FORESTRY. 211 



753. If the supply of posts was obtained by cutting 

 locust trees which would make two posts each, and were 

 planted 8 by 12 feet apart, how much land would have 

 to be cut ov-er ? 



754. The ordinary life of a chestnut telephone pole is 

 12 years. If the poles are treated with a preserving fluid, 

 they will last 10 years longer. The average cost of an 

 untreated pole is $5.04 and of a treated pole $5.72. If 

 treated poles are used, what will be the saving in 25 years 

 per mile, 40 posts being used for each mile? 



755. A farmer wishes to build a fence one-half mile 

 long, with the posts 16^2 feet apart. If he used un- 

 treated posts at a cost of 15 cents each, he would have to 

 renew them after eight years ; if he used those which had 

 been preserved against decay at a cost of 6 cents per post, 

 he would not have to renew his fence for 16 years. The 

 cost of setting the posts in either case is 5 cents each. 

 What would he save by using the treated instead of the 

 untreated posts? 



756. A farmer owns 200 acres of loblolly pine, which, 

 if cut now, would yield 10,000 board feet of lumber an 

 acre worth $2 per thousand feet. If in 5 years the price 

 of loblolly pine will be $3 per thousand feet, and if the 

 cost of taxes and protection is 2 cents per acre per an- 

 num, what rate of simple interest would the farmer real- 

 ize if he held his timber instead of cutting it ? 



757. A cattle raiser owns three adjoining sections of 

 land, which he has to keep fenced with wire fence in 

 which the posts are set two rods apart. The posts now 

 set are expected to last 15 years, but the owner wants to 

 provide for renewals. He knows that by planting cedar 

 6 by 6 feet he can get a quantity of single post trees in 

 from 15 to 20 years, and by thinning the stand to 12 by 



