Page:Encyclopædia Britannica, Ninth Edition, v. 2.djvu/342

Rh 322 AKBOKICULTUKE but in the climate of London it is in most seasons neces sary, and may be effected by mats, straw, or evergreens. For convenience, the seeds are generally sown in beds, a slight excavation being made by drawing some of the earth to the sides ; and in order that the seeds may be evenly deposited on a somewhat firm surface, the bottom of this excavation is lightly rolled. After the seeds are scattered over the beds they are again rolled, and the covering of earth thrown over them. It is found that the rolling of the beds before and after sowing, by bringing the seeds into close contact with the soil, accelerates germination. The more tender pines are sown in pots or flat earthen pans, for the convenience of making them germinate under glass, and to facilitate future transplantation; but the pro cess of sowing is exactly the same. The seedlings require nothing but tho usual culture of the nursery for two summers ; after which they should be transplanted where they are finally to remain ; or they should be planted in the nursery in lines, or scattered over beds ; in either case they should be 3 to 6 inches apart, according to their height and the length of the leaves. For the Scotch pine and spruce fir, which grow slowly when young, 3 inches are sufficient ; for the larch, which grows rapidly, and for the pinaster, which has long leaves, 6 inches are required. Here the plants may remain two years, and afterwards be again transplanted; unless they are in the meantime removed to where they are to remain, which, to ensure good timber trees, should be done before young conifers exceed four years growth. Trees bearing Nuts, Acorns, Masts, Keys, &c. These ripen from October to December. Acorns usually in November; but the beech, horse chestnut, walnut, and hazel, ripen their fruit in October, and most of the syca mores and maples in September. All these ought to be gathered as soon as ripe, because the best are liable to be picked up by wild animals as soon as they drop. They may be sown immediately or kept till February, as in neither case will they come up till April or May. The seeds should be sown in a sandy loam, in drills, at such a distance from each other that the leaves of the seedlings may not touch at the end af the first season ; they should be gently pressed down into the soil, and covered to twice the depth of the seed. Drills are recommended for this description of tree-seeds that a spade may be inserted obliquely between the rows, so as to cut the tap-root of the plants, and force it to throw out lateral roots. This is commonly done in the spring of the second year, and, by increasing the lateral roots and their fibres, renders the tree better adapted for transplanting. At the end of the second year plants so treated may be taken up, and either planted where they are to remain, or transplanted into nursery lines, at distances suited to the habit of the species. Here they may remain two years longer, and be again replanted. The larger and stronger broad-leaved tap-rooted trees are, up to a certain point, before they are removed from the nursery, the more vigorously will they grow where they are finally to remain. The size to be attained in the nursery must depend on the condition of the soil into which they are to be transplanted. If moisture be so abundant as to supply the fibrils with water during the first summer, even if the removed plant has a stem an inch in diameter, so much the better ; it being understood that it has been transplanted in the nursery every two years, and is therefore well supplied with fibrous roots, and_ has its wood perfectly ripe. If, on the other hand, the soil into which the plant is to be transplanted is dry and poor, the plants should be removed there at the end of the second year, because such plants, being of small size, have few leaves to exhale moisture, and before they grow large they will liave adjusted their roots and annual growths to the locality. Trees with Cottony, Feathery, and other soft Seeds. The seeds of the genera Populus, Salix, Alnus, Betula, Ulmus, &c., ripen from May to November ; poplars in May ; wil lows and elms in June; alders in November; and birches in October. The seeds of the alder and birch may be kept in a cool, dry, airy situation till spring, or sown immediately after they are gathered. They come up in the May or June following; but the seeds of the elm, poplar, and willow should be sown immediately. Many will come up the same autumn, and the remainder the following April and May. The seeds may be dried and preserved in bags for a year ; but in this case the greater part will not vegetate. Poplar and willow seeds require to be sown on a surface rendered level and slightly firm by rolling. After the seeds are equally distributed over it, they should be covered with light sandy soil, or vegetable mould, no thicker than barely to conceal the seed. After this the bed should be watered and shaded and kept uniformly moist by occasional watering when the plants make their appearance. Of all seedling trees raised in British nur series, none grow with so much vigour the first year as the common elm; and, therefore, the seeds of this tree require to be placed at a greater distance from each other than those of any other kind. The seeds of the elm keep better till the following spring than those of the poplar and willow. Trees with Fleshy Fruits. The fruit of the genera Pyrus, Cotoneaster, Viburnum, Cratcegus, Ilex, Prunus, Cerasus, Rhamnus, &c., ripens from August to December. It should be gathered when ripe, mixed with sand, and laid in a heap till the pulp rots away. With some species the seed may be sifted from the sand and sown in the following February, the seedlings being treated as the seedlings of the conifers. In others the heap may be left for two years, and many of the seeds will not germinate till the third spring. Trees ivith Leguminous Seeds. These include the genera Cytisus, Acacia, Robinia, Gleditschia, Caragana, &c. The pods generally ripen in September or October, but some not till November or December. The seeds may be kept in the pods till February, and then sown in beds, as described. At the end of two years the young trees may be trans planted. THE FORMATION AND MANAGEMENT OF PLANTATIONS. Whether plantations of forest trees should be sown or planted, is a question which has been much discussed. It is readily allowed, that sowing is the natural mode ; but man tries by art to supplement nature, and to obtain a higher rate of production by skill and labour. Some indeed have asserted that the timber of transplanted trees is never so valuable as that of sown ones, the reason alleged being, that the transplanted trees have lost their tap-roots. On examining the roots of full-grown trees, however, no tap root is ever found ; on the contrary, those roots which proceed either directly or obliquely downwards from the base of the trunk, are uniformly much smaller than those which proceed horizontally, a few inches below the surface of the ground. The tap-root, therefore, is chiefly of use to the tree whilst young, and is larger in proportion to the part of plant above ground, in the first year, than in any succeeding year; and as the top of the tree and the lateral roots increase in size, the tap-root ceases to increase, till in ten or twelve years growth, it is found to be the smallest of the main roots of the tree. We assume, therefore, that a transplanted tree, other circumstances being the same, is in all respects as good as a seedling. Hence we conclude, that all artificial plantations ought, in the first place, to be made by planting, and at regular distances. We would