ESSAY ON FUEL PLANTATIONS. 79 



planter, all this is impossible. In calculating the quantity 

 of fuel to be obtained from a fuel reserve, planted up, I have 

 estimated the yield from the tenth to twentieth year at 15 

 tons the acre, though I find that Colonel Beddome, in a 

 Report to Government, only estimated the yield of ordinary 

 scrub jungle at half a ton an acre yearly. Here there is a 

 great discrepancy, but it must be observed in the Report 

 under consideration the jungle in question had not been 

 planted up or conserved in any way, viz., fenced, and cattle 

 and fires kept out, whereas my fuel plantation has been care- 

 fully conserved and planted up for fifteen years. If we con- 

 sider what half a ton means, the estimate appears surprisingly 

 low. Ordinary trees make a cubic foot of wood a year, but 

 allowing for a dry climate and poor soil half a cubic foot 

 a year is a fair average, or say 251bs. and allow only 300 

 trees the acre, this gives us an annual increment of a little 

 more than three tons an acre a year. I think this is nearer 

 the mark, and if we plant up and really conserve the jungle, 

 a yield of 15 tons a year per acre after the trees are ten 

 years old, is not too high. It is understood that the process 

 of cutting out, and renewal by seed-planting, goes on in a 

 uniform manner. 



Calorific poivers of ivood. 



As there is much uncertainty regarding the calorific 

 powers of various kinds of wood, I append a short table 

 showing how woods vary in their value as fuel. 



Beech wood split and dry ... I'O 



Red pine 0'61 



Poplar 050 



White pine 1 72 



Oak wood (Summed ... 1'18 



It may safely be assum^pthat casuarina, Teak and many 

 of our ncacias have a greater calorific power than any in 

 the list here shown, and the difference between beech and 

 poplar proves how necessary it is that a fuel plantation 

 should only consist of the best fuel trees. It is well known 

 to Engineers, that with inferior fuel steam cannot be kept 



