Tree Rings Elucidate Differential Drought Responses in Stands of Three Mexican Pines

Abstract

Knowledge regarding the growth of trees is essential to understanding their response to predicted warmer and drier climate scenarios. We used the annual rings of three Mexican pines (Pinus montezumae Lamb., Pinus oocarpa Schiede ex Schltdl., and Pinus monophylla Torr. & Frém) to explore their drought responses. Correlation analyses showed that hydroclimatic factors differentially impact tree species in terms of the intensity and temporality. The negative influence of the maximum temperature and positive effect of the precipitation on the growth indices were notable, with P. montezumae being the most responsive species, followed by P. oocarpa and P. monophylla. The climate–growth relationships were specific and driven by the differential hydrothermal conditions across the study areas. SPEI analyses indicated that P. monophylla is better able to tolerate drought than P. montezumae or P. oocarpa, especially in recent years. The lower resilience of P. montezumae and P. oocarpa could predispose them to a higher mortality risk if warming and drying rates increase. Our findings strengthen the understanding of the responses of tree growth to seasonal drought, which is critical considering the biogeographic shifts that will potentially be experienced by these forests in the future. This knowledge improves the understanding of young Mexican stands and could contribute to the design of management strategies in the face of predicted climatic variations.

Keywords

• conifers
• dendroecology
• drought
• radial growth
• tree mortality