84 



is offset for the state as a whole. The quantity of fence posts required 

 annually for farm-fencing will depend upon the need for replacing de- 

 fective posts. These annual replacements and the ratio they bear to the 

 total number of posts in use is in turn determined by the average length 

 of life of fence posts in the ground. If this is 10 years, one tenth of the 

 number will represent the annual consumption required to keep up the 

 farm-fencing throughout the state. 



To determine the average period of renewals two methods can be 

 applied. One is to compute it from the average duration of service of 

 each class of posts, weighted by the proportion of posts of this class 

 used. The second is to compile data on the actual number of posts re- 

 quired to maintain fences which have been in place long enough to need 

 annual replacements. 



It was impracticable to determine the percentage of posts of each 

 species on the basis of the data gathered ; but by the second method, 

 based on 1800 miles of fence, the average period of service of a post 

 was found to be 934 years. This would indicate an annual require- 

 ment by farmers in the state for renewals, of 20,530,000 posts, taking 

 no account of the quantity used by other consumers. 



In the construction of the original fences on the farms of the state, 

 at least two thirds of the individual owners probably had a source of 

 supply of fence-post material in their own wood-lots, while a large 

 proportion of the remainder could purchase posts from their neighbors 

 at no great distance. These native wood-lots yielded sufficient supplies 

 of the more durable species to satisfy the demand. In the southern por- 

 tion, white oak was the principal source of supply, with mulberry pre- 

 ferred whenever it was present and walnut used extensively when avail- 

 able. The wood-lots of the northwestern counties yielded burr and post 

 oak, superior even to the white oak in durability. Sassafras was made 

 use of as posts when it had come in on old fields and had attained 

 proper sizes. 



But there remained in many of the prairie counties large areas with 

 no timber or post material except at considerable distances. On these 

 farms, hedges of Osage orange were extensively planted in the early 

 days, and small plantations of black locust were set out by many fanners 

 as a source of future post material. Later, about 15 to 20 years ago, 

 hardy catalpa was extensively advertised and planted for the same 

 purpose. 



