Solar and climate imprint differences in tree ring width from Brazil and Chile

Tree growth rings represent an important natural record of past climate variations and of solar activity effects registered on them. We performed in this study a wavelet analysis of tree ring samples from Chile and Brazil. We obtained an average chronology of about 158 yr from these trees. The 11-yr solar cycle was present during the 1930-1954 interval in tree ring data. The short term periods, around 2-7 yr that were found are most likely associated with ENSO effects. Furthermore, we found significant periods around 22 yr. These periodicities are coincident with the well known Hale solar cycles. Therefore, the present analysis shows evidence of solar activity effects/modulation on climatic conditions that affect tree ring growth in South America. Although we cannot say on the basis of the present analysis if this effect on climate is local, regional or global, these results add evidence to the important role of solar activity on terrestrial climate over the past ∼150yr.