The time for- transplanting seedlings is a consideration dependent chiefly upon the thrift which the plants are likely to make in the seed-bed, and upon the dispersion therein; as also upon their kind.

In case of their being sown too thickly, it will then be necessary to give them more room, and for this purpose the healthiest and most vigorous are taken up after the first season and set out in nursery-grounds prepared for their reception.

As the thrift of the many species is so varied, a general direction cannot be here given for all; but usually those kinds with abundance of roots may safely be transplanted in the fall following their sowing, giving at the same time due consideration for their protection against extremes of temperature during winter.

In no wise is it advisable to transplant permanently, or even remove, species which are naturally of sparse root-growth till the spring, as the roots of such are not fully formed in, or hardy enough after, one season's growth to withstand the nipping effects of a winter's frost. Fall planting would be injurious to them, and would probably retard their growth, if not kill them.

With plants of a more mature growth, say of the third season and upward, the fall of the leaf may be taken as a set time to operate upon them (unless the approach of winter be precipitate after this annual occurrence), as the time which intervenes between then and the setting in of frost, in most latitudes, will be sufficient to allow for the settlement of the earth in which the plants are fixed, and to prepare the seedling for an early start in the following spring.

On the transplanting of seedlings of the first season's growth, if any side-shoots exist they should be cut off, leaving only the single stem. As it is particularly requisite to have this member as straight as possible, it should not in any way be interfered with till after it has presented some traits of deportment, after which, if necessary, it may be headed back in accordance with the purpose for which it is intended.

Almost all seedlings require cultivating for a few years after being transplanted from the seed-bed, after which they may be conveyed to situations intended for their permanency.

Previous to transplanting young trees their roots are subjected to a process of pruning, which exercises an important influence on their future thrift; making the wounds, by a course of natural change, throw out an abundance of fibrous rootlets, thereby enlarging the field of nourishment, and establishing an equilibrium of supply and demand so essentially necessary to a vigorous growth. Thi s operation is more confined to plants grown from seed than from cuttings; as in the latter kinds the roots are not long, but numerous and spreading; yet, when convenient, their roots, also, should be released from any superfluous growth by being judiciously trimmed, as any wounds thereby formed do not by any means injure, but in their turn emit rootlets which are formed by the same law that governs the production of similar growth in layers.

Some kinds of trees, as the oak, hickory, and black walnut, produce long, carrot-like roots, which penetrate the soil to some considerable depth, and they are, therefore, an inconvenient species to transplant if allowed to remain in the seed-bed till their roots have fully taken hold; and upon this consideration may be determined the length of time which may be given them previous to removal to permanent sites. In the event of their lengthy existence in the seed-bed their roots may be exposed to injury on being taken up, in which case they are operated on as before described, and all injured parts trimmed off smoothly, no jagged wounds being allowed to remain attached, as these by their liability to early decay retard the thrift of the plant, and, sooner or later, convey disease to that portion of the trunk which they were designed to support and nourish.

Too great attention cannot be given to the subject of root-pruning, as upon this operation depends the after-vigor of the tree. In any event, whether from injury which necessitates it, or on the removal of the plant from the seed-bed, the tap-root should be cut off to one third or so of its length, or at such a length as will conveniently admit of its being placed in an easy position in the soil; this will facilitate, if required, the removal of the tree in after-years, besides tending greatly to its successful thrift.

The following table may be useful to the planter, in showing the number of trees that may be raised on an acre of ground, when set out at any of the under-mentioned distances: