Trees intended for plank ought to be reared in close forest, or protected situation, drawn tall and straight, or what is preferable for a part, with a gentle regular bend, technically _sny_, Figs. v and x, (next page). It requires to be of clean solid texture, from 12 to 40 feet in length, and at least 8 inches in diameter at small end, or any greater thickness. For the conveniency of transport, oak plank timber is generally squared or planked where grown, and is cut out from 2 1/2 to 7 inches in thickness, and from 6 to 18 inches in breadth. Plank is needed of such various dimensions, that any oak tree of clean timber, nearly straight one way, and straight, or with a gentle regular bending, the other, may safely be cut into plank, the section to be in the plane of the {6} curve. Figs. v, x, y, z, represent the most advantageous forms of logs for cutting into plank. The dotted lines shew the section of the saw in planking: the straighter the log is in the plane of the saw, it is the more suitable, as the planks bend sufficiently _side_-way by steaming; Fig. v, of considerable bend and taper, where the planks, when cut, have a bend _edge_-way, is the most valuable: this form requires to be very free of knots. In straight planks, Fig. z, cleanness from knots is not such a desideratum. [Illustration: Figs. z, y, of any length—best long; x, from 25 to 35 feet; v, v, from 12 to 24 feet. In the above cut, for distinctness, the saw is drawn entering the butt. In practice it enters the top.] When planks are cut out where grown, they are sawn from the round log immediately after it is {7} felled and barked, which not only prevents injury from drought-cracks, but produces also a considerable saving of timber and labour, as the wood is softer when green; and the centre planks can thus be had much broader than after squaring the log. The outer part of the matured or red wood, which is partly cut away in squaring, is also the cleanest for bending. The sap or not sufficiently matured wood, when left on the side of the plank in the vessel, wherever it is not always soaking in water, is only useful to the shipwright, as it decays in two or three years, and demands an expensive repair. When plank timber is squared, it is for the conveniency of carriage and stowage, and where timber is of little value. Of British trees suited for plank, the most valuable are oak, Spanish chesnut, larch, red wood pine, and sometimes beech[4], elm, plane (_Acer pseudo-platanus_) under water. As no timber decays under water for a considerable length of time, when put in fresh, unless it be devoured by the sea-worm, beech or any other hard tough wood is nearly equally good as oak for outside plank under light water-mark, provided the timber be hastened out of the bush into the vessel, or be kept in pools, either in log or {8} plank, till used, or be planked, and the plank kept dry under cover. One summer on the ground will generally render a beech log in the bark useless.