AbstractAfter drought events, tree recovery depends on sufficient carbon (C) allocation to the sink organs. The present study aimed to elucidate dynamics of tree‐level C sink activity and allocation of recent photoassimilates (C_new) and stored C in c. 70‐year‐old Norway spruce (Picea abies) trees during a 4‐week period after drought release. We conducted a continuous, whole‐tree ¹³C labeling in parallel with controlled watering after 5 years of experimental summer drought. The fate of C_new to growth and CO₂ efflux was tracked along branches, stems, coarse‐ and fine roots, ectomycorrhizae and root exudates to soil CO₂ efflux after drought release. Compared with control trees, drought recovering trees showed an overall 6% lower C sink activity and 19% less allocation of C_new to aboveground sinks, indicating a low priority for aboveground sinks during recovery. In contrast, fine‐root growth in recovering trees was seven times greater than that of controls. However, only half of the C used for new fine‐root growth was comprised of C_new while the other half was supplied by stored C. For drought recovery of mature spruce trees, in addition to C_new, stored C appears to be critical for the regeneration of the fine‐root system and the associated water uptake capacity.