Disrupting tree continuity through clearcut forestry can alter the climate sensitivity of future tree growth in northern Sweden

Disrupting tree continuity through clearcut forestry is a widespread management practice across the boreal biome. However, concerns remain that forests regenerated after clearcutting may be more sensitive to climatic fluctuations. We examined how clearcutting affects tree growth responses to weather variability, focusing particularly on the extreme 2018 drought. We collected tree-ring width data from forests in northern Sweden that either were clearcut ∼60 years prior to the study or never had been clearcut but exposed to past selective logging. We tested whether growth responses to interannual weather variations variables differed between these forest types and assessed how the differences were mediated by soil organic matter, soil temperature stability, and variations in tree age, size, and early growth rates. Forests regenerated after clearcutting showed greater responsive to interannual variation in weather, being more negatively affected by increasing temperature but more positively affected by precipitation. During the 2018 drought, clearcut forests exhibited a mean growth reduction of 19 %, compared to 11 % in non-clearcut forests. The higher drought resistance in non-clearcut forests was primarily associated with greater mean tree age and slower early growth rate. However, as these variables are strongly correlated with clearcutting history, their independent mediation effects are difficult to interpret. Our results suggest that clearcut forestry may increase the sensitivity of regenerating forests to climatic variability. Further research is needed to disentangle the underlying mechanisms and to determine how forest management practices can promote greater climatic resilience in boreal ecosystems. • Tree growth was compared between clearcut (60 years ago) and non-clearcut forests. • Growth was more negatively affected by increasing temperature in clearcut forests. • Drought resistance was associated with high age and slow growth rates of trees.