PRACTICAL TREE SURGERY 727 



decayed and diseased wood should be consistency. hi large cavities fine 



removed from the split and creosote gravel free from loam is sometimes 



and tar applied, after which it can be substituted for the sand, 

 bolted just beneath the crotch, so as to 

 close the crack or at least bring the 



parts back to their normal position in For placing the mixture in the cavity 

 case decayed matter has been exca- a mason's flat trowel and an ordinary 

 vated from the crack. If the split is a garden trowel with a curved blade will 

 recent one, a washing of creosote only be found convenient. A tamping stick, 

 will usually be sufficient before draw- 1 or 2 inches thick and 1 to 3 feet long, 

 ing the sides together with bolts. Un- according to the size of the cavity, will 

 der certain conditions, particularly in be needed; also some rocks and a pail 

 large trees, it may be necessary to use of water if the cavity is a large one. 

 a rope and tackle blocks to pull the A layer of cement 2 or 3 inches deep 

 limbs together some distance above the can now be placed in the bottom of the 

 crotch, in order to properly close the cavity with the garden trowel and 

 crack before bolting it. tamped firmly in place. This opera- 

 If the cavity has a comparatively tion is repeated until the cement is S 

 large opening or has little or no under- to 13 inches thick. Wet rocks of vari- 

 cutting, it is the custom to drive flat- ous sizes may be embedded in the ce- 

 headed wire nails into the wood in the ment provided they do not reach with- 

 interior in order to hold the cement in an inch or two of its outer face. If 

 filling firmly in place. In medium- the mixture is too wet, it will tend to 

 sized cavities nails two and a half or run out of the cavity under the opera- 

 three inches long are usually driven tion of tamping. If too little water has 

 into the wood for about half their been used, it will not pack down 

 length (Plate No. 4, figure 2). promptly. The top of the S to 12-inch 



block of cement is then smoothed with 



TREATING. the fl at trowel -so that it will slant slight- 

 After the decayed and diseased mat- 'ly downward from back to front, in 

 ter has been completely excavated and order to facilitate drainage. Over the 

 the edges of the sapwood and bark top of this cement block a double or 

 shellacked, the next step is to sterilize single sheet of tarred roofing (or thin- 

 the interior of the cavity in order that ner ) paper is placed after it has been 

 all germs of disease or decay which cut so as to fit the cavity. On top of 

 are present may be killed and that any this, another block of cement is built 

 which may come in contact with the as soon as the first block is sufficiently 

 cut surfaces during subsequent opera- hard to stand the weight and tamping 

 dons may be destroyed. As already without forcing any of it out at the bot- 

 stated, creosote appears to be one of torn of the cavity. If the interior of 

 the best preparations to use. Every the cavity extends well above the level 

 cut part of the wood and bark must be of the external opening, it may occasion- 

 creosoted, and over this a heavy coating & Uy be necessary to bore or cut a down- 

 of tar or hot asphalt should be applied ward slanting hole from the outside to 

 before the cavity is filled. the top of the interior cavity, through 



which a watery mixture of cement may 

 be poured to fill the upper part of the 



A good grade of Portland cement cavity and the hole. The main opening 

 and clean, sharp sand free from loam of the cavity must be completely closed 

 ( 1 part of cement to 3 or less of sand; with the stiffer cement before this wat- 

 should be used. A quantity of dry ery mixture is introduced. \Yhen a 

 cement and sand sufficient to fill the block of the cement has partially hard- 

 cavity should be thoroughly mixed be- ened, it will be necessary to carefully 

 fore the requisite amount of water to smooth the outer surface or cut it down 

 make a rather stiff mortar is added and with the flat trowel to the level of the 

 the whole mixture worked to an even cambium, taking great care that the lat- 



