NOTES 835 



As pointed out to me by Mr. O'Connor, the "genuine rock" elm can 

 be readily told from "soft" elm by the bark and by the checking of the 

 log ends after felling. The bark is in thicker ridges, which are more 

 pronounced, deeply cut, and continuous than those of soft elm bark. 

 Soft elm logs nearly always show ring shake and little checking, while 

 rock elm logs are rarely shaky, but usually have plenty of radial season 

 checks. This difference is remarkably consistent with the difference in 

 -character of bark. 



The trees apparently dift'er in branching habit. '"Soft elm" charac- 

 -teristically sends up large branches almost vertically from the point 

 where the crown breaks. "Rock elm" does not seem to have this char- 

 acteristic — at least to such a pronounced degree. 



The trees are probably equally tall. The "soft elm" has a more 

 rapid taper, a shorter stem, and a heavier top than "rock elm." "Rock 

 •elm" is most abundant and well developed on high, stony ground ; 

 ^'soft elm" in low places; but some trees of "rock elm" are found on 

 lower situations and some "soft elm" on high, stony ground. When 

 ''soft elm" is found on higher ground, however, it is apt to be short and 

 swell-butted, in contrast to the longer-bodied "rock elm." Mr. O'Con- 

 nor stated it as his belief that "soft elm" becomes swell-butted through 

 the freezing of the large amount of water held in the pores. 



"Rock elm" is straight grained and splits easier than "soft elm." 

 In falling "rock elm" the heart must be almost entirely cut through in 

 notching, or the tree will split clear to the top. This straightness of 

 grain and ease of splitting was demonstrated when the special order of 

 "rock elm" was sawn for the Curtis Company ; heart planks would 

 sometimes split through the center from end to end when dropped 

 from the saw. 



Cruisers apparently have no difficulty in selecting the more typical 

 ■*'rock" and "soft" elms, but they speak of "hybrids" between the two 

 ■which are inferior to "genuine" "rock" elm. In most cases, however, 

 •distinction is plain. It was perfectly easy for Mr. O'Connor to select 

 the trees for the special order of "rock" elm lumber ordered by the 

 Curtis Company. 



The lumber of the two kinds is quite different in appearance. "Soft" 

 ■elm lumber has a slight resemblance to ash, the pores being quite pro- 

 nounced on tangential section. "Rock" elm lumber, on the other hand, 

 has a more even texture, the pores not being so evident. 



While this "rock elm" is probably not Ulmus racernosa. it is very 

 possibly tlu' kiiul from which the specimens of "rock elm from Wiscon- 



