffolds were then erected, and two pit-saws being braced together, the body was first cut across, half through, at the bottom, and then sawed down the middle, perpendicularly, between the two stumps of arms that had been left, at the end of one of which stood a perpendicular bough, bigger than most timber trees. To prevent this being injured, a bed was made of some hundreds of faggots, to catch it when it fell." (Bath Society's Papers, vol. vi. p. 8.)
Oak Copse is cut down at various periods between 15 and 30 years; the rule being, that the principal stems of the plants, at 1 ft. from the ground, should not be less than 6 in. in diameter. In favourable soils in the south and west of England, this size will be obtained in from 12 to 15 years; as, for example, at Moccas Court; but in the colder climate, and in the inferior soil, of the Highlands of Scotland, from 25 to 30 years are required. The cutting over of copse is performed at the same season as that in which full-grown trees are felled, when in both cases the bark is an object as well as the timber; but, in the cutting over of coppice trees, it is necessary to bear in mind, that the stools are intended to shoot up again, so as to produce another crop. To facilitate this, they require to be cut over smoothly, so as not to lodge water; and close to the ground, in order that the shoots for future branches may proceed at once from the roots, and not at some distance over them; in which case they would be liable to be blown off. (See the chapter on coppice wood, in the Encyclopædia of Arboriculture.)
Disbarking the Oak. The season for disbarking the oak for the tanner is later than that for disbarking the birch, the larch, the willow, or any other tree the bark of which is sufficiently valuable to be taken off. In most of the trees mentioned, the sap will be found sufficiently in motion towards the end of April: but the oak, relatively to these trees, will always be found a month later. As the mode of performing the operation, and managing the bark afterwards, till it is sold to the tanner, is the same in all trees, we shall defer giving it till we treat on the subject of arboriculture generally.
Accidents, Diseases, Insects, Epiphytes, &c. The British oak is not subject either to many accidents, or to many diseases; but, like every other plant, it has its parasitical and epiphytical vegetation; and it is infested by numerous insects.
Accidents. Oaks are said to be more frequently struck by lightning than