As nothing retards the growth of trees more than full flowering and seeding, if pruning diminish this flowering and seeding, so that the gain from the prevention of this exhaustion more than counterbalances the loss of the pruned-off part, the pruning will of course accelerate the growth of the tree; but the removal of lower branches, although in the first place promotive of growing buds and extension of the top, in a year or two longer only tends to throw the tree more into flowering and seeding. The rich dryness, or want of fluidity of the juices which occasions flower-buds, is also induced by hot, dry atmosphere, and short supply of moisture from the roots during the preceding summer, both of which disposing causes are increased by a long naked stem. When the proportion of the part above ground of a tree to the roots is diminished, growing buds result, at least to a certain extent; yet it would be very difficult to practise a proper system of pruning on this principle, as the consequent lengthened stem is, in the end, promotive of flower-buds, especially in dry seasons, and the loss of feeders might greatly counterbalance the gain from not flowering, did a succession of wet cold seasons follow. {121} The season when pruning should be performed, is something dependent upon the kinds, whether they bleed when pruned in early spring or do not. Almost any convenient time will suit for pruning the latter, but we rather prefer March, April, May, June, or autumn after the leaf has fallen. The former, sycamore, maple, birch, &c. ought either to be pruned in autumn, or after the buds are beginning to break in spring, as they bleed and suffer considerable exhaustion when pruned in the latter part of winter or early spring. From some facts, we consider that pruning in winter, especially in severe weather, gives a check to the vigour of the tree; others agree with this. {122} OBSERVATIONS ON TIMBER.