High-Resolution Temperature Variability Reconstructed from Black Pine Tree Ring Densities in Southern Spain

• Main Authors: Jan Esper, Claudia Hartl, Ernesto Tejedor, Martin de Luis, Björn Günther, Ulf Büntgen
• Format: Article
• Language: English
• Published: MDPI AG 2020-07-01
• Series: Atmosphere
• Subjects: maximum latewood density; climate reconstruction; dendrochronology; forest ecosystems; climate change; Pinus nigra
• Online Access: https://www.mdpi.com/2073-4433/11/7/748

The presence of an ancient, high-elevation pine forest in the Natural Park of Sierras de Cazorla in southern Spain, including some trees reaching >700 years, stimulated efforts to develop high-resolution temperature reconstructions in an otherwise drought-dominated region. Here, we present a reconstruction of spring and fall temperature variability derived from black pine tree ring maximum densities reaching back to 1350 Coefficient of Efficiency (CE). The reconstruction is accompanied by large uncertainties resulting from low interseries correlations among the single trees and a limited number of reliable instrumental stations in the study region. The reconstructed temperature history reveals warm conditions during the early 16th and 19th centuries that were of similar magnitude to the warm temperatures recorded since the late 20th century. A sharp transition from cold conditions in the late 18th century (t₁₇₈₁_–₁₈₁₀ = −1.15 °C ± 0.64 °C) to warm conditions in the early 19th century (t₁₈₁₈_–₁₈₄₇ = −0.06 °C ± 0.49 °C) is centered around the 1815 Tambora eruption (t₁₈₁₆ = −2.1 °C ± 0.55 °C). The new reconstruction from southern Spain correlates significantly with high-resolution temperature histories from the Pyrenees located ~600 km north of the Cazorla Natural Park, an association that is temporally stable over the past 650 years (r₁₃₅₀_–₂₀₀₅ > 0.3, p < 0.0001) and particularly strong in the high-frequency domain (r_HF > 0.4). Yet, only a few of the reconstructed cold extremes (1453, 1601, 1816) coincide with large volcanic eruptions, suggesting that the severe cooling events in southern Spain are controlled by internal dynamics rather than external (volcanic) forcing.