Moderate effects of species mixing on the growth and drought response of Austrocedrus chilensis in northern Patagonia

FACCIANO, LORETA; SASAL, YAMILA; SUAREZ, MARÍA LAURA

Dendrochronologia

ELSEVIER GMBH, URBAN & FISCHER VERLAG

Año: 2025 vol. 90 p. 1 - 13

1125-7865

Acceleratedclimate warming, marked by rising temperatures and reduced precipitation,intensifies droughts, causing severe impacts on forest ecosystems. Themechanisms underlying the loss of tree vigor due to climate warming, are notfully understood. Overall, it appears that vigor loss is moderately controlledby regional climatic patterns and species admixture, as intra- andinter-specific interactions within a stand influence tree growth and droughtperformance. However, the role of the species mixing under climatic stressremains inconclusive. Here, we applied a dendroecological approach to assessgrowth trends, climatic responses, and drought performance in Austrocedruschilensis trees growing under three species stand mixtures (pure, mixed, and diverse)in Patagonia, Argentina. Along the precipitation gradient, the generalrelationship between A. chilensis growth and moisture availability is driven byregional climatic conditions, while the response to individual extreme eventsis modulated by species mixing. We found that trees in mixed and diverse standsexhibited a positive growth trend in the recent decades, suggesting abeneficial effect of species combination; though the evidence remains limitedon whether this complementarity lessens growth response during droughts. The droughtresponse of A. chilensis was mainly shaped by the precipitation gradient ratherthan by stand admixture effects. However, species mixing may buffer regionalclimate impacts, slightly enhancing drought resilience. Comparing nearby standswith different compositions (pure vs. mixed) revealed varying climate-growthrelationships, suggesting a coherent species-mixing effect on species growth.In conclusion, this relationship between stand diversity and functioningappears to be influenced by site-specific factors and species identity.