i6o 

 CLEARING WITH EXPLOSIVES. 



The Value of Explosives in Clearing. 



It will be found that the chief uses to which explosives can be 

 put with economy iii clearing land, are in the removal of stumps, 

 and in so shattering logs or standing trees that they burn more 

 readily. Trees can be blown right out of the ground; but, owing 

 to their greater weight they take more explosive than stumps. 

 I therefore consider it more economical to put sufficient explosive 

 under them to blow the earth out from around the roots, at the same 

 time cracking and breaking the roots and butt of the tree. The 

 cracks will extend from 4 to 15 feet up the trunk of the tree; and 

 after a week's exposure to the air in dry weather, even bad burning 

 timber will then burn readily. I have burnt down trees 7 feet in 

 diameter at the ground in six to twenty four hours having used 5s. 

 worth of explosive on some. These trees would have taken a week 

 to burn down in the ordinary way, that is, digging the earth away 

 from them, and drawing timber around them with horses or bullocks. 



The economy of the method will be realised when I state that 

 I have cleared 12 acres of land at a cost of £3 per acre, whereas 

 an adjoining block of similar land cost me about £6 per acre to clear 

 in the old way. This was on light red volcanic soil, overlying light 

 clayey loam. 



The method cannot be recommended in cases where timbei' burns 

 right out of the ground, leaving no roots. But in this district 1 liave 

 found the saving in cost to vary from 25 to 50 per cent, on the usual 

 methods of grubbing and burning. With practice, much better work 

 can be done at less co^t with explosives. The procedure should be 

 varied to suit difft-rent timbers and different soils; the exercise of 

 a little judgement will be found profitable. 



Sound timber, whether trees, stumps, or logs, will be shattered 

 with better effect than hollow or rotten timber, as it offers more 

 resistance to the explosives. 



Condition of the Soil. 



To obtain best results I find that the ground requires to be fairly 

 dry. If it is very dry, the explosion is not quite so effective ; whilst if 

 it is too wet, the force seems to act too deeply in the earth, instead of 

 near and above the surface. In some districts, I am informed, best 

 results are obtained when the ground is wet ; but that is not my ex- 

 perience and I do not know to what degree it holds good. 



Explosives Recommended. 



For firing, a battery guaranteed to fire five or more shots is 

 absolutely necessary for best results. It is possible to work in small 

 timber with fuse and caps, but the method is not so satisfactory as 

 the use of ir battery. - ■ 



