The spectator., 1920-12-21

Tree surgery is comparatively sim pie and inexpensive and most persons can, with a little preliminary practice, undertake the simpler types of tree repair work that will prove immense ly profitable in saving. fine trees. A few fundamental principles must be observed to secure permanently good results.
 QD Remove the dead, deeayed, dis eased or injured wood or bark. When on limb this can often be done best by removing the entire limb; on a large limb or on the trunk it may mean at times digging out the decayed
 @ Sterilize all cut surfaces.
 t3) Waterproof all cut surfaces.
 (4) Leave the work in the most fa- vorable condition for rapid healing; this will often mean filling or cover ing deep cavities.
 (5) Watch the work from year to year fer defects and if any appear at- tend to them immediately.
 Removing Large Llmbs.
 large limb rarely should be re- moved by a single saw cut from the upper side, as thls usually strips the bark and wood as it falls. A prelim- mary cut should be made from the un der side, beyond the point for the final cut; and second cut on the up per side an inch or more beyond the first one. Then cut the stub close to the trunk. A coat of good shellac should he applied over the entire area of the bark, outer sapwood, and the cambium immediately.
 Creosote should be applied to the rest of the exposed wood not already covered by the shellac as protec- ton, and the entire shelacked and creosoted surface should be finally wa terpr0ofed with thick coal tar or as- phalt. Grating wax. particularly the thick liquid alcoholic kind, is excel lent for waterprOofing small surfaces. Another good method of treating the scars Is to char the surface with a gasoline or alcohol blast torch and then quickly cover the hot surface with heavy tar. pitch. or hot asphalt. The treated surfaces should be watched from year to year and recoat- ed as necessary to preserve the wa terproofing.
 In removing small branches and twigs the cut should be made as close to the supporting branch as possible so as to leave no projecting stub. The fruning wound must be sterilized and water-proofed. For very small wounds shellac Is handy.
 When a wound has been allowed to remain untreated for year or more, decay-producing organisms are almost certain to have started an area of de- cay and insect activity behind the ex- posed surface, Such regions gen. ,rally require excavation of decayed and diseased wood and sterilizing and waterproofing of the cut surfaces.
 The tools ordinarily required are two outside-ground socket-handled gouges Gone three-fourlhs of an inch and the other 1la inches), a knife, mallet or hammer. and an oil stone. Only keen edges should be used on the bark or near the cam blum.
 Remove Diseased Wood.
 Remove all the discased or insect eaten or water-soaked wood. In dis eased areas of many years standing hAr hn nf healthy wood around the cavity, in which case the tree must be braced or guyed. and II Is often better re- moved and replaced by healthy one
 Do not leave cavity so 1t will re- tain water. In shaping cavity that is to he filled with cement, etc, have the sides undercut, if possible, so as to hold the filling more firmly in place. Inrolled bark at the edges of the open Ing should be cut away after the de- cayed and diseased matter has been completely cxcavated and the edges of the sapwood and bark adjoining the cambium shellacked. The reIainder of the cavity also must be sterilized. Creosote is recommended. Over this . heavy waterproof covering should be applied.
 Filling the cavity Is of much less im- pOrtance. Often cavity Is better left unified. A cavity must be watched from year to year and any tendency of the waterprooGng to crack, split. or blister should immediately be .oun- teracted by repainting.
 Where sheet metal covering Is used there should be narrow half-inch ledge of bare wood around the edge fc which the margin of the metal can be hacked. The cavity must be thor nughly sterilized and waterproofed.