Mating systems have long been recognized as key factors determining genetic structure within and between pop- ulations. Outcrossing promotes genetic diversity and gene flow between populations, while inbreeding, on the other hand, decreases recombination rates, facilitating fixation of co-adapted genes. In small populations, selfing moderates pollen limitation because of low mate availability, but at the cost of increased inbreeding depression. These conflicts are of more than theoretical interest; they are critical for the man- agement of endangered species. In order to help designing conservation strategies for the management of the gene pool of fragmented populations of Pinus cembra, a protected spe- cies in Poland, we have characterized pollen flow and mating structure using nuclear microsatellite markers. We demon- strated that P. cembra in the studied stands of the Tatra Mts. is characterized by an average outcrossing rate (t )o f 0.72. Unlike with the existing approaches, using the newly devel- oped Bayesian method, we found that population size and seasonal variation had confounding effects on outcrossing rates. In concordance with predictions, large populations showed significantly higher outcrossing rates (t=0.89) than smaller ones (t=0.51). Temporal variation revealed in the outcrossing rate might be linked with masting behavior of the species. On the other hand, we showed that outcrossing rates were not associated with a trunk diameter of a mother tree. Our study also demonstrated that biparental inbreeding is a significant component of mating system. However, we further show that pollen dispersal follows a fat-tailed distribu- tion (with the average dispersal distance of 1,267 m) so that at least some long-distance pollen dispersal must be occurring. Overall, we conclude that the high inbreeding (both selfing and mating between relatives) found in P. cembra buffers for