86 



Average Durabiuty of Species of Wood used fob 

 Fence Posts on Illinois Fakms, untbeated 



Species 



No. of re- 

 plies re- 

 ceived 



Average 

 dura- 

 bility 

 years 



Durability based on 



virhite oak — 10 years 



(U. S. Forest Service) 



years 



Standard 



recommended 



for Illinois 



years 



II. 



Durable 

 Osage orange 

 Mulberry 

 Black locust 

 Catalpa 

 Northern white 



cedar 

 Burr oak 

 Post oak 

 Walnut 

 White oak 

 Sassafras 

 Not durable 

 Elm 

 Black and red 



oak 

 Ash 

 Maple 

 Cottonwood 

 Willow 



25 

 20 

 20 

 15 



15 



11 

 10 



4% 

 4% 

 4% 

 3V, 

 3% 



Required Renewals of Untreated Posts 



40 

 20 

 20 

 15 



15 



12% 

 11 

 11 

 10 

 9 



5 

 5 



4% 

 3% 



3% 



