Earlywood and Latewood Widths of Picea chihuahuana Show Contrasting Sensitivity to Seasonal Climate

The existence of endangered tree species in Mexico necessitates an understanding of their vulnerability to the predicted climate changes (warming and drying trends). In this study, the sensitivity to climate of earlywood (<i>EW</i>) and latewood (<i>LW</i>) widths of the threatened <i>Picea</i> <i>chihuahuana</i> was determined. The response of <i>EW</i> and <i>LW</i> to climate variables (maximum temperature, minimum temperature, precipitation, evaporation, and a drought index) was analyzed by means of correlation analysis using dendrochronology over the period of 1950–2015. <i>EW</i> and <i>LW</i> production were enhanced by cool and wet conditions during winter prior to the start of growing season. During the growing season, <i>EW</i> and <i>LW</i> production increased in response to cool spring and summer conditions, respectively; temperatures and year-round evaporation, excluding summer and the previous drought in the period prior to the growing season. <i>EW</i> was sensitive to seasonal drought, which is a concern considering the predicted aridification trends for the study area. These results provide further knowledge on the dendroecological potential of <i>Picea chihuahuana</i>.

Funding was provided by CONACYT (Consejo Nacional de Ciencia y Tecnología) through the CB-2013/222522 project. Many thanks to the community-based site known as “Ejido el Brillante”, and we also thank the forester responsible for the area (Javier Bretado) for supporting the data gathering. We thank the Dirección General de Vida Silvestre, SEMARNAT (Secretaría de Medio Ambiente y Recursos Naturales), Mexico, for providing technical facilities. Gabriel Sagüesa contributed with sample processing. The authors are grateful to the editors and anonymous reviewers for their useful comments and suggestions.

We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).