Tree-rings and climate relationships for Douglas-fir chronologies from the Sierra Madre Occidental, Mexico:: A 1681-2001 rain reconstruction

Five Pseudotsuga menziesii chronologies from the Sierra Madre Occidental were used for comparative climate-growth association purposes. Two new site chronologies were constructed for the first time; dated total tree-ring raw data of three additional site chronologies, previously documented, were used to compute comparable chronologies. Correlation analysis among the five chronologies reveals significant statistical association between most of them (r = 0.33-0.72; p < 0001). All chronologies were used individually to examine climate-growth associations considering both, local and regional climate data obtained from four meteorological stations in the region. Total regional precipitation correlated extremely well with standardized growth indices (up to r = 0.84; p < 0.0001); maximum temperature had an inverse association with growth, correlating lowly but significantly (up to r = -0.62;p < 0.0001), while minimum and mean temperatures did not correlate at all. The Las Bayas, a new chronology, was the highest correlated with regional November-May and November-August total precipitation (r = 0.80; p < 0.0001 and r = 0.84; p < 0.0001, respectively). Using Las Bayas chronology total November-May regional precipitation was reconstructed from 1681 to 2001 and used to identify the main dry and wet periods during the last three centuries. Most of the drought and wet episodes identified were consistent with those reported earlier for northern Mexico; an important exception was the 1950s interval that has been recognized widely as one of the most severe droughts in this region, and that based on reconstruction presented in this study was identified as a rather wet episode. The presence of wintertime El Nino events and chronologies were statistically related indicating that wet and cold winters in the Sierra Madre mountain range enhance diameter growth of fir trees. Further studies are recommended to update and extend the present chronologies as well as the exploration of new sites and species to extend the network of climate sensitive chronologies in this region. (c) 2005 Elsevier B.V. All rights reserved.