This article describes the quantity and quality of seed yields, their annual variations for populations of different site classes, age catagories and effects of silvicultural treatments in Pinus sylvestris in Eskişehir-Çatacık forest region. The study covers a period of 6 years between the years 1974 and 1979. In one of the previous research which covered three years (1971-1973) at the same sample plots has been concluded and published (Boydak, 1975; Boydak, 1977). So together with this research 9 years (1971-979) of the seeding characteristics of Pinus sylvestris was obtained. The study area was located on the northern slopes of the Sundiken Mountains. Fiveteen sample plots were chosen in pure and even-aged scots pine stands with normal constitution to determine seed crop in Çatacık region. Every sample plot had an area of 0.25 hectar (50x50 m). 20 seed traps each with a surface area of 1/10 square meter were systematically placed in the sample plots of middle aged and older selected stands, while 30 traps were placed in each young populations. The results indicated that, in general, seed yiled was higher in good site classes, and middle ages populations in scots pine. Silvicultural treatments (thinings) slightly increased the seed crop in Pinus sylvestris. Seed productivity of 15 populations showed the same paterns from year to year. Good seed years have repeated 2-3 years intervals. Moreover good seed years together with medium seed years have occured either consecutive years or every two years. In general, empty seed percentages were positively correlated with poor site classes and old stands. The results of the investigation revealed that seed stands should be chosen over 40-45 years of age in the natural scots pine stands with superior quality in Çatacık region. When necessary seed collection could also be made from old stands such as 180-200 years of age.