Variation in growth of Norway spruce in the IUFRO 1972 provenance experimental series

Provenance experiments traditionally provide information on genetic variation within tree species in adaptation ability and other traits important for commercial forestry. In this study we investigated variation in growth among 20 populations of Nor­way spruce (Picea abies (L.) H. Karst) at four common-garden sites of the IUFRO 1972 provenance experimental series at the age close to half of rotation. Because stand density varied among sites, we analyzed stand density-adjusted basal area (BA) and quadratic mean diameter (Dq). The examined prove­nances varied significantly in both analyzed traits. We identi­fied provenances that performed consistently better or worse than average across all four sites. Among the well-growing and possibly adaptive seed sources were those from the uplands of the eastern and central Poland, Sudety Mts, and from the regi­on of Istebna in Beskid Mts. Performance of the other populati­ons from Beskid Mountains was average to poor, and all high-altitude populations were poor-growing. The results of this study help to verify the knowledge of genetic variation pattern among Norway spruce populations in Poland, and to guide management decisions regarding spruce planting material.