Solar variability and width of tree ring.

The relationship between solar activity and the global climate is not only an academically interesting problem but also an important subject for human beings. We have found an interesting relation that may be connected with above profound problem. We have analyzed the tree rings that had survived for 391 years in Japan. The tree archive is very important since it includes the period of the Maunder minimum. Quite surprisingly, Fourier analyses of the annual growth rate identified two cycles with periodicities of 12 and 25 years during the Maunder minimum, but no such cycles were found for other time periods. Possible interpretations of this result are presented. [ABSTRACT FROM AUTHOR]