278 ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 



their relative merits according to the opinion of the writers. 

 Their cost is so variable for different localities that it is not 

 considered here. 



Kinds of Wood Used in Silo Construction. 



(a) Redwood is one of the conifers which is generally ac- 

 cepted as having the best lasting qualities of any wood used 

 in silo construction. Redwood trees are very large and the 

 lumber uniform. In buying redwood silos, a very good grade 

 of practically clear and full length staves may be secured. The 

 shrinkage and swelling due to moisture is less than in other 

 woods. This is quite an advantage on account of the shrink- 

 age that occurs when the silo is empty. A stave silo built of 

 this material eleven years ago was recently examined care- 

 fully. Every stave was gone over with a knife and not a soft 

 spot was found anywhere. This examination was especially 

 critical near the foundation. Redwood is the wood principally 

 used for conduits. 



(b) Cypress being similar in quality and characteris- 

 tics to white cedar is well adapted to the construction of silos. 

 Only clear or good sound knotted stock should be used. More 

 cypress than any other kind of wood is used for water tanks 

 in the middle west. 



(c) Oregon fir is an excellent wood for stave silos, as it 

 can be secured in full length staves and is quite clear and uni- 

 form. With reasonable care and a foundation high enough to 

 raise it above moisture, a silo with fir staves should last for a 

 long term of years. 



(d) Tamarack or larch is very similar to the best hard 

 pine, but where equal grades of each are obtainable it is slightly 

 preferable on account of its greater durability. 



(e) White pine, if free from loose or large knots, makes a 

 very good silo. The staves cannot usually be obtained in full 

 length staves for a desirable height of silo. 



(f) Long leaf yellow or hard pine is the strongest and 

 stiffest of all pines and if a choice grade is secured, it makes a 



