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Naturally regenerated seedlings or saplings in post-harvest forest stands are expected to contribute to population regeneration and the restoration and maintenance of genetic diversity in forest trees. In this study, we used intact old-growth stands of dragon spruce (Picea asperata Mast.) as a benchmark to compare genetic diversity between mature and progeny cohorts sampled from post-harvest planted and post-harvest naturally regenerated stands in western Sichuan, China. Mature cohorts in the intact stands exhibited the highest levels of genetic diversity among the three types of stands. Genetic diversity within the progeny cohorts in the intact stands was significantly lower than their parent cohorts for all five measures of diversity. The progeny cohorts of the intact stands had lower genetic diversity than progeny cohorts from two types of post-harvest stands, but only for two measures of diversity. There were no significant differences in diversity between the mature or progeny cohorts of the planted and naturally regenerated stands. When mature and progeny cohorts were pooled, genetic variation within the united sample was enriched and close to that of the mature cohort in the intact stands. High genetic similarity and low genetic differentiation between progeny cohorts in the post-harvest stands and mature cohorts in the intact stands indicated a sufficient seed or pollen migration from the surrounding intact stands into the regenerated area. These findings illustrate the important role of the mature cohorts in the intact stands as reservoirs of genetic diversity. [ABSTRACT FROM PUBLISHER]