Dendroclimatology of Araucaria angustifolia: Assessing climatic responses in sites under similar ecological conditions

Dendrochronological studies have increasingly explored tropical and subtropical trees, mainly focusing on their climatic signals. In the neotropics, growth ring width chronologies of Araucaria angustifolia have been developed at several localities in the south of its distribution, in the Atlantic forest biome. However, the signals identified in these studies indicate different patterns of growth response to climate. Understanding the causes of this variability in dendroclimatic signals is important to guide future dendrochronological studies with A. angustifolia. In this work we test the premise that at independent sites, but under similar environmental conditions, chronologies of A. angustifolia exhibit a common growth signal determined by limiting climatic conditions. We developed a new ring width chronology and correlated it with another one already published, both located in Curitibanos municipality, Santa Catarina state, Brazil and with similar climatic, edaphic and vegetational conditions. The chronologies, with reasonable level of internal growth synchrony and sampling effort, showed a common growth signal of moderate magnitude. This common growth pattern between the sites, represented by a regional chronology, showed significant correlations with local climatic variable and with El Niño Southern Oscillation (ENSO), with weak magnitudes. Partial correlations showed that this set of climatic variables was determinant of the common signal between the sites. Our results confirm the validity of the tested premise. Under the conditions studied, the growth response of A. angustifolia to climate is driven by yearly variation in temperature, which operate at different stages of the annual growth cycle and are influenced by ENSO. The low sensitivity of growth to climate is possibly related to the combined influence of multiple climatic factors and/or to moderate growth variability within sites. The multiplicity of climatic factors influencing growth of A. angustifolia trees may also explain some variability of climatic signals reported for with this species.