Reconstruction of the Standardized Precipitation-Evapotranspiration Index for the Western Region of Durango State, Mexico

In recent decades, droughts associated with climate change have increased in frequency and intensity. Given this trend, the understanding of climate variability over time has raised great interest. The main objective of this study was to reconstruct the standardized precipitation-evapotranspiration index (SPEI) from tree rings of Pinus durangensis Martinez at a representative site in the western region of the Durango State, Mexico. To this end, we used radii of 286 cross-sections, which were processed through conventional dendrochronological techniques. In addition, chronologies of total ring and early and latewood were generated, covering 296 years. In parallel, we analyzed the association between the chronologies obtained and the cumulative SPEI for 3, 6, 9, and 12 months. The earlywood residual chronology (EWres) showed the closest association with the six-month cumulative SPEI for February-May (SPEI6(FM)). Thus, the SPEI6(FM) for the past 296 years was reconstructed through a simple linear regression model. In this reconstruction, 18% of the years were wet, 16% dry, and 66% average. In addition, an increase in the frequency of droughts was observed from 1880 onwards, which might have been related to the rise in temperature due to climate warming. Therefore, the annual rings of P. durangensis are suitable for use as a proxy for the reconstruction of historical climatic events in this region of northern Mexico.