Mar, 25, 1914 



Tyloses in American Woods 



463 



in the sapwood as starches, which undergo a transformation when the 

 heart wood is formed. 



The following tabulation of the "Relative durability of hardwoods," 

 compiled from the results of experiments, indicate that tyloses are a 

 factor in durability. The more durable species will be found, with a 

 few exceptions, to contain many or very abundantly developed tyloses. 

 (See Tables I and II.) 



DURABILITY OF HARDWOODS 1 



Durable. 



Black locust. 

 Catalpa. 

 Osage orange. 

 Mulberry. 



Yellow poplar. 

 Red ash. 



Cotton wood. 

 White elm. 

 Red gum. 

 Hard maple. 

 White ash. 



Red oak. 



Black oak. 

 Red birch. 

 Beech. 

 Hickory. 

 Cucumber. 



Scarlet oak. 



Not durable. 



Black gum. 

 Watergum. 

 Bass wood. 

 Buckeye. 

 Sycamore. 



Cherry. 

 Persimmon. 

 Slippery elm. 

 Bur oak. 



Butternut. 



Gray birch. 

 Paper birch. 

 Aspen. 

 Willow. 



The results of tests on 30,160 fence posts 2 indicated the following 

 untreated hardwoods, in order of their durability, as the most suitable: 

 Osage orange, locust, mulberry, catalpa, certain oak (species not given), 

 and black walnut. The length of life in service varied from 10 to 50 

 years. 



Some observations 3 on the life of untreated hardwood railroad ties 

 further confirm the relation between tyloses and durability. It must 

 be borne in mind, however, that for this type of service hardness has 

 been considered in judging durability. The list of woods, together 

 with their life in years under traffic, is as follows : 



Years of service. 



Species. Years of service. 



Butternut 4 Few. 



Beech Do. 



Black, red, or yellow oak 4 to 5 



Post oak 6to8 



Sassafras 6 to 8 



Chestnut oak 9 



Bur oak 9 



Species. 



Black walnut 9 



Chestnut 5 to 10 



Hickory 7 to 10 



Black locust 7 to 10 



White oak 5 to 12 



Mulberry 6 Many. 



Catalpa Do. 



1 This list is offered to show the comparative durability of some American timbers. It is not presumed 

 to obtain for all conditions. 



2 Crumley, J. J. The relative durability of post timbers. Ohio Agr. Expt. Sta. Bui. 219, p. 605-640, 

 xo pi. 1910. 



8 Tratman, E. E. R. Report on the use of metal railroad ties and on preservative processes and metal 

 tie-plates for wooden ties. U. S. Dept. Agr.. Div. For. Bui. 9, p. 216. 1894. 

 * Life not given. 

 6 Little used. 



