Abstract

VEGA, Leticia; MARCOTTI, Eugenia  and  AMOROSO, Mariano M. Variation in the growth patterns prior to death of individuals of Austrocedrus chilensis along a pluviometric gradient in the North of Andean Patagonia. Ecol. austral [online]. 2019, vol.29, n.2, pp.208-222. ISSN 1667-782X.

The Andean-Patagonian forests are home to one of the endemic conifers of South America: Austrocedrus chilensis (D. Don) Pic. Ser. Et Bizzarri (Cupressaceae). The occurrence of episodic mortality events along the gradient of distribution of this species makes necessary studies to shed light on allow advance on the responses of trees to these tree behaviors in these events. The objective of this research is to study of the growth patterns prior to the death of individuals of Austrocedrus chilensis in a W-E precipitation gradient. Specifically, the area includes the northern distribution of the species in northern Patagonia, Argentina. Nine sampling sites were selected along a west-east transect in the vicinity of Traful Lake, Neuquén province, which captures a precipitation gradient of 1800 to 600 mm/year. Patterns and growth rates were analyzed in the 5, 10 and 15 years prior to death along the gradient. The results obtained allowed to establish that according to the variability of the growth patterns ordered in two analyzed forests were ordered in two large groups: mixed-compact and compact-ecotonal. In turn, these differences were related to particular conditions of the chronologies (e.g., the ring width index) and biophysics (e.g., slope, exposure, latitude and longitude) of the study sites. The rates of growth prior to death allowed to determine that in all the study sites, individuals presented a decrease in radial growth prior to this event; in turn, for the same time windows, dead individuals grew less than living individuals. It is necessary to deepen the studies to know the mechanisms by which these growth patterns are ordered prior to death along the Andean-Patagonian gradient.

Keywords : Mortality; Precipitation gradient.

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