Varying selection differential throughout the climatic range of Norway spruce in Central Europe

Predicting species distribution changes in global warming requires an understanding of how climatic constraints shape the genetic variation of adaptive traits and force local adaptations. To understand the genetic capacity of Norway spruce populations in Central Europe, we analyzed variation of tree heights at the juvenile stage in common-garden experiments established from the species’ warm-dry to cold-moist distribution limits. We report the following findings: first, 47 % of the total tree-height variation at trial sites is attributable to the tree populations irrespective of site climate. Second, tree height variation within populations is higher at cold-moist trial sites than at warm-dry sites and higher within populations originating from cold-moist habitats than from warm-dry habitats. Third, for tree ages of 7 to 15 years, the variation within populations increases at cold-moist trial sites, whereas it remains constant at warm-dry sites. Fourth, tree-height distributions are rig...