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.) 
RELATIVE DURABILITY OP HARDWOODS 1 
Durable . 
Black locust. 
Catalpa. 
Osage orange. 
Mulberry. 
Chestnut. 
Black walnut. 
Live oak. 
Sassafras. 
White oak. 
Post oak. 
Black ash. 
Honey locust. 
Cherry. 
Persimmon. 
Slippery elm. 
Bur oak. 
Fairly durable . 
Yellow poplar. 
Red ash. 
Red oak. 
Scarlet oak. 
Butternut. 
Not durable. 
Cottonwood. 
White elm. 
Red gum. 
Hard maple. 
White ash. 
Black oak. 
Red birch. 
Beech. 
Hickory. 
Cucumber. 
Black gum. 
Watergum. 
Basswood. 
Buckeye. 
Sycamore. 
Gray birch. 
Paper birch. 
Aspen. 
Willow. 
The results of tests on 30,160 fence posts 1 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: 
Species. Years of service. 
Butternut. 4 Few. 
Beech.. Do. 
Black, red, or yellow oak. 4 to 5 
Post oak. 6 to 8 
Sassafras. 6 to 8 
Chestnut oak. 9 
Bur oak. 9 
Species. Years of service. 
Black walnut. 9 
Chestnut. 5 to 10 
Hickory. 7 to 10 
Black locust. 7 to 10 
White oak. 5 to 12 
Mulberry. 5 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. 
* Crumley, J. J. The relative durability of post timbers. Ohio Agr. Expt. Sta. Bui. 219, p. 605-640, 
10 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. 
4 Life not given. 
6 Little used. 
