Climate change is expected to increase the frequency, duration, and severity of droughts across the Mediterranean region, with significant consequences for forest ecosystems. Cork oak (Quercus suber L.) is a species of high ecological, cultural, and economic value in Portugal and has evolved several adaptations to seasonal water scarcity. However, future drought conditions may exceed the limits of these adaptations, increasing the risk of growth decline and mortality. Understanding how climate influences cork oak growth, and resilience is therefore essential for developing effective management and adaptation strategies.

Dendroecology provides a powerful approach for investigating tree responses to environmental change. By analysing annual growth rings, it is possible to reconstruct growth patterns over time and relate them to past climatic conditions. Tree-ring width reflects xylem formation and growth, which is closely linked to water transport, carbon allocation, and overall tree vitality. Favorable conditions generally promote wider rings, whereas drought and other stressors often result in reduced radial growth. In Mediterranean tree species, tree rings can therefore serve as natural archives of climate-growth relationships and help identify early signals of decline, including processes associated with cambial limitations and hydraulic dysfunction.

Remote sensing complements dendroecological approaches by enabling the monitoring of vegetation condition across large spatial and temporal scales. Satellite-derived vegetation indices provide information on canopy greenness and photosynthetic activity and are widely used as indicators of forest health. However, canopy-level spectral responses may not always correspond directly to radial growth or field-based physiological measurements, suggesting potential decoupling between remotely sensed indicators and tree-level processes.

This study examined branch radial growth in cork oak populations distributed across the main range of the species in Portugal. The objectives were to: (1) identify the periods of water availability most strongly associated with radial growth; (2) determine the topographic, soil, and climatic factors that influence growth variability; and (3) investigate the relationship between remotely sensed vegetation indices and radial growth, in order to clarify the links between canopy condition, growth dynamics, and drought resilience.

Preliminary results indicate that radial growth is primarily influenced by cumulative water availability during the two preceding years, suggesting a legacy effect of climatic conditions on woody growth. A decoupling was observed between canopy health and radial growth responses, with radial growth exhibiting greater plasticity in both resistance and resilience to drought.