In the present study, the effect of the seed weight of chestnut-leaved oak on the growth, survival and seed quality index of the produced seedlings was investigated. 800 oak seeds were collected from the branches facing the light in the middle part of the crown of a mature tree in Tamishan Noor region. The collected seeds were classified into four classes including the weight of each seed less than 4 g, 4 to 6 g, 6 to 8 g and more than 8 g. 400 seeds from the above collection were placed in the germinator after dividing into four seed-weight-classes in the laboratory in order to compare the germination percentage. The remaining 400 seeds were planted as four weight classes, including 100 seeds in each class, in nursery of Koloudeh Amol. The results showed that the percentage of seed germination did not have a significant difference among the treatments. However, the seedlings produced from larger seeds reached a higher seedling height at even 3 months and 8 months, and had a larger collar diameter than that, being statistically different. The percentage of survival was also higher in the seedlings obtained from larger oak seeds. Meanwhile, the SQ seedling quality index did not show a statistically significant difference among various seed weight treatments. Since the planting of taller and thicker seedlings has more successful results in terms of competition with invasive plants in the gaps and considering their higher survival percentage, it can be recommended using larger seeds of chestnut-leaved oak in seeding, seedling production in nurseries and planting in forest fields to produce tall oak seedlings.
