This page has been validated.
26
CLIMATIC CYCLES AND TREE-GROWTH.
only. A comparison between the 5 and these oldest 2 taken by themselves give an agreement not absolutely perfect, yet so close that errors thus introduced will not materially affect the curves. However, the oldest 2 were very slow-growing trees and they required on the average an increase of about 30 per cent in order to make their curve continuous with the whole 5. Thus the tree-record is made to begin at 1385. In the recent years of the record also, between 1891 and 1896, a slight correction was made for omitted rings, the complete omission of a ring being an exaggeration that introduces error.
Fig. 4.—Comparison of two Flagstaff groups. Variations in annual rainfall according to month of beginning annual means.
