Basic physical properties of Norway spruce (Picea abies (L.) Karst.) seeds

The range of variations in a given separation parameter and its relationships with other attributes have to be determined for designing seed cleaning and sorting processes. In this study, those relationships were determined for five batches of Norway spruce seeds supplied by a seed extraction plant in Jedwabno. The seeds were harvested from seed stands in northern Poland. The terminal velocity, length, width, thickness and mass of every seed were determined. The results were used to calculate the geometric mean diameter, aspect ratio, sphericity index and density of the evaluated seeds. Those parameters were compared by analysis of variance and linear correlation analysis. Similarities in the average values of all physical properties were noted only between seeds harvested in the same seed zone, from tree stands occupying the same habitat type. The analyzed seeds can be effectively separated into mass fractions with the use of traditional sorting devices such as pneumatic separators, mesh sieves with longitudinal or round openings, cylindrical graders, winnowing machines and pneumatic sieves, in order to achieve more uniform seedling emergence when each seed fraction is sown separately.