100 



CLIMATIC CYCLES AND TREE GROWTH 



of hundred years of sequoia values were "scrambled" and then treated by 

 the same integration method, as shown in figure 43. So we learned that the 

 manner of smoothing eliminates two-year cycles which in turn leaves three- 

 year cycles or eight crests in the curve most numerous (theoretically), seven 



1.00 

 0.90 

 0.80 



A.D. 132-200 

 (155-177) 



A.D. 155-223 

 (178-200) 



A.D. 178-246 

 (201-223) 



A.D. 201-269 



(224-246) 



A.D. 155-269 



J I L 



Mean curve 



J_l L 



O a 4 6 8 10 12 14 16 18 20 22 23 



Fig. 42 — Hellmann cycle in sequoias, A.D. 155 to 246, using 

 "triple lag" method. Note: dotted lines represent the 

 original unsmoothed means. 



crests next and so on. One scrambled curve has five crests, and one has 

 four, showing that some of the fractionizing in the real curve may be acci- 

 dental, especially in isolated cases. In the scrambled curves the same frac- 

 tion does not occur twice in succession; but in the natural curves the same 



