Neighborhood context mediates drought susceptibility at the individual tree level in Patagonian forests

Abstract

Extreme droughts are becoming more frequent and intense, with growing impacts on terrestrial ecosystems. In forested regions, climate-driven disturbances are altering ecological dynamics, particularly affecting tree growth. Responses to these stressors vary widely among species, sites, and even individual trees, reflecting the influence of multiple interacting factors. In northern Patagonia, several native tree species have shown growth declines, with severity depending on species identity and local conditions. Among these factors, interactions with neighboring trees—through competition or facilitation—can modulate individual responses to climatic stress. This study examines how Austrocedrus chilensis, a widespread conifer of temperate forests, responds to climatic anomalies across different forest compositions. We applied a dendroecological approach to assess 30 years of radial growth (1990–2020) in dominant individuals located in monospecific, mixed, and diverse forest stands along a regional precipitation gradient. We incorporated information on neighboring species identity and competition indices to explore how the biotic context shapes individual responses. Our results show that neighborhood composition and microsite conditions significantly influence growth patterns. In particular, trees growing with heterospecific neighbors exhibited higher resistance and recovery following drought events compared to those in conspecific neighborhoods. Additionally, both drought and wet extreme events left distinct imprints on growth trajectories. These findings underscore the importance of local biotic interactions and site conditions in modulating tree resilience under climate variability. Incorporating these factors into forest management and climate adaptation strategies will be key to promoting the persistence of A. chilensis and the ecosystems it inhabits.