18 



Neither of the plantations examined was properly spaced, yet the 

 better one has paid a fair profit. To get the best returns a plantation 

 should be set with from 2,000 to 3,000 trees per acre and afterwards 

 pruned and thinned when necessary. Since a large percentage of the 

 trees will not grow straight enough for poles, it will be more profitable 

 to cut the plantation clean when the straighter trees reach post size 

 and thus secure from the sprouts a second crop of posts in less time 

 than was required for the first one. 



BUR OAK. 



The prices assumed for the products of the bur oak plantations are: 

 First-class posts, 8 cents each; wood, $2 per cord. The cost of 

 establishing a plantation is placed at $5 per acre. 



Since the rate of growth shown in Table 9 approximates that of 

 natural bur oak in Illinois, it is safe to assume that this species will 

 succeed on prairie soils throughout the State. But the rate of growth 

 is slow, and in order to produce durable posts the trees must reach a 

 larger size than is necessary for many other species. On the whole, 

 therefore, there is no inducement to plant bur oak on agricultural 

 land unless for wind-breaks or for ornament. 



RUSSIAN MULBERRY. 



Only one small plantation of Russian mulberry was examined. 

 For the value of the products, first-class posts are priced at 8 cents 

 each and second-class posts at 4 cents each. The refuse material is 

 valued at SI per cord for firewood. The cost of establishing a plan- 

 tation is placed at $12 per acre. 



No general conclusions can be drawn from the examination of a 

 single plantation, yet the indications are that Russian mulberry will 

 do well throughout the central part of the State at least. It is certain 

 that a plantation will produce a large number of posts in a compara- 

 tively short time. 



BLACK LOCTJ 



Black locust was extensively planted in the earty days, and for a 

 time it thrived. Then its greatest enemy, the borer, appeared and 

 most of the plantations were cut. In the plantations examined the 

 damage done by borers was extremely variable. In some places the 

 trees were very slightly, if nt all, affected, while in others they had 

 suffered greatly. 



The durability of black locust posts is well known in Illinois, where 

 they sell for a high price. It is not uncommon to find posts sound 

 after twenty years' use. In one instance the posts were still fairly 

 sound after thirty-nine years of use. 



[Cir. 81] 



