TREK DOCTOUIXG. 271 



ONE WAY TO FILL HOLES. 



When the wedges were driven in, and their ends sawed off flush with 

 the outside, the entire surface of the cavity was coated with a strong anti- 

 septic, either corrosive sublimate solution or Carbolineura. This latter 

 antiseptic was considered the better of the two, as it is more penetrating, 

 and is less soluble in water than the corrosive sublimate. Then after the 

 cavity had dried a little from its antiseptic bath, it was filled with cement. 



Now to fill a cavity with cement is an easy job, but the way the aver- 

 age man fills a hole in a tree with cement always reminds me of the filling 

 I put in that old Transcendant tree. There is a trick about filling a hollow 

 tree in such a way that the cement will not crack to pieces, and perhaps 

 be pushed out from the wood so that the water and fungi can find en- 

 trance. But the filling does not break when it is put in in the Davey way. 

 Mr. Davey learned years ago, that there was only one way to do the work 

 and keep the cement from falling out, and also to keep water from gaining 

 entrance to the fillefl cavity. This is done by a little V-shaped groove 

 made just inside the margin of the wood and extending entirely around it. 

 This is so important a feature that it is really the key to the situation, and 

 for the purpose of protecting his discovery, Mr. Davey obtained a patent 

 on the process. 



But to return to the way these Davey experts filled the cavities with 

 cement. Small holes were filled solid with cement, and the filling allowed 

 to come just flush with the surface of the wood, and not allowed to ex- 

 tend out on the bark the least bit. To do this, and to be sure the healing 

 callus could not get under the cement, a little strip of bark, possibly half 

 an inch wide, was cut away from the margin of the cavity. This made it 

 easy to bring the cement even with the surface of the wood, and the new 

 bark could heal over the entire filling as easily as if it had been the real 

 wood of the trees. 



REINFORCING. 



When the filling of cement was of large size, extending well up and 

 down the tree, with a large surface exposed, it became necessary to make 

 allowance for the swaying of the tree during heavy winds. If the core of 

 cement extended for a distance of a couple or more feet in length, it 

 would be in danger of cracking, as the tree swayed back and forth in a 

 heavy gale. To prevent this, the cement core was put in jn layers. Sections 

 were made, varying from a few inches high in trunks of small diameter to 

 a foot or more in larger trunks. These sections were reinforced with 

 wires criss-crossed within the cavity, and then separated from each other 

 by a pad of tarred paper. This made joints that could "give" as the tree 

 swayed, and the cement filling be in no danger of breaking. 



It was necessary always to reinforce the cement filling in all of the 

 larger cavities, to give additional strength to the cement. This reinforce- 

 ment was made with galvanized wire, fastened from side to side in the 

 cavity with nails. 



