(39) FORMATION AND MANAGEMENT OF PLANTATIONS - SOWING AND PLANTING
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 respect 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 carefully prepare the soil for the trees, removing the weeds afterwards for two or three years till the branches begin to cover the ground; in which state we should leave it during the growth of the plantation, only taking care to remove large weeds. This kind of tree culture, however, can only take place with advantage, on a tolerably level surface, where the soil is of the same nature throughout. Not to speak here of grounds destined for ornamental plantations, the great majority of plantations formed with a view to profit are necessarily on hilly and unculturable surfaces, and where there is probably a variety of soil, even in a limited space. The preparation to be given in such cases is under-draining; for to dig or trench the surface would render it liable to be washed away by heavy rains and thawing snow. Plantations under such circumstances must be formed by digging pits for each tree, and by selecting such kinds as are best adapted to the locality. This frequently occasions the use of a variety of trees in the same plantation, causing a more picturesque effect in the landscape and a more advantageous result in the production of timber. We have already stated that coniferous trees should be transplanted before they are four years old; but that broad-leaved trees may be moved at four, six, eight, or ten years' growth; provided they have been transplanted every two years in the nursery, and that the soil is sufficiently deep and moist to bring the fibrous roots into full action the first summer. when strong plants of this kind are used they overcome the natural herbage immediately; and if carefully planted in good soil, not one in a score will fail. Smaller plants, on the other hand, are apt to be chocked by herbage, and to have their leaves and young shoots injured by insects. In a dry soil and subsoil, plants with a mass of roots cannot subsist the first year; and therefore smaller plants, once transplanted, are preferable. There are circumstances under which sowing is perhaps the only mode of forming plantations that can s be adopted: as for example, in the dunes of Gascony, which by nearly a century of regularly continued sowings have been almost entirely transformed from drifting sandy wastes into forests of the cluster pine. In making plantations of this pine we should prefer sowing several seeds in every place where a plant was intended to remain, unless we could procure a sufficient number of plants of two years old in pots. If more than one came up, the rest should be removed the second or third year; and while the plants are young care must be taken that they are not choked by herbage. When steep rocky cliffs or stony hill-sides are to be covered with wood, sowing is the only mode that can be resorted to; the kinds of seeds to be sown may be selected according to the nature of the debris or the soil in the clefts of the rocks. Where the soil is good, broad-leaved trees may be introduced; where it is poor, the Scotch dir, larch, birch, mountain ash, and white beam tree are most suitable. Where there is no visible soil, two or three seeds, enveloped in a composition of moss, cow-dung, and loam, may be deposited in crevices, or among loose stones; acted upon by the rain, the seeds will vegetate, and find nourishment in the fragments of the ball in which they were enveloped.
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