Dendrochronological potential of Prumnopitys andina (Podocarpaceae) at the southern limit of its range in the Chilean Andes

Abstract

Prumnopitys andina is a South American podocarp with a restricted distribution in southern Andean temperate forests, and is severely threatened due to habitat loss. Despite much dendrochronological work on other temperate South American conifers, little is known about the dendrochronological potential of P. andina. Here, we examine the main features of P. andina tree rings and evaluate the potential of this species for yielding tree-ring chronologies sensitive to climatic variability. In a population at the southern range limit of the species, we collected tree cores and cross-section samples of P. andina for analyses following standard dendrochronological techniques. 76 tree-ring series from 45 trees were examined, 32 (42%) of which were successfully cross-dated and included in a chronology. We found that the species forms well-defined tree rings with distinct boundaries delimiting annual growth. The chronology began in 1778, with notable periods of suppression and release occurring in the late nineteenth and early twentieth centuries, respectively. The chronology showed a high inter-series correlation value of 0.51, suggesting a strong common signal among trees. December to January precipitation showed a positive relationship with radial growth. Conversely, maximum and mean temperature showed negative relationships with radial growth during the austral summer and autumn. These significant relationships of climate variables with radial growth of P. andina indicate that tree-ring series of this species are suitable for dendroclimatological studies.

Prumnopitys andina is a South American podocarp with a restricted distribution in southern Andean temperate forests, and is severely threatened due to habitat loss. Despite much dendrochronological work on other temperate South American conifers, little is known about the dendrochronological potential of P. andina. Here, we examine the main features of P. andina tree rings and evaluate the potential of this species for yielding tree-ring chronologies sensitive to climatic variability. In a population at the southern range limit of the species, we collected tree cores and cross-section samples of P. andina for analyses following standard dendrochronological techniques. 76 tree-ring series from 45 trees were examined, 32 (42%) of which were successfully cross-dated and included in a chronology. We found that the species forms well-defined tree rings with distinct boundaries delimiting annual growth. The chronology began in 1778, with notable periods of suppression and release occurring in the late nineteenth and early twentieth centuries, respectively. The chronology showed a high inter-series correlation value of 0.51, suggesting a strong common signal among trees. December to January precipitation showed a positive relationship with radial growth. Conversely, maximum and mean temperature showed negative relationships with radial growth during the austral summer and autumn. These significant relationships of climate variables with radial growth of P. andina indicate that tree-ring series of this species are suitable for dendroclimatological studies.