Small branches along the stem should be left till they approach the dimensions by which the removal of the others is regulated. These principles should be followed up till the required height of stem is attained ; after which the branches composing the top shall be allowed full freedom, in order to increase, by their organising power, the dia meter of the stem.
Coniferous trees require little pruning ; nor is it necessary to com mence so early with them as in the case of other kinds. In dense forests they are found with straight stems approaching the height of 100 feet clear of side branches, the latter gradually decaying below as they become excluded from light and moisture by those above them. When from this cause the lower branches of coniferous trees are observed to lose in a great measure their vigour, and when their foliage contributes little to the enlargement of the stem, they may then be very properly cut off, without waiting for their actual decay. It is a question whether the branches of these trees should be cut close to the stem at once, in pruning; or whether they should first be snagged, that is, cut at some distance from the stem, and either allowed so to remain or be afterwards cut close. That plan is best to adopt by which the least exudation of resinous substance is occasioned, and the blemish soonest overgrown. With the view of preventing the former, the branch may be shortened only to the first live twigs, so as almost to nullify its connection with the stem, preparatory to its final and close removal in the following season.
By choosing the proper season, and by -previous shortening, large limbs of any healthy tree may be closely amputated so as to heal over without affecting the tree generally, or even the portion of stem more immediately connected with the limb to any material extent ; yet the new layer of wood will prove, on cutting up the timber, to be only in close contact with the surface of the wound, which will remain dead, and with which the living matter enclosing it could not coalesce. A
piece of unsound wood is thus embodied. In this case it would be advisable to shorten the limb to such of its laterals as will just be sufficient to keep it alive till the tree is felled. If, in the interval, the branch should push vigorously, means must be adopted to keep it always in a reduced state, by merely allowing as much foliage as will keep the branch alive, without affording any material addition to its diameter.
The proper season for felling trees is when the sap its most at rest. The operation ought not to be performed at any other time, unless for fire-wood. The quantity of sap that may be drawn from some trees is very great. This sap contains the elements of fermentation, the powerful effects of which are evident even on the strong fibre of the oak. Softer woods, although very tough if cut at the proper season, have been observed to crumble almost to powder in a year or two, in consequence of having been cut when in sap.
(Sang's Planter's Kalendar ; Loudon's Arboretum Britaunicum ; Encyclopedlia of Gardening ; Morton's Cyclopcedia of Agriculture; Ste phens Book of the Farm.)