Contrasting patterns of local adaptation and climate resilience across forest management regimes in Norway spruce (Picea abies): implications for reforestation practices under climate change

This study investigates the contrasting patterns of genetic diversity and local adaptation between old-growth and recently planted Norway spruce (Picea abies) stands in northern Sweden. We assess neutral genetic variation, adaptive genetic differentiation, and the potential for future adaptation using samples collected from old-growth forests and recently planted stands. Our results reveal no significant differences in overall genetic diversity between natural and planted populations, indicating that current forest management practices have not substantially reduced genetic variation. However, analyses of adaptive variation demonstrate stronger signatures of local adaptation in old-growth populations, with clear correlations between genetic and environmental distances. In contrast, planted stands show weaker adaptive signals and are at greater risk of non-adaptiveness under future climate scenarios. These findings highlight the importance of conserving and promoting adaptive genetic variation within forest management to ensure resilience against ongoing climate change, while also recognising that current practices preserve much of the neutral genetic diversity necessary for long-term forest health.