Declining pine growth in Central Spain coincides with increasing diurnal temperature range since the 1970s

• 871 Scots pine ring width samples were collected at 18 plot sites in Central Spain.
• Individual tree ages of 6–175 years are comprised in a dendrochronological network.
• Central Spanish pine growth correlates at − 0.84 with the May–July DTR back to 1956.
• Positive pressure anomalies of the NAO trigger negative Scots pine growth extremes.
• Long-term declining forest growth coincides with Iberian drying since the 1970s.

Growing evidence suggests environmental change to be most severe across the semi-arid subtropics, with past, present and projected drying of the Mediterranean Basin posing a key multidisciplinary challenge. Consideration of a single climatic factor, however, often fails to explain spatiotemporal growth dynamics of drought-prone ecosystems. Here, we present annually resolved and absolutely dated ring width measurements of 871 Scots pines (Pinus sylvestris) from 18 individual plot sites in the Central Spanish Pinar Grande forest reserve. Although comprising tree ages from 6 to 175 years, this network correlates surprisingly well with the inverse May–July diurnal temperature range (r = 0.84; p < 0.00011956–2011). Ring width extremes were triggered by pressure anomalies of the North Atlantic Oscillation, and the long-term growth decline coincided with Iberian-wide drying since the mid-1970s. Climate model simulations not only confirm this negative trend over the last decades but also project drought to continuously increase over the 21st century. Associated ecological effects and socio-economic consequences should be considered to improve adaptation strategies of agricultural and forest management, as well as biodiversity conservation and ecosystem service.