The relicts of stone pine forests on marly or even gypsiferous slopes with high pH values induced the hypothesis of a possible genetic adaptation to this site types, marginal for a species normally growing on siliceous sandy plains. Actually, the forest reproductive materials from selected seed stands on those slopes are used preferably for forestations on analogous sites. In 1998, a multi-site comparative test was established with plant lots obtained from seven selected seed stands and two non-selected seed sources. At least up to the age of eight years, the saplings did not show any significant differentiation among basic materials in outplanting success, survival, vegetative phase change, height or diameter growth, whereas a common, strong phenotypic plasticity among test sites was observed. Hence there seems to be no reason for managing separately seed lots and plants of the same provenance and certify category (e.g. selected reproductive material) instead of mixing them.