396 PRINCIPLES AND PRACTICE OF PRUNING 



303. When to undertake tree surgery. — As a general rule, tree 

 surgery may he safely undertaken at almost any time of year when 

 the sap is not running too actively and the weather is not cold 

 enough to freeze the cement. In most trees the sap will interfere 

 with the work only from the time the buds begin to expand in the 

 spring until the leaves are full grown. Cement work will be ruined 

 if it is frozen before it is hard. It is not likely to be injured by 

 frost after it has been drying for a week. 



304. Guying. — Closely associated with the work of tree surgery 

 proper, and often an indispensable adjunct, is the guying of limbs 

 to prevent the splitting of the crotches or to check further splitting. 

 The best place to put these guys depends largely upon the shape and 

 position of the limbs to be braced. This varies so widely in different 

 trees that it will be impossible to give very specific directions for 

 this kind of work. 



A simple method of guying a crotch is to place a hook bolt through 

 each limb, with the hooks in the two limbs toward each other and 

 from 3 to 10 feet or more above the crotch (depending upon the 

 size, position and length of the limbs) and slipping the end link of 

 a stout chain over one of the hooks (Fig. 303 C). While at the 

 proper place in the chain to make a sufficiently taut guy a link is 

 slipped over the other hook. The rest of the chain may then be cut 

 away if desired (Fig. 309 A). 



Modifications of this method may be used where three or more 

 adjoining limbs are to be guyed collectively. A simple method is 

 to place a hook bolt through each limb at the proper place and then 

 hook a link of the chain over each bolt hook at any desired point, 

 one of the hooks serving to hold the two end links of the chain. 

 The precautions mentioned under "Bolting" (296) should always 

 be followed, so far as they apply to boring and tarring the hole and 

 countersinking the washers of the bolts. 



A turnbucklc rod or bolt is much better than a chain when the 

 guy is to be kept perfectly taut at all times. Furthermore, this rod 

 permits a ready tightening of the guy within certain limits should 

 it later become necessary. If for any reason the guy is to be placed 

 within a foot or two of the crotch, a single long bolt may often be 

 used to better advantage (Fig. 309 B), and sometimes a single long 

 bolt may be used in place of a chain or a turnbuckle rod where the 

 guyed limbs are not likely to twist much as they sway in the wind. 



Occasionally it may become necessary to guy a whole tree in 

 order to prevent the breaking of the trunk where an unusually large 

 cavity leaves only a thin shell of sound wood, or to prevent the 

 tree from tipping over. This may be accomplished by attaching 

 four guy chains or ropes to the tree about half way from the ground 

 to the top of the tree and having these slant downward at an angle 

 about er|uidistant around the tree (e. g., on the north, east, south 

 and west sides of the tree). 



The method of attaching the guys securely to the posts is im- 



