IANIGLA   20881
INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
artículos
Título:
Removal of a non-climatically induced seven-year cycle from Nothofagus pumilio tree-ring width chronologies from Tierra del Fuego, Argentina for their use in climate reconstructions
Autor/es:
F ROIG; G MARTÍNEZ PASTUR; MATSKOVSKY, VLADIMIR
Revista:
Dendrochronologia
Editorial:
ELSEVIER GMBH, URBAN & FISCHER VERLAG
Referencias:
Lugar: ALEMANIA; Año: 2019 vol. 57 p. 125610 - 125610
ISSN:
1125-7865
Resumen:
A pronounced seven-year cycle is one of the most prominent features of many Fuegian and southern PatagonianNothofagus pumilio tree-ring width chronologies. However, the source of this variability is still unclear. Here weprovide multiple lines of evidence that suggest this phenomenon comes from non-climatically induced ecologicalfactors, most probably triggered by insect outbreaks. To test this hypothesis we removed the seven-year cycle, bymeans of Singular Spectrum Analysis, from a network of 44 tree-ring width chronologies, from the eastern Tierradel Fuego Island in Argentina. The chronologies that were filtered this way showed a stronger climatic response,and were more successfully modeled using the Vaganov-Shashkin-Lite (VS-Lite) process-based forward model oftree growth. We conclude that the removed periodicity does not have a climatic source. Additional evidencefrom direct observation of affected and non-affected trees during defoliation, due to Ormiscodes sp. outbreak in2010, is provided. We also tested the hypothesis of probable masting effects on the growth of N. pumilio at a sitewith a 12-yr record of seed production, but this hypothesis was not confirmed. Taking into account the nonclimaticnature of this signal, we explore the utility of corrected chronologies for reconstruction of climaticparameters in Tierra del Fuego, especially for summer temperature and frost day frequency. This study is the firstsystematic analysis of the pronounced high-frequency cyclicity in N. pumilio tree growth in southernmost SouthAmerica.