APPENDIX F CXXIX 



Yield Tables. 



One of the most important matters in the science of forestry is to 

 work out the yield which can be obtained from any tract of timber 

 through a series of years, carefully calculating the cost of protection 

 and administration so as to determine what the final products and 

 profit will be. Studies have been made of a number of the Canadian 

 species although such studies are not sufficiently complete to enable 

 thoroughly reliable yield tables to be worked out. Considerable in- 

 formation of value in regard to the rates of growth of different species 

 and different locations have however been worked out. Considerable 

 of this information was published in a bulletin by Mr. J. R. Dickson on 

 the Riding Mountain Forest Reserve and in a bulletin by Mr. H. R. 

 MacMillan on Conditions in the Crow's Nest Valley of the Rocky 

 Mountains. On the Rocky Mountains Englemann spruce at thirty 

 years of age was found to average 3.8 inches in diameter at breast 

 height, and to be 32 feet in height. At ninety years it was 12 inches 

 in diameter and 86 feet in height, and at one hundred and thirty years 

 it was 15.7 inches in diameter and 102 feet in height. Lodgepole pine 

 at ten years of age was 3 . 2 inches in diameter and 23 feet in height, 

 and at ninety years was 11 inches in diameter and 80 feet in height. 

 Douglas fir at thirty years was 2 . 5 inches in diameter and at one hun- 

 dred and ten years was 12 inches in diameter. In the Riding Mountain 

 Forest Reserve white spruce at thirty years of age was 2.4 inches in 

 diameter and 16 . 5 feet in height; and at ninety years it was 12 . 2 inches 

 in diameter and 64 feet in height. Black spruce at thirty years of age 

 was . 3 inches in diameter and 5 . 6 feet in height. At one hundred years 

 it was 7 . 1 inches in diameter and 42 feet in height. Jack pine (Pinus 

 banksiana) at thirty years of age was 5.4 inches in diameter, and at 

 one hundred years was 12.6 inches in diameter. 



• Fires. 



Fire is the chief influence which interferes with the natural re- 

 production and growth of the forest and it is a very interesting question 

 to investigate what the effect of fire is on the stand of timber. For in- 

 stance, in the Crow's Nest Valley in the Rocky Mountains the original 

 stand of timber was 70% spruce, 25% pine and 5% Douglas fir, but 

 the reproduction which now occupies the ground after recurring fires 

 is 90% pine, 8% spruce and 2% fir. Factors that would affect this 

 change in the compilation of the stand would be the exposure of the soil, 

 the quantity and frequence of the seed crop, and the adaptability of 

 different species for germination under varying conditions. This gives 

 a great advantage to the lodgepole pine on the Rocky Mountains under 

 ordinary conditions. 



