Of British trees, timbers are formed of oak, Spanish chestnut, larch, red-wood pine, red-wood willow (the stags-head ozier, Salix fragilis), and sometimes the broad-leafed elm (Ulmus montana) under water.
In Britain, crooked oak for timbers is found chiefly in hedge-rows and open forests, where the winds, casual injury, or overhanging superior branches, have thrown the tree, while young, from its natural balance; or, by the tree, from open situation, or excision of lower branches, parting early into several leaders, which, in receding from each other, form curves and angular bends. On the Continent of Europe, in the natural forest, it is chiefly the tops of old lofty trees which afford the crooks; in consequence, those we import are, for the most part, of a free, light, insufficient quality[9]. {22}
To procure a sufficiency of excellent crooks, every person who has the charge of young plantations of timber intended for naval purposes, ought, in the more exposed situations not favourable to the growth of plank timber, or timber for bending, when the plants are from 3 to 15 feet high, to mark out the most healthy, suitably formed plants, sufficiently close to fill the ground when of the proper size, say 6 yards apart, and to bend these, as the under figures will illustrate. The dotted portion is the growth after being bent. {23}
The bend of floors requiring to be at the middle, and of angular bend, see [Fig. f], young trees of one-half the required length, should have the earth removed from the bulb of the root, from one or both sides, according to circumstances, and the tree and stool partially upset to windward, that is, generally south-west; (the operator, in effecting this, may be assisted by a strong pronged instrument); then fixed in this inclined position, and the earth filled in. This inclination may be given at planting, when the plants are tall.
The best mode of securing the larger plants in their bent position, is by rods, forked or hooked at one end, the other end nailed to a ground-stake;—the upper end, if forked, firmly tied to the bent plant by mat or straw rope. Smaller plants may be secured to the notched tops of stakes by ligatures; and the smallest, particularly larch, pinned down by small stakes with hooked tops. Advantage may also be taken of an adjacent tree of small value, and which would ultimately be required to be thinned out, to tie the bended standard down to the most convenient part of its top or stem, lopping off all above the ligature, if it interfere with the standard, and barking it near the ground, to prevent much future growth. When the workmen comprehend {24} the required bends, they will fall upon methods of fixing the plants in the most suitable position, better adapted to the locality than any directions can teach. The plants will require to be fixed down at least two years, and bent a little more than what is requisite, as in their after-growth they have generally a tendency to become straighter, from depositing the thickest layers in the hollow of the bend. A fine regular curve may be obtained by bending the plant for several successive years, a little lower every year; this gradual lowering does not so much check the growth of the leader, nor tend so much to cause the feeders upon the upper side to push as leaders. When oaks are bent, great attention must be paid to cut away any ground-shoots, and to cut off or twist down any strong feeders that stand perpendicular on the upper side of the tree; and also for several years afterwards, to look over the trees twice a-year, correcting any exuberant feeder, and destroying root-shoots. The forester ought to keep in mind that his pupils are proverbially pliant, and that, should his growing timber not be of the most valuable and most appropriate figure, he must rank either with the negligent or the incapable.
Ship timbers being generally required of greater depth than thickness, that is, broadest in the plane {25} of the curve, hedge-row is better adapted to growing them than the forest, especially when the trees are close in the row. The bend generally takes place across the row; and the bole of the tree acquires a greater diameter in that direction than in the line of the row. If the figure of the top of a tree be very elliptical in the horizontal plane, the cross section of the bole, instead of being circular, will also be elliptical (cake-grown). The lateral spread of the roots in thick planted rows being greater than the longitudinal, also tends to give elliptic bole, the stem swelling most on the sides where the strongest roots enter, which, of course, always occurs on the sides affording most nourishment. Forests intended for ship timbers might be planted and kept in rows a considerable distance apart, with the plants close in the row, and thus acquire the elliptic bole. This would also facilitate the bending; by being turned a little right and left alternately, they would spontaneously, from the weight of the top, and their inclination to avoid the shade of each other, increase the original bias. Were forests planted in close double rows, the plants thick in the row, with wide avenues or glades between, many of the trees would acquire crooked boles, and the crooked might be retained when thinning. Avenues of this description {26} would form agreeable diversity from the monotonous irregularity of the forest, and be highly picturesque.
Were close triple rows planted with wide glades between, having spruce, larch, birch, or other trees of more rapid growth than the oak in the mid row, and oak in the side rows, the greater part of the oak would be thrown out into fine curves by the overshadowing top of the superior tree. After the oak had received a sufficient side bias, the central row, which of those kinds comes soon to be of value, might be removed.
The easiest way to procure good oak knees is to look out in hedge-row and open forest for plants which divide into two or four leaders, from 3 to 10 feet 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; see following figures. Figs. a, b, f, are drawn to a smaller scale than c, d; of course, a stem, after dividing, never extends in length below the division.
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