FACTORS OF FOREST PRODUCTION. 125 



the yield doubled in 50 years to 70 cubic feet for 

 the average acre. 



The third factor of production, capital, must, as 

 usually, be divided into the current or working fund 

 which expresses the capital required to carry on the 

 current business, and the fixed investment, which ex- 

 presses the capital tied up permanently as a basis 

 for continuous production. 



Since the labor expense is relatively small, since 

 none or only simple machinery is necessary, and 

 simple tools and no buildings are required to house 

 the crop, and even the procurement of seed and 

 plants may be often dispensed with, the current 

 working fund in the forestry business may be 

 rather small. WhDe, according to statistics gathered 

 by the United States Department of Agriculture 

 in 1893, the current expenditure for wheat and 

 corn crops was ;^8.88 and ;^8.6^ respectively, 

 not counting rent for land and superintendence; 

 in German forest administrations the cost of man- 

 agement to be paid from a working fund averages 

 about $2 per acre, being, for the single items, from 

 22 to 65 cents per acre for protection and adminis- 

 tration, 30 cents to $1 for harvest, 15 to 22 cents 

 for planting and cultural measures generally, 6 to 

 33 cents for road building, most of which might 

 correctly be charged to investment. 



In the logging business, which deals only or 

 mainly with exploitable timber, lacking or not tak- 

 ing into consideration the younger age classes, the 



