Annual radial growth and climatic response of Quercus crassifolia bonpl. in northwestern Durango, Mexico

Abstract

The oak species Q. crassifolia produces reliable annual rings with better climatic sensitivity than many conifer species commonly used for hydroclimatic reconstructions in Mexico. Most dendrochronological research in Mexico has been done with conifers, but broadleaf species have been underutilized. Mexican oaks are found among those species receiving limited attention for dendrochronological purposes, despite Mexico being a primary center of oak diversity with over 160 species. The objectives of this study were: (1) date the annual radial increments of oaks (Quercus crassifolia Bonpl.), and (2) analyze the dendrochronological potential and climatic response of the species to reconstruct historical climatic variability and the influence of ocean–atmospheric modes. The study was located at the Barajas site, municipality of Tepehuanes, Durango, Mexico. Wood samples consisted of 60 cross sections, 30 of them obtained at the base of the stem, and 30 more ca. 20–30 cm above the first cross section, which were analyzed by dendrochronological techniques. A tree-ring width chronology 177 years long (1840–2016) was developed indicating suitable values of series intercorrelation (0.52), mean sensitivity (0.26), signal-to-noise ratio (8.98), first-order autocorrelation (0.21), rbar (0.28), and expressed population signal (0.86) for the period 1890–2016. Dendrochronological parameters were similar or superior to those obtained from conifer species in the region. The chronology shows the strongest relationship with October–May precipitation, explaining ca. 60% of its variability (1951–1984, r = 0.78, p < 0.01), but a negative response to the average seasonal October–May temperature (1902–2016, r = -0.50, p < 0.01). The annual growth rings of Q. crassifolia showed a negative association (1890–1977, r = – 0.67, p < 0.01) with the El Nino-Southern Oscillation (reconstructed Southern Oscillation Index), and positive with the Pacific Decadal Oscillation Index (1948–2015, r = 0.39, p < 0.01, the reconstructed Palmer Drought Severity Index (1890–2012, r = 0.73, p < 0.01), and the seasonal winter–spring Standard Precipitation Index (1890–2016, r = 0.76, p < 0.01).