252 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



of multiplicity" whereas the Arizona cypresses have a high factor, 

 both in their way testifying to the conditions existing in the extreme 

 lower forest-border region. 



Although the figures of table 175 could be made more precise, they 

 are significant, and they indicate the "factor of multiplicity" for the 

 region. Only extended measurement and observation can reveal the 

 "factor of multiplicity." 



A summary of extremes of multiplicity may be brought together, 

 (i) Multiplicity exists. (2) All classes and types of growth layers are 



Table 175. — Average number of diameter and tip flushes per year per species 



DF TF 



CCCb 3 



CMJ 3-9 



Con P 2 1 



Con T 2.1 1.6 



SA I.7S 



TTAp 2.75 1.5 



TTC 3.03 



TTJ 1.7 



TTP 1.8 1.0S 



TTS 3.5 I 



WAp 1.5 I.2S 



WCh 3.2 2.4 



WPe 2 2.4 



W (summary) 2.1 1.9 



XSC 3.96 



XSP 1.95 



YCt 4-3 to 5.2 0.7 (?) 



involved. (3) The nature of the contact, sharp or diffuse, does not 

 determine the outer boundary of an annual increment. On occasion, a 

 portion of the outer border of an annual increment is diffuse. (4) 

 Different radii give different growth-layer counts. Hence, a whole 

 section is necessary to obtain the true number and true pattern of 

 growth layers at any one level. (5) A "factor of multiplicity" exists 

 for the lower forest border, and must also exist, even though zero, for 

 each tree and every region. (6) Chronological and ecological exact- 

 ness demand that we make extended measurement and observation in 

 order to obtain the "factor of multiplicity" for any region. (7) Actu- 

 ally, growth layers are the more or less easily visible expressions of 

 growth flushes whose complete record of complex variations is the 

 most highly prized of information but whose activity is difificult to 

 trace. 



