PERIODICAI, LITERATURE 807 



eter selected. It is inaccurate to use a single rate of interest as apply- 

 ing to the rate of yield of a tree or stand throughout its life since the 

 rate varies greatly according to such factors as its age, size, and esti- 

 mated maturity. Thus, by the method just described, assu uing that a 

 tree increases 5 cm. in diameter every ten years and that its diameter at 

 maturity is 40 cm., the future yield in the case of oak is found to vary 

 from 6}4 per cent for trees 15 cm. in diameter to 3 per cent for those 

 35 cm. in diameter. To illustrate the importance of including the loss 

 of future value in reparation calculations, a typical case is cited in 

 which this value amounted to 30 per cent of the value of the high for- 

 est and to 62 per cent of the value of the young reserves. S. T. D. 



Raux, Marcel. Le calctil de la perte de valeur d'avenir et la question des 

 reparations forestieres. Rev. Eaux et Forets, 59:1-10, 1921. 



UTILIZATION, MARKET, AND TECHNOLOGY 



Several species of coniferous woods plentiful 



Western Wood in Idaho, and one species. Port Orford cedar. 



Oils from Oregon, were distilled to determine the 



yields of total oil and the oils were tested for 



flotation value. The table gives the yields of total oil obtained by the 



distillation of the local species. No figures are given for the yields 



from Port Orford cedar. 



Species Yield of oil per 



cord gallons 



White fir 10.6 



Cedar , 11.0 



Larch 12.2 



Douglas fir 13.4 



Lodgepole pine 17.6 



Western yellow pine 55.0 



The high yield in the case of western yellow pine was due to the use 

 of stumpwood instead of cordwood as was the case with the other 

 species. The oils were tested for flotation value on lead and zinc ore 

 and on copper ore, and were divided into three groups depending on 

 their value for flotation work. The first group consists only of Port 

 Orford cedar, the second group contains lodgepole pine, red fir, and 

 larch, which are classed as good flotation agents, while the last group, 

 classed as "fair," contains western red cedar, yellow pine, and white 

 fir. The reviewer does not claim to be a metallurgist, but from the 

 detailed figures of the flotation experiments it does not seem that this 



