70 METHO'DS OF COMMUNICATION FOR FOREST PROTECTION 



Appendix E) which, is elliptical in cross-section not only avoids several of the more 

 serious defects of the original circular and hexagonal types but is much heavier and 

 of better material, and therefore stronger. It will be standard on all Forestry Branch 

 lines. 



3 STRINGING WIRE 



The methods given in Section 57 are also applicable to tree-line construction, al- 

 though the latter offers less opportunity for the use of a wagon. The same precaution 

 should be taken not to injure the wire. In most cases the only practicable way to pull 

 out the wire is by hand from a stationary reel. Where very thick brush is encountered 

 along the right of way it will sometimes require three or four men to pull a half-mile 

 length of No. 9 wire, with an additional man to tend the reel. Two men should take 

 the end of the wire to which a cross-bar is attached for a handle, while the others 

 distribute themselves along the right of way as the strain becomes heavy. It is import- 

 ant to remember to remove the cross-bar from the end of the wire, and to straighten 

 out the latter after having pulled out the coil. 



A large amount of slack -should be provided. The exact amount will be determined 

 by the conditions, topography, etc., but, in general, each span should be given about 

 4 ft. The aim in to provide enough alack so that several trees may fall across the line 

 within a few spans without breaking the main line. 



This should always be tested after the wire is up by catching hold of the line wire 

 between supports and pulling to the ground. It should have sufficient slack to permit 

 this to be done in every, span, and, where slack-holding ties are used, at least four times 

 simultaneously between each pair. 



Under ordinary conditions the use of brackets in tree-line construction should be 

 avoided. 



4 HEIGHT OF WIRE 



The wire should not be hung at a greater height than on a pole line and in general 

 should be hung about 18 ft. above the ground at the point of attachment, giving 14 ft. 

 at centre of span. 



5 SPLIT TREE INSULATOR ATTACHMENT 



The method of making the split tree insulator attachment is shown in Fig. 32. 

 C and D are the insulator attachments that have given the best results. The former 

 uses No. 12 wire and comes loose from the staple whenever a tree falls across the line. 

 In such cases neither the tie wire itself nor the split insulator breaks. To make repairs 

 it is merely necessary to replace the attachment on the staple as illustrated in the 

 figure. 



The attachment D involves the same principle, but uses No. 9 wire. When this is 

 employed it is necessary to keep only one kind of wire in stock, though the tie C is the 

 least expensive and the easiest to make. E shows a little stronger attachment made of 

 No. 12 wire which should be used in conjunction with the crosstie shown at A. All ties 

 should be attached to the tree by means of a 3-in. or 4-in. staple, according to the thick- 

 ness of the bark, about 1 in. of the staple being left protruding from the tree. A 2^-in. 

 post staple may be used in hardwood timber. When there is a possibility that the tree 

 to which the insulator is attached may be cut into sawlogs, a wire wrapped around the 

 tree with a loop twisted in the middle should be used instead of tne staple. 



The staple should be set with its two points in a vertical plane. The split insulator 

 is attached to the line wire by the lineman before climbing the tree. Particular care 

 must be taken in forming the loop of the tie wire around the staple to see that it is 

 snug and that the reversed ends are left about 2 in. long and closely parallel to the 

 shank of the tie. A very great variation in the amount of pull required to detach this 

 tie can be secured by altering the shape of the loop around the staple, and if not pro- 



