Band and Connecting-Rod
In the case of old trees, or such as are not likely to greatly increase in size, the bands need not be much larger than the actual size of the branches to which they are to be affixed, but where the tree is young and vigorous, room for expansion should be provided. Fixing the bands and connecting-rods is readily accomplished either by the use of ladders or by climbing the trunk and slinging the portions into position by means of ropes. The exigencies of each case will point out the best means of carrying out the work, as also the height at which the supports can most effectively be placed. When damaged or diseased branches are being dealt with, great care is necessary to ensure that the bands are placed in such positions that the greatest leverage against wind is afforded, and so as to minimize the risk of the branch being broken across at the weakened point during stormy weather.
Frequently, where the main trunk divides into two or more portions near ground level, it will be found that a split or crack has been caused by the swaying of the divided stems. In such cases the split between the stems should be carefully cleaned out, treated with an antiseptic and filled with asphalt. The limbs should then be braced together by means of a band and connecting-rod, and, as the asphalt becomes set, the brace may be tightened up as may be found necessary.
Rarely is it found necessary to place a band around the stem of a tree to prevent splitting. Where, however, appearances point to the likelihood of this taking place, as in the case of forked trees, especially when the stem divides abruptly into two or three heavy limbs, it is a wise precaution to encircle the bole with a wide band of iron. This band should be placed at such a height that the greatest possible resistance to splitting of the stem is afforded. Such bands are usually proportionate to the strain of the stem to which they are to act as support. A band of leather or rubber between the iron and bark of the tree to allow for expansion of the stem is necessary.
Supporting tree branches by chains is not to be recommended, for the simple reason that, however carefully they may be adjusted, friction and chafing of the bark and wood is sooner or later bound to ensue. Connecting the flat iron bands, already referred to, by means of chains or strand wire, is, however, not so open to objection nor attended with such ill effects as is the case when the chain or wire is placed in direct contact with the branch, for even with the most careful adjusting and packing, the uneven surface of a chain, with its saw-like action during stormy weather, soon renders the belting useless for the purpose intended, and both bark and wood suffer in consequence.
Occasionally we see holes bored through the live branch or trunk in order to fix the binding rod or chain—a most reprehensible practice that, fortunately, has few supporters amongst those who have even had a cursory knowledge of trees and their growth.
It is, however, generally admitted that there are several disadvantages connected with bracing trees with iron rods that pass through holes bored in the trunk or branch. However carefully this operation may be performed, there are grave risks from insect and fungoid attacks in holes that have been made in living wood, as the friction caused by the movement of the tree renders healing of the wound quite problematical. Further, the movement of an embedded iron rod is not only apt to cause friction with the wood but the strain must often be in an opposite direction to that which was intended, this increasing with the diameter of the stem or branch.
Another untidy, slipshod and most objectionable method of staying a tree is by using wire as a band around the trunk. This certainly has the virtue of cheapness, but in so far as efficiency is concerned, and especially in the case of old trees, it is to be deprecated.
In the repairing and strengthening of tree limbs it should consistently be borne in mind that any girdle or band that either partially or wholly constricts the growth of a branch defeats its own object by preventing the uninterrupted flow of sap and impairing the strength of the limb. With care in forming the band and a proper method of adjusting it, there is no reason why the desired object of strengthening a stem or branch may not be attained. On the other hand, a badly formed, narrow band, too tightly applied and without the requisite packing, may in a short space of time be productive of the most unsatisfactory results, particularly in the case of young and fast-growing trees. The main point is that the bands should be fixed in such a way that friction to the bark is avoided and the flow of sap uninterrupted. Unfortunately in the past this has not in all cases been carefully provided against, with the result that the bands, owing to their being too small, gradually became embedded in the wood and, by injuring the cambium and preventing the flow of sap, defeated the object for which they were intended. For fuller information on doctoring trees, the reader is referred to my book on Tree Wounds and Diseases.