THE GARDENERS' CHRONICLE OF AMERICA. 



13 



popular interest in the treatment of decayed places in old 

 ■trees. This t,vpe of work can be regarded as comprising 

 .three essential operations : ( 1 ) Removing all decayed 

 and diseased matter, (2) sterilizing and vvaterprooting 

 all cut surfaces, and (3) filling the cavity in a manner 

 that will favor rapid healing and exclude rot-prdducing 

 ■organisms. 



The necessary tools for digging out decayed matter 

 are few. As a rule, two outside-ground socket-handled 

 gouges (one with a curved cutting edge of about three- 

 fourths of an inch and the other, perhaps, one and one- 

 half inches), a chisel, a mallet, a knife, and an oilstone 

 are sufficient for ordinary w ork. The gouges, chisel, and 

 "knife should never be used near the cambium when they 

 lack a keen edge, as dull tools will injure it. In cutting- 

 out deep cavities, longer interchangeable handles for 

 the gouges may be necessary. 



Usually an old decayed spot may be partially or wholly 

 ■covered by a new growth of wood and bark at the edges 

 and the visible decayed area be small as compared with 

 that which is hidden. In such cases it is usually neces- 

 sary to enlarge the opening with the gouges and mallet in 

 ■order to make sufficient room in which to use the gouges 

 in the interior. This opening should be sufficiently long 

 to reach all the decayed and diseased hcartwood with 

 little or no additional injury to the tree. 



If the decayed and diseased wood extends some dis- 

 tance above or below the external opening, it is a com- 

 mon practice to cut one or more holes above or below 

 the main opening in order to facilitate the removal of the 

 ■diseased wood. This results in one or more bridges of 

 wood and bark spanning the long interior cavity. This 

 practice is of doubtful value, partly because it is often 

 impossible to see whether the diseased wood has been 

 ■entirely removed from the under side of the bridges, but 

 n^ainly because there is a strong tendency in most trees 

 for the bark and sapwood of the bridges to die and decay 

 as a result of severing the sap-conducting tubes both 

 above and below. If the holes are pointed above and 

 below, there is less trouble from this source. .\ prac- 

 tice that permits a more thorough cleaning out of the 

 cavitv is to make a narrow opening, pointed at both ends 

 and sufficiently long to include all the diseased wnod. 

 This often extends some distance above and below the 

 visible discolored area. 



The most important feature of this stage of the work 

 is to remove all the diseased and insect-eaten wood. 

 This excavating must contiiuie on all sides of the cavity 

 until sound, uninfected wood is reached. .^11 discolored 

 or water-soaked heartwood should be removed, as this is 

 "the region in which the rot-producing fungus is nnjst 

 active. 



Another important point to be borne in mind in sha])- 

 ing a cavity that is to be filled is to have the sides under- 

 cut if possible, so as to hold the filling firmly in place. 

 Care must be taken, however, not to have the wood at 

 the edges of the opening verv thin, as this promotes the 

 drying out of the bark and sapwood at these points. 

 Ordinarilv the edges should be at least tliree-fourths of 

 an inch thick : an inch and a half would be better. 



Great care must be exercised in working around the 

 cambium, and all cutting tools must be kept very sharp. 

 The final cutting along the edges of the bark and sap- 

 wood can usually best be made with a very sharp knife. 

 This cutting nuist be followed immediately by a coating 

 of shellac, which shotdd cover the edges of both bark 

 and sapwood. 



Refore cementing a long cavity it is advisable to place 

 through it one or more bolts, so as to hold the wood and 

 cen^ent more firmly in place. A cavity two feet or less 

 in length will not usually require a bolt, but long cavities. 



as a general rule, should be bolted every 18 to 24 inches. 

 Oftentimes a single bolt can be placed so as to support 

 both sides. In certain cavities it may be necessary to 

 place bolts at different angles. In any case a strip of 

 uninjured cambium at least an inch wide should be left 

 between the edge of the cavity and the bolt. On medium- 

 sized trunks, after deciding where the bolts can most 

 efficiently be placed, a very sharp half-inch bit, sufficiently 

 long to reach through the trunk and cavity, can be used 

 to bore the hole for the bolt. On large, heavy trunks a 

 larger bit should be used. Heavy oval or round iron 

 or steel washers, about three times the diameter of the 

 bolt, should be countersunk into the wood by carefully 

 cutting away the bark at both ends of the hole with a 

 sharp gouge or chisel. 



All split cavities must be securely bolted, particularly 

 near the upper part. If the split comes from a crotch, 

 all decayed and diseased wood should be removed from 

 the sjilit and creosote and tar applied, after which it can 

 be bolted just beneath the crotch, so as to close the crack 

 or at least bring the parts back to their normal position 

 in case decayed matter has been excavated from the crack. 

 If the split is a recent one, a washing of creosote only 

 will usually be sufficient before drawing the sides together 

 with bolts. Under certain conditions, particularly in 

 large trees, it may be necessary to use a rope and tackle 

 blocks to pull the limbs together some distance above the 

 crotch, in order to properly close the crack before bolting 

 it 



If the cavity has a comparatively large opening or has 

 little or no undercutting, it is the custom to drive flat- 

 headed wire nails into the wood in the interior in order 

 to hold the cement filling firmly in place. In medium- 

 sized cavities nails two and a half or three inches long 

 are usually driven into the wood for about half their 

 length. 



After the decayed and diseased matter has been com- 

 pletely excavated and the edges of the sapwood and bark 

 shellacked, the next step is to sterilize the interior of the 

 cavity in order that all germs of disease or decav which 

 are present may be killed and that any which may come 

 in. contact with the cut surfaces during subsequent opera- 

 tions may be destroyed. As already stated, creosote ap- 

 pears to be one of the best preparations to use. Every 

 cut part of the wood and bark must be creosoted, and 

 over this a heavy coating of tar or hot asphalt should be 

 applied before the cavity is filled. 



.'\ good grade of Portland cement and clean, sharp 

 sand free from loam ( 1 part of cement to 3 or less of 

 sand) should be used. A quantity of dry cement and 

 sand sufficient to fill the cavity should be thoroughly 

 mixed before the requisite amount of w^ater to make a 

 rather stiff mortar is added and the whole mixture worked 

 to an even consistency. In large cavities fine gravel free 

 from loam is sometimes substituted for the sand. 



For placing the mixtiu'e in the cavity a mason's flat 

 trowel and an ordinary garden trowel witii a curved blade 

 will lie found convenient. .-X. tamping stick, 1 or 2 inches 

 thick and 1 to 3 feet long, according to the size of the 

 cavity, will be needed ; also some rocks and a pail of 

 water if the cavity is a large one. A layer of cement 2 

 or 3 inches deep can now be placed in the bottom of the 

 cavity with the garden trowel and tamped firmly in place.' 

 This operation is repeated until the cement is 8 to 12 

 inches thick. W'et rocks of various sizes may be em- 

 bedded in the cement provided they do not reach within 

 an inch or twii of its outer face. If the mixture is too 

 wet. it will tend to run out of the cavity under the opera- 

 tion of tamping. If too little water has been used, it will 

 not pack down iiromptly. The top of the 8 to 12-inch 

 (Continued on page 20.) 



