journal articleThe Labora I or v ol Tre e-Ring Research of the I 'mversi tv of Arizona lias developed a new source of climatic data in tile rings of properly located trees and a new method of cyclic analysis specially adapted to handling climatic changes. These two features seem to the writer to open a gateway through which perhaps long-range forecasting may advance. The purpose of this paper, therefore, is to give: First , the climatic basis of our tree-ring- records which makes them proper material in the studv of cimate; second, the extent of these records in time and space, and third, a survey of the methods and advantages of our cyclic analysis. It is still too early to give the results of our tests
