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Crotch hollows also come under the heading of wound repair. Many otherwise well-formed trees (particularly yellowwoods) develop deep pockets where their leaders, especially large multiples, branch out from the trunk. In these hollows, which resemble inverted armpits, not only water but fallen bark and wind-blown soil can accumulate. Often parasite plants or seedlings from the tree itself will start growing there. Danger arises from wet-rot and frost pressures. Averting such pockets early in a tree's life or altering them after they have developed is not difficult. The problem involved is purely one of drainage. An open channel can be gouged, or a tube inserted, to the crotch hollow's lowest point. To keep the pocket from collecting debris, fit a sheet-metal cap over it. This can be done also over cavities, to keep out squirrels and such. The tree will accept the shield, with a callus roll, as part of itself if you trace back the bark to open a ledge of wood and tack the metal to it. Crotches forming a wide angle are always stronger than acute-angle or V crotches. Often the latter look strong because they appear to be reinforced by a roll of callus. But that roll was formed, on the outside only, after that crotch was cracked or actually sprung open some time ago by heavy pressure, as of wind or snow, applied to the member aloft. Unlike a metal joint mended by arc welding it is not "stronger than ever" after its healing, but highly prone to refracture in another big blow or snow. It is particularly important to inspect trees near architecture or over driveways for V crotches, callused or otherwise, for they are inherently weak and hazardous. In trees small enough to handle himself, the home owner can reinforce a faulty crotch in one of two ways, or both; rodding and/or cabling. |
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