320 



FOREST PRODUCTS 



Species. Years. 



Northern white cedar 12-16 



Western red cedar 12-16 



Southern white cedar 11-15 



Chestnut 



White oak . .... 



Cypress 



Longleaf pine 



Loblolly pine 



Redwood 



Western yellow pine. 

 Lodgepole pine . 

 Douglas fir 



8-12 

 7-1 1 



ii-iS 

 6-10 

 4- 6 



12-15 

 2- 4 

 2- 4 

 6-10 



Photograph by E. T. Chapin Co 



Fig. 86. — Method employed in piling and loading poles on cars. 



The life of untreated piling depends upon a number of factors, chief 

 of which are: (i) the kind of wood; (2) size; (3) amount of abrasion and 

 wear and tear to which it is subjected; (4) damage by marine borers 

 (teredo, limnoria, xylotrya, etc.) ; (5) exposure to elements which encour- 

 age decay. Piles retained entirely underneath the surface of water or in 

 the ground will last almost indefinitely. 



