UTILIZATIOISr OF ELM. 



puted weight of l-inch lumber, the weight of a cord of wood, and the 

 weight of logs per thousand board feet as scaled by the Doyle and 

 Scribner log rules. In this table the cord is calculated as being 

 composed of 90 cubic feet of solid wood. The weight adopted by 

 the Hardwood Manufacturers' Association of the United States for 

 rough white elm lumber 1 inch thick is 3,200 pounds per thousand 

 board feet. Comparison of this with the figures given in Table 3 

 shows that the association weight is for lumber in a partially air-dry 

 condition. A weight of 3,200 pounds per thousand board feet cor- 

 responds to a moisture content of about 16.4 per cent, and air-dry 

 wood usually varies between 12 and 15 per cent. Similarly, the 

 weight adopted by the same association for rough cork elm lumber 

 is 3,800 pounds per thousand, which is somewhat higher than that 

 given in Table 3. 



In general, cork ehn has higher strength values than white elm, 

 and slippery ehn has values between the two. Both white and 

 shppery elm have lower strength values than white oak (excepting 

 the shock-resisting ability of slippery elm), particularly in com- 

 pression perpendicular to grain and hardness. The values for cork 

 ehn do not vary greatly from those for white oak, except in shock- 

 resisting ability, which is much higher in cork elm. The elms aU 

 rank lower than the hickories in mechanical properties. A good 

 quality of cork-elm wood should, however, make a fairly satisfactory 

 substitute for hickory where these properties are of first consideration, 

 as for long heavy handles, the running-gear parts of light vehicles, 

 eveiiers, etc. 



Elm is a fairly durable wood. The estimated average life of un- 

 treated elm lumber in the United States in situations exposed to the 

 weather is from 6 to 8 years. The durabihty of any individual stick, 

 however, may vary from this figure, depending on the qualit}'' of 

 the wood and the moisture conditions. White ehn is said to be 

 somewhat less durable in contact with the soil than slippery ehn. 

 It is higlily desirable to treat elm where it is to be used in exposed 

 situations. By proper treatment with creosote its life may be 

 lengthened to 20 or more years. 



Table 1. — Properties of ehn looods expressed in comparative terms. 



Property. 



White elm. 



Slippery elm. Cork elm. 



Weight 



Moderately heavy 



Moderate 



Moderately heavy 



Moderate 



Heavy. ' 



Shrinkage 



Moderate. 



Strength 



Moderately strong 



Moderately stiff . ... 



Moderately strong 



Moderately stiff . 



Strong 



Stillness 



Moderately stiff. 



Hardness . 



Moderately hard 



Good... 



Moderately hard 



Good 



Hard 



Slioelv-resisting ability . 



Excellent. 



CleavabiUty 





do 



Poor. 











