Table 3 . - -Poles classified by direction of grain and spiral ratio classes 



Spiral ratio : 





Direction of 



grain 





class : 



Left 



: Right : 



Left 



: Right 







Number ----- 





Percent ------ 



1: 1-10 



7 







100 







1: 11- 20 



46 



7 



87 



13 



1: 21- 50 



103 



48 



68 



32 



1: 51-100 



73 



42 



63 



37 



1:101-150 



40 



20 



67 



33 



1:151-200 



13 



20 



39 



61 



1:201+^ 



245 



136 



64 



36 



Total 



527 



273 



66 



34 



Poles in this class are practically straight grained. 



Table 4. - -Section of pole in which maximum divergence of grain occurred, 



by pole yard 



Section 









Yard 







: A 



: B 



: C 



: D : 



All yard 



s 







- - - Number - - 





Number 



Percent 



Top 



48 



37 



45 



38 



168 



44 



Middle 



20 



25 



31 



21 



97 



26 



Butt 



27 



29 



22 



35 



113 



30 



Total 



95 



91 



98 



94 



378 



100 



Forty -four percent (168) of the poles exhibited maximum divergence of grain in the top 

 section of the pole. Percentages of the poles exhibiting maximum grain divergence in the middle 

 and butt sections were 26 and 30 percent, respectively. 



Effects of Position on Slope (Altitude) and Stand Density on Spiral Grain of 



Living Trees of Pole Size 



Still another study was made in the summer of 1953 to determine whether spiral grain in 

 living western larch trees of pole size showed any relation either to position on slope or density 

 of stand. Study plots, each consisting of 25 pole-size trees, 6 to 18 inches d.b.h., were es- 

 tablished in dense and open stands on lower, mid, and upper slopes at two locations. One of 

 these locations was the Priest River Experimental Forest within the Kaniksu National Forest 

 in northern Idaho, and the other was near Big Creek Baldy Mountain in the Kootenai National 

 Forest in northwestern Montana. Each tree was measured and described, and slope of grain 

 was measured by means of a bolaxis (16) at 16 feet above groundline on a face where the bark 

 had been peeled away with a drawknife. Table 5 summarizes distribution of the 300 trees 

 measured in this study. 



6 



