2IO TRANSACTIONS OF ROYAL SCOITISH ARBORICL'LTURAL SOCIETY. 



managing in such a manner as to encourage the trees to develop 

 a mass of strong roots, together with strong side branches, 

 forming a close barrier to the wind. If this matter was properly 

 attended to destruction by gales would be reduced to a 

 minimum. 



Notwithstanding the large amount of damage done by recent 

 gales and the large amount of timber suddenly thrown on the 

 market, the demand and prices for timber, especially converted 

 timber of all kinds, is on the increase, which alone should 

 give encouragement to afforest all available waste ground. 



26. The Use of Explosives in Forestry. 



By Dr Alexander Lauder. 



The use of explosives for removing tree-stumps from the 

 ground has been common for many years. Recently, however, 

 the more extended use of explosives in connection with clearing 

 the land for planting, root pruning, breaking up the subsoil to 

 improve the drainage, as well as for agricultural purposes, has 

 been recommended. 



Whether the method is capable of this extended application 

 depends not only on its efficiency but on its cost and its safety 

 in the hands of ordinary workmen As far as the latter point 

 is concerned there does not appear to be any danger if 

 ordinary care and intelligence is exercised by those carrying 

 out the work. With regard to cost, the following formula 

 is suggested for calculating the cost of the explosive 

 required to remove tree-stumps. For pine and fir trees the 

 square of the girth in feet divided by 20 gives the approximate 

 cost in shillings of the explosive required, e.g. for a tree 7 feet 



in girth '- — ' = 2s. 6d. approximately would be the cost of the 

 20 



explosive required. For deeply rooted trees, such as the oak or 

 elm, the cost would be about double this. As regards the 

 weight of explosive to be used, this may be calculated from the 

 girth of the tree as follows : — 



Pine stump, 5 feet in girth in light soil ^— ^ =8^ ozs. 



3 



Oak stump, 4 feet in girth in very strong soil - — ^= 16 ozs. 



