Tlıis article deseribes the quantity and quality of seed yields, their annual variations, and periodic dispersal within the year for populations of different site classes, age categories, and elevations together with the effects of silvicultural treatm ents in Pinııs sylvestris, Pinııs nigra subsp. pallasiana, and Pinııs brııtia in Turkey. Seed crop per urıit area (square m eter) was m easured at sample plots vvlıich were chosen from even-aged, pure pine stands \vith a norm al, even-aged structure by using pyram id-slıaped metal seed traps m ounted on a woodeıı or metal fram e. The results revealed that seed yield was higher in good site classes. In general, annual fluctations of seed crops \vere in the same direction during each year in ali sample plots for a given species. Populations of middle age of each tree species generally produce m ore seeds for the same site classes and elevation zones. The pine species witlı lighter seed >veights produced greater seed yields (num bers). Seed crops at the middle elevation zone w ere more abundant than Iower and/or upper elevation zones. R hythm s of seed dispersal generally occured during the same periods within each year for each tree species. Tlıese rhythm s are vvell correlated with climatic conditions and the geograplıic distribution of the species to enable it to secure future generations. In general, empty seed percentages \vere positively correlated w ith poor site classes, poor seed years, very old stands, and higher elevations.