<, II „,««?«>-» ,, ylft^l E-434 May 1938 United States Department of Agriculture Bureau of Entomology and Plant Quarantine AN EFFICIENT METHOD FOR INTRODUCING LIQUID CHEMICALS INTO LIVING TREES* By A. E. Lantz, Division of Forest Insect Investigations In connection with the project for Dutch elm disease eradication and control it has been found that the presence of large numbers of woodland elms in the infected area seriously hampers the progress of the work. Ex- periments have therefore been conducted to determine how such trees can be treated with chemicals so as to kill them in a satisfactory way and prevent subsequent attack by bark beetles. The prevention of bark beetle attack is important because of the part played by certain species in spreading the fungus that causes the disease. A satisfactory method of applying liquids so that they will be ab- sorbed by elm trees has been devised and is here described. While it has been used only for elm trees, it is believed that it can be used just as satisfactorily for other species. The collar method consists essentially of applying a piece of waterproof material to the tree in such a manner as to form a receptacle capable of holding liquids. With methods previously em- ployed it was necessary to return to the scene of operation to salvage the costly materials used. With the present method the cost is sufficiently low to make salvaging unnecessary, and less skill and fewer tools are required. Rubberized Fabric Collar Rubberized fabric is best suited for the collar material when the dosage is based on a diameter unit. It could be used, however, when dosages are based on a volume unit, provided the dissolving of the chemical used re- quired relatively small quantities of liquid. At this point it might be well to explain that when dosages are based on a diameter unit, the collar width is not changed with the diameter of the tree, but is varied only when the solubility of different chemicals or changes in dosage require it. If dosages are determined by the volume, however, it will be necessary to increase the width of the collar as the tree size is increased. On fairly large trees the increase in material might be prohibitive unless it could be salvaged. 1 The technique described herein is an improvement over that given in E-409, A Method for Preventing Insect Injury to Material Used for Posts. Poles, and Rustic Construction, by F. C. Craighead, R, A. St. George, and B. H. Wilford. - 2 - Tools required . — 1 tree tape, 1 light hammer, 1 hand axe, 1 draw- knife, 1 putty knife, 1 pencil, 1 liquid measure, 1 short 1|— inch chisel (preferably having a composition and steel handle). Material required . — Asphaltum roofing compound, No. 10 tacks, and rubberized sheeting. The sheeting can be purchased in quantities for 25 cents per square yard. Directions for a pplication . — First measure the tree to determine the dosage to be used. Then, using the draw-knife with the beveled side toward the tree, shave off the outer bark. The width of this shaved area will depend on the width of the collar used. Next, using the tree tape as a guide, make a pencil mark around the tree about one-third of the way up from the lower edge of the smoothed area. Then make a kerf along this pencil line by repeated chisel cuts which should cut through from three to four annual rings. Hold the chisel with the beveled side toward the bole of the tree and with the handle pointing upward at an angle of about 45°. The tree at this point will appear as in figure 1. Now tear a strip from the rubberized fabric 1 inch wider than the desired width of the collar. Wrap this strip of material around the smoothed area to get the measurement. Make a suitable allowance (table 1) for pleat- ing, and tear off the material needed. Then tear a 1-inch strip lengthwise from this piece to use later as a band. Start tacking the collar to the tree with the lower edge about f inch below the chisel kerf, making -f-inch pleats every 2 inches around the circumference. The collar should now appear as in figure 2. Next, apply a band of asphaltum compound where the ends of the collar join, and tack this junction to the tree every 1^ inches. Also apply a band of the same material around the base of the collar so that half of it will be over the pleated edge of the collar and half on the tree trunk. This stage is illustrated in figure 3. Now tack one end of the 1-inch strip of rubberized fabric, previously torn off, into the compound along the lower edge of the collar, draw the strip tightly around the tree, press it into the compound, and tack it again. If the surface of the trunk is uneven it may be necessary to put additional tacks at any indentations. The completed collar will appear as in figure 4. Table 2 is given to show the approximate quantity of material that collars of various sizes will hold. These are approximations, since the collars will vary as made by different workmen. They may be made up to 12 inches wide, but collars over 12 inches are inadvisable. It would be pref- erable to refill a narrower collar. Crepe-Paper Collar In a second method which has also been successful, a collar of water- proof crepe paper has been employed. Its use is retricted to comparatively small dosages, but in such cases it is quite desirable, because it can be applied more rapidly than the rubberized-fabric collar and the material is cheaper. - 3 - The material is made in rolls 3 feet wide composed of two thin sheets of paper, with a tar composition between the two, and the assembly is cor- rugated. It is impervious to most chemicals, but some, among them pyridine, acetic acid, and formaldehyde, do attack it. The collar material is prepared before going into the field. This is done by cutting the roll into strips the desired width. One-inch masking tape (this is the cloth type similar to adhesive paper tape) is stuck along one edge by rubbing with a piece of round wood or a roller. These strips are made in rolls of about 50 feet each. M ethod of a pplication . — Prepare the tree as for the rubberized- fabric collar. (See fig. 1.) Next apply a band of asphaltum compound to the tree about -i- inch below the chisel kerf. Then cut the crepe paper material about 1-g- inches longer than the circumference of the shaved area, and pull the corrugations out of the paper by placing the paper between the palm of one hand and the thigh and pulling it through with the other hand. The tape prevents any stretching along the one edge. With the tape on the outside, tack one end of this taped edge into the asphaltum and then, holding the other end of the taped edge, pull it tightly into the compound and tack this end. An occasional tack at any indentations may be necessary to prevent leaks at these points. Join the ends of the collar and seal them in the same manner as with the rubberized- fabric collar. Table 3 gives the approximate capacity of this type of collar. Figure 5 shows the completed collar. Table 1. — Allowance for pleats and lap in collars to be applied to trees of different diameters. Diameter Df tree Allowance for Die ameter of tree Allowance for at breast height pleats and lap at breast he ight pleats and lap Inches Inches Inches Inches 3 4 12 13 4 4 13 14 5 5 14 16 6 6 15 17 7 7 16 18 8 9 17 19 9 10 18 20 10 11 19 12 11 12 - 4 - Table 2. — Quantity of material that can be held by the rubberized- fabric collars of different widths width 1 Capacity per inch of tree diameter 3hes C.c. 5 80 6 100 7 180 .ar width 1 Capacity per inch of tree diameter Inches C.c. 8 230 9 290 iThis is the total width of the collar material. The actual collar will be 1 inch less than this, since a strip is torn off to be used in sealing the bottom of the collar. Table 3. — Quantity of material that can be held by the waterproof crepe- paper collars of different diameters Collar width Capa< Dity per Collar width Capai city per inch of tree inch of tree diameter diameter Inches C.c. Inches C.c. 5 50 9 140 6 80 10 155 7 100 11 166 8 125 12 175 Explanation of Figures Figure 1. — Portion of tree trunk prepared for receiving a collar of either fabric or crepe paper. Figure 2. — The rubberized fabric collar tacked to the tree trunk, showing the pleats in the lower edge of the material. Figure 3. — The asphaltum compound has been applied to the union of the two ends of the collar and over the joint between the pleated edge and the trunk. Figure 4. — The complete collar of rubberized fabric with the 1-inch strip drawn tightly around and pressed into the band of asphaltum. Figure 5. — The completed crepe-paper collar as attached to a tree. SHAVED AREA CHISEL KERF FIG I ASPHALTUM COM FIG 2 ASPHALTUM COMPOUNC II njjiy FIG 3 FIG 4 ^ Digitized by the Internet Archive in 2013 http://archive.org/details/efficientmethodfOOunit Figure 5. — The completed crepe-paper collar as attached to a tree. S,^Te" LANT BOARD UNIVERSITY OF FLORIDA 3 1262 09223 0373