Growth of Red Pine in Ontario. 165 



This table exhibits in a striking manner the enormous discrep- 

 ancy that exists between the Doyle, Scribner and International 

 log rules ; especially for the smaller trees. Applied to the 20 per 

 cent, cruise made of the stand, the figures in the table give only 

 10,812 board feet per acre by the Doyle rule; 17,107 by the 

 Scribner; and 23,362 by the International. As the average num- 

 ber of merchantable red pine trees per acre is 138 this figures out 

 to an average per tree of 78 board feet by the Doyle, 123 by the 

 Scribner and 167 by the International. As timber limits in On- 

 tario are generally estimated to have so many million feet of tim- 

 ber per square mile it is of interest to apply our figures to a 

 square mile of red pine similar to that in which our studies were 

 made. According to the Doyle rule it would contain approxi- 

 mately 7 million board feet ; according to the Scribner 1 1 million ; 

 and according to the International 15 million. 



As the stand contains 3,830 cubic feet of wood, inside the bark, 

 per acre it is of some interest to note that the Doyle scale allows 

 only 2.8 board feet as the equivalent of a cubic foot, the Scribner 

 4.5 and the International 6.1 board feet to the cubic foot- Leav- 

 ing out the stumps and unused tops, and thus confining our con- 

 verting factors to the merchantable saw logs, these numbers 

 would be raised to 3, 5 and 7, respectively. 



Height Growth. 



A study of 197 red pine seedlings found in open spots and on 

 adjoining cut-over lands showed that the average height growth 

 during the first fifteen years was as follows: 



Age. Height. Age. Height. 



(Years.) (Feet.) (Years.) (Feet.) 



