The presented study identifies the existing dependencies between the time course of phenological phenomena in the oak stands, from three sample surfaces, and the factors with a major impact on their evolution. The usefulness of the oak tree research is necessary both for scientific and practical reasons, knowing that the issue of ensuring the production of high quality forest seeds and the necessary quantity is an actual one. The researches show that the formation and development of the oak inflorescences, the amount of acorns reached maturity and the degree of its viability (in the region under study) were in direct correlation with the climatic parameters, during the vegetation period, the presence of defoliating and seminophage species , factors that can induce tree metabolic imbalances, low fructification, and premature fall of fruit. The most intense fructification was certified for the Ivancea research area, followed by the Codrii and Mereşeni areas.