464 



Journal of Agricultural Research 



Vol. I. No. 6 



A few exceptions are noticeable. Chestnut oak, for example, has 

 very few tyloses, but is hard and strong. Butternut has many tyloses, 

 but it is also much softer than the oaks. Hickory has many tyloses and 

 is here considered as durable a wood as black walnut. This is contrary 

 to observations of its durability by other investigators. The kind of 

 beech used is not specified, but if it was "white-heart" beech tyloses 

 were not present. The "red-heart" beech, which contains tyloses, is 

 often reported as a very durable wood. 



The following recent estimates are based on experience and actual 

 inspection by the Forest-Products Laboratory of woods in service (Table 

 IV): 



TABLE IV. Life of untreated -wood placed subject to decay. 



TYLOSES A FACTOR IN CREOSOTE PENETRATION 

 EXPERIMENTS WITH HARDWOODS 



The study of the effect of structure on the penetration of artificial 

 preservatives, such as creosote, is a separate problem. Preliminary work 

 has shown some interesting results concerning the treatment of certain 

 tylose-filled hardwoods. A piece of air-dry black locust (Robinia pseuda- 

 cacia), 9 by i>^ by i inch, was subjected to a thorough treatment with 

 creosote in a treating cylinder. The piece contained sapwood and heart- 

 wood, the vessels of both of which were filled with tyloses. The stick 

 when split open after treatment showed no penetration except a faint 

 discoloration in the outer one-fourth inch of sap, which apparently did not 

 extend to the tyloses filling the vessels, but was located only in a few 

 scattered groups of fibers. The failure of the wood to absorb creosote 



