Masting creates sex-specific growth patterns in Araucaria araucana tree-rings

HACKET-PAIN, ANDREW; HADAD, M.A.; ROIG, F.A.; ARCO MOLINA J. G

Conferencia; TRACE; 2021

Araucaria araucana is a dioecious evergreen conifer endemic to temperateforests of South America. It is a long-lived species (maximum age > 1000 years), withhigh potential for tree-ring based climate reconstructions. However, the species?dioecious habit (individuals are either male or female) is associated with distinct sexspecificgrowth patterns. This introduces novel challenges in the interpretation of theirtree-ring chronologies. We used a network of 10 chronologies from northwest Patagonia (Argentina) to analyse sex-specific growth patterns in A. Araucana.For the first time, we show that differences in the growth patterns of male and femaletrees resulted from their contrasting responses to mast events (years with highseed production). During mast events, the growth of females was strongly andsignificantly reduced relative to male trees. A growth response of similar magnitude wasfound in male trees in the previous year, corresponding to the year of pollination. Thesex-specific growth responses associated with mast events resulted in a strong anddistinct signal in a RWImale?RWIfemale chronology.Despite masting-related differences, male and female tree-ring chronologies shared astrong common climate signal. Our results indicate that sex-specific tree-ring signalscan be leveraged to isolate mast events in A. araucana chronologies, providing anopportunity to develop multi-century reconstructions of large mast events, andimprove dendroclimatic calibration for this species