40 CLIMATIC CYCLES AND TREE-GROWTH. 
OLD EUROPEAN TREES. 
It is of course most desirable to carry the tree-records back as far as 
possible for verification of any feature observed in recent years and for 
additional information. But one is met by the rapidly diminishing 
number of specimens and the liability of obtaining records which are 
not representative of the regions on account of the increasing effect of 
individual and accidental variations. It is true that in the very homo- 
geneous region about Flagstaff, Arizona, an average of 5 trees and even 
of 2 gave a valuable record corroborated by comparisons with larger 
numbers; but in these European groups the oldest trees are all from 
the Scandinavian peninsula, and probably the individual trees of 
which I have samples are representative of widely different localities 
in a rugged and mountainous country. Even though not homogeneous, 
the 15 oldest trees have been segregated in 2 groups covering the inter- 
val from 1740 to 1835. 
Group A represents the inner coast of Norway and includes the 
following trees: No. B 3, Os, south of Bergen; No. B 11, Sopteland, 
south of Bergen; No. B 12, Sogne Fjord; No. B 15, Hardanger Fjord; 
No. B 16, Sogne Fjord; No. N 2, latitude 68° 45’. 
41.00 
| -70 
175Q 1800 
Fic. 10.—Growth of old European trees. A, six Norwegian trees, mostly from 
inner fjords. B, eight trees from Dalarne, Sweden. 
Group B is made up of 8 trees from Dalarne, central Sweden, and 
1 from Lapland, latitude 64° 30’. This group, therefore, represents 
somewhat more homogeneous conditions, but yet it can not be well 
summarized in its larger fluctuations. When plotted with Group A, 
as in figure 10, it shows the latter to have a considerable tendency to 
reversal, a characteristic already observed in this region. But there 
are discrepancies in Group B consisting of sudden depressions in growth 
