GENERAL TREE SURGERY Capital operations in tree surgery are performed with notable success nowadays. When a great limb cracks away from the trunk, threatening the admission of water and disease germs into the cleft, an iron bolt of proper length and strength is pro vided. An auger hole is bored through the limb a foot or two above its base, and another in line with it through the main trunk. Inserting the bolt, through both limb and trunk, the nut is screwed on as tight as possible. This brings the lips of the crack together and holds them. A wise precaution is to wash the wound with some antiseptic, as coal tar or paint, or a mixture of both.
Lightning often tears away part of a tree, exposing the heart wood over an area so large that the tree cannot be expected to heal it. When it is desirable to save the tree, several methods are possible. Thorough painting of the wound is effectual if repeated as the paint wears off. A hollow, as of a limb torn out, may be filled with cement after an antiseptic dressing. The outer bark has to bring its edges together over the cement. A
very successful protection is tar. Sheet iron, tar paper, etc., tacked on over wounds that have not been treated to check invasion of tree diseases, are of doubtful advantage. Outside they look snug and neat, but underneath insects harbour and fungi thrive in the moist darkness which is the most favourable condition for their development. A tree thus protected (?) often goes over in a storm, revealing a rotten heart that has developed since the accident that tore off its limb.
A hollow tree, or one with a cheesy heart, may be opened (if there is no opening on the side), scraped clean of its corrupt interior substance, and filled with cement. With this pillar of stone fitted inside it, the tree is no longer a hollow shell weak enough for wind to overthrow it. Its disease checked, it may take on a new lease of life. Historic trees, especially, justify thorough renovation and bolstering inside; but the average old tree, weakened by accident and disease, is best cut down and a young one given its place.