This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
99. This, to speak properly, is the first nailing which is made After the winter pruning. In consists in fastening to the wall, or trellis, all the principal branches of the tree. By this operation we give the Peach tree the regular form that it ought to present, maintaining its branches at proper distances and in a suitable position. The earlier the pruning, the more important it is to train in the branches immediately; because, should a sudden change in the temperature take place, its bad effects are not so much felt by the tree when nailed, and protected by the copings, and by straw mats in the worst aspects. It is absolutely necessary that all the wood-branches should be trained in a perfectly straight line, because the least curve might draw the sap to the shoots that may be there, and give them a disproportionate strength, and thus render them troublesome. Training in the principal branches is of greater importance on this account than on that of its giving a regular appearance to the tree.
Although this operation appears very easy, it is not without its merit when well 'done; and sometimes we can not do it well at the first attempt The intelligent cultivator, who is fond of his calling, never hesitates about going over his work a second time, in order to give it the desired regularity.
100. This training affords an excellent opportunity of restoring the balance of strength between two wings, one of which is stronger than the other; as also between principal branches on the same wing, where the sap does not circulate equally. To attain this end, it is sufficient either to nail the stronger part closely against the wall to hinder its growth, or to give greater liberty to the feeble part; so that, being more freely surrounded with air, the vigorous development of its shoots may be promoted. These two means may be employed separately or combined, according to circumstances. Sometimes we even bring the weak side forward from four to eight inches from the wall, supporting it by props placed for that purpose; and when the equilibrium is restored, it is put back in its place. This method must only be adopted when there is no longer any fear of frost.
101. Again, in training the branches of the Peach tree, we can fasten the weak part more vertically and the strong more horizontally. The sap consequently flows with greater force into the former, and the balance is restored. These two means may be employed at the same time on young trees; but in those which have attained their full growth, it frequently happens that we can not bring the strong part any lower, and in that case our only resource is to train the weak part more upright The use of these various modes ought to cease as boon as a more even distribution of the sap has rendered the respective parts equal.
102. In order to facilitate the operation of training, and to give it the desired regularity, we fix guides on the wall, or trellis, so as to regulate thereby the position of the principal branches. These guides are taken away when the formation is complete, and the branches are then maintained in the place assigned to them.