Due to complex history of European forests, natural populations may not necessarily represent autochthonous genepools for forest trees. Eastern Prussian forests were famous for using non-local sources for afforestation. We studied efficiency of a set of nuclear microsatellite markers (nSSR) for genetic association and diversity studies of 194 adult trees from 5 populations genotyped at 11 nSSR loci. The Bayesian and UPGMA clustering revealed two genetically distinct groups: (a) the Baltic group, and (b) the Bavarian one and an over 200-years-old sea-side Lithuanian population of Juodkrante from the sea-side Curonian spit of Neringa. We interpret this result as putative introduction of Bavarian Scots pine back in the 18th century, when reforestation efforts were made to sustain moving sands in the dunes of Neringa. The genomic SSRs were more variable than the EST SSRs. However, the association between the variability of the nuclear microsatellite loci and their efficiency in detecting population differentiation was not strong. Keywords: nSSR, Pinus sylvestris (L.), population structure, provenance transfer, FRM transfer, molecular markers