Blasting Stumps 



"Root systems of the different forest trees are subject to a con- 

 siderable number of variations, due to the class of tree, the soil and the 

 depth to sheet water. Ordinarily, forest trees are divided according to 

 their root systems into three classes. These are: Those having tap 

 roots ; those having no tap roots but only lateral fibrous roots ; and those 

 having both a small tap root and many fibrous roots. When trees that 

 normally develop heavy tap roots are grown on soils where the ground 

 water level is very near the surface, the tap root will be materially short- 

 ened or entirely wanting. Fibrous rooted trees growing in loose soils 

 not troubled by bad drainage, may send heavy lateral roots to consid- 

 erable depths. The highly resinous tap roots of such trees as the pine 

 decay very slowly." 



Several factors very material}' influence the blasting of stumps, 

 notable of which are : 



The character of the root, whether tap or fibrous. 



The nature of the soil with regard to the resistance it offers the 

 explosive. 



The state of preservation of the stump, whether sound or partially 

 decayed. 



Freshly cut or green stumps are much harder to blast than those 

 from which the small fibrous roots and bark have decayed. 



Tap rooted stumps are easier to blast than fibrous rooted ones. The 

 semi-tap rooted ones are slightly more difficult to blast than the tap 

 rooted ones, but not so difficult as the fibrous rooted ones. 



In doing successful and economical stump blasting all depends on 

 the proper location of the charge. For stumps of the tap-root variety the 

 best method is to bore into the tap root as shown in Fig. 119. The usual 

 method of doing this is to start a hole with a \ l / 2 -inch punch bar or dirt 

 auger at a distance away from the center of the stump equal to its 

 diameter, inclined at an angle of about 45 degrees towards the center 

 until the tap root is encountered. The earth tool should then be ex- 

 changed for a wood auger and the hole continued to 4 of the way 

 through tap root. Care should be exercised not to bore entirely through 

 this as in that case a good deal of the force of the dynamite when it 

 explodes will be wasted in the soft ground beyond the tap root. The 

 charge to be employed should vary from 1 to 6 cartridges of Red Cross 

 Extra 40% Dynamite, the size of the charge varying in proportion to the 

 size of the stump. Charge should be primed with cap and fuse and firmly 

 packed the tighter the better. Priming, charging and tamping instruc- 

 tions are found on pages 119 to 124. 



If you have a blasting machine and Victor Electric Fuzes and you 

 w r ish to avoid the necessity of boring into tap root, we recommend placing 

 the charges of dynamite firmly against the tap root as in Fig. 120. 

 Charges should be primed with Xo. 6 Victor Electric Fuzes and firmly 

 tamped. The electrical blasting methods are fully explained on pages 

 125 and 126. 



127 



