An encyclopaedia of agriculture. Comprising the theory and practice of the valuation, transfer, laying out, improvement, and management of landed property ... and the cultivation and economy of the animal and vegetable productions of agriculture, including all the latest improvements; a general history of agriculture in all countries; and a statistical view of its present state, with suggestions for its future progress in the British Isles / by J.C. Loudon.
- Loudon, J. C. (John Claudius), 1783-1843.
- Date:
- 1835
Licence: Public Domain Mark
Credit: An encyclopaedia of agriculture. Comprising the theory and practice of the valuation, transfer, laying out, improvement, and management of landed property ... and the cultivation and economy of the animal and vegetable productions of agriculture, including all the latest improvements; a general history of agriculture in all countries; and a statistical view of its present state, with suggestions for its future progress in the British Isles / by J.C. Loudon. Source: Wellcome Collection.
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![timber of the trunk, though in these cases increased in quantity, is rendered knotty and rotten in quality. 3988. Pruning frondose or resinous trees is one of the greatest errors in the modern system of forest management. The branches of the different species of pines, and of the cedar of Lebanon, never attain a timber size, if growing in a moderately thick plant¬ ation ; those of the fir tribe never under any circumstances. Provided pines and cedars, therefore, are planted moderately thick, no loss in point of timber can ever be sustained by omitting altogether to prune them ; and in this respect the fir tribe, whether thick or thin on the ground, may be left to themselves. The important question is, how does the rotting oft' of the bi'anches aft'ect the timber in the trunk of the tree ? Certainly no pine or fir timber can be sounder or better than that which is brought from the native forests of the north of Europe, and from America, where no pruning is ever given. The rotting oft' of the frondose branches, therefore, cannot be injurious in these countries. The next question is, can it be proved to be injurious in this country ? We are not aware that it has, and do not believe that it can. The rotting off of the branch of a resinous tree is a very dift'erent process from the rotting off of a branch of a ramose-headed tree. This fact may be verified by observing what takes place in pine or fir woods, and by inspecting the interior of foreign pine or fir, cut up into planks. In the rotting oft' of side branches of deciduous trees, we find, that the principal part where decay operates, at least in all the soft woods, and even in the oak when it is young, is the heart; but in the rotting off of the side branches of resinous trees, we shall find them decaying chiefly on the outside, and wearing down the stump of the fallen branch in the form of a cone. On examining the sections of sound foreign deal, we shall find that the knots of the side branches always terminate in cones when the section is made vertically. This is a fact well known to every carpenter; and it is also known to a great many, that British pine and fir timber that has been pruned, has invariably a rotten space at every knot. The same thing is observable to a certain extent in the natural decay of the side branches of all trees. When the decay is natural, it commences at the circumference, and wears down the stump, till it ends in a small hard cone, which is buried in the increasing circumference of the tree, and is never found injurious to the timber ; when the decay is artificial, or in consequence of excessive pruning, that is, suddenly exposing a large section to the action of the atmosphere, the bark protects the circumference, and the decay goes on in the centre, so as to end in forming an inverted cone of rotten matter, which serves as a funnel to conduct moisture to the trunk, and thereby render it rotten also. The conclusion which we draw from these facts is, that the pine and fir tribe should scarcely be pruned at all, and that no branches of ramose trees should be cut off close to the stem of a larger size than what may be healed over in one or at most two seasons. We agree with Cruickshank, therefore, when he says, “ It would appear that the pruning of firs [the pine and fir tribe], supposing it harmless, can yet be pro¬ ductive of no positive good.” 3989. Cruickshank, Pontey, and Sang, agree that the great object of pruning is to protect the leader or main stem or shoot from the rivalship of the side branches, in order that as much of the nourishment drawn from the soil may be employed in the foi'mation of straight timber, and as little in the formation of branches and spray, as is consistent with the economy of vegetation. Without the agency of the leaves, the moisture absorbed from the soil could no more nourish a plant than the food taken into the stomach would nourish an animal without the process of digestion. The branches bearing the leaves are therefore just as necessary to the tvelfare of the tree as the roots. By taking away too many of the branches, only a small part of the fluid imbibed will be elaborated; by leaving the branches too thick and crowded, the leaves may be less perfect, and less fit for performing their office, than they otherwise would be. Exposure of a part of the branches to the light and air may therefore be a sufficient reason for thinning them, independently of increasing the trunk. “ How,” asks Cruickshank, “ are we to know the exact number of branches that may be removed with safety in any given circumstances ? Never, it is answered, displace any which have not already got, or seem in immediate danger of getting, the upper hand of the leader. These will be known by their equalling or approaching the leader in size; or, to speak less ambiguously, by their being of the same, or nearly of the same, girth at the place where they spring from the stem, as the stem itself is at their length from its top.'' In proceeding according to this plan, the primer is not to regard, in the smallest degree, the part of the stem on which a shoot is situated. If it is too large, it must be displaced, should it be in the highest pai't of the tree : if it is not too large, it must remain, though it be close to the ground. “ But how will this method, the reader maybe ready to ask, overproduce a clean stem ? By repeating the pruning, it is answered, as often as the growth of the branches may make the operation necessary. Suppose, the first time a tree undergoes the process, that the branches removed are a considerable distance from the ground, and that there are several smaller ones left growing farther down the stem : these last will gradually increase in size, till they, too, must be lopped off', and thus the stem will be in the end as effectually cleared, though more gradually, and consistently with the health of the tree, as by the absurd method represented above. “ If any branches that were left at a former pruning low on the stem, appear at the next repetition of the process not to have increased in size, we may safely conclude that they have had no influence on the tree either good or bad ; and as it would be in vain to leave them with the hope that they will any longer assist in the elaboration of the sap, they should be removed, as unsightly objects which it is no longer useful to preserve.” {Practical Planter, p. 168.) 3990. Billington considers the leaves and branches of trees as of the greatest importance : he thinks every timber tree ought to have the trunk clothed with branches throughout; but these branches he would shorten in such a way that they should never engross any material part of the timber of the tree. To accomplish this, it is necessary to commence pruning when the trees are young, by which means the great bulk of the timber produced w'ill be deposited in the main stem or trunk. This is what he calls preventive pruning. {Gard. Mag. vol. vi.) A similar system had been recommended by Mr. Blaikiq of](https://iiif.wellcomecollection.org/image/b29304489_0023.jp2/full/800%2C/0/default.jpg)
