8. Intensity of seeding and quality of Scots pine seeds on the second-level POPs

Plate 12. Current year cones of Scots pine (Pinus sylvestris L.) - photo by Jerzy Wawrzoniak

The research results for seeding and quality of Scots pine seeds are used both in the biological monitoring and current economic activity of the State Forests. Preliminary information about the production and viability of seeds of Scots pine from different regions of Poland sent to the Regional Directories of the State Forests in December can make the decision about seeds collection and extraction easier.

In 2002, likewise in the last seven-year observation period, the variability coefficients of indicators of seeding were significantly higher than the variability coefficients of the quality characteristics (Tab. 9) and exceeded the level of 20%. The variability coefficient of the mean cone mass was similar to the value of the long-term mean. The variability coefficients of the number of full seeds per cone and the weighed output from cones were distinctly higher than the mean over the last seven years. The values of the variability coefficient of the mass of 1000 seeds (13%) and length and width of endosperm (6% and 6%, respectively) were the same as the long-term means. The seeds were characterised by a significantly lower variability of germination capacity. The value of the variability coefficient of the quality characteristics showing the highest variability i.e. the resistance of seeds to the accelerated aging test was two times higher than the long-term mean and approached to 285%.

In 2002, the country mean weighed output of seeds from cones slightly exceeded the long-term mean, as well as the output (1.50%) considered average in forest management [8]. This resulted exclusively from the higher average number of viable (full) seeds per cone (by 2 seeds). The mean mass of 1000 seed approximated the long-term mean, and the mean mass of one cone was even slightly greater than the last seven-year mean. In spite of satisfactory mean values of seeding indicators, significant differences were found between the natural-forest regions of the country. The indicators of seeding for 6 compared regions were higher than the long-term means with the exception to the Carpathian natural-forest region. The values for these indicators in this region decreased by 1 and were lower than in the Mazury-Podlasie natural-forest region where conditions of high seeding based on the long-term observations were the least favourable. ANOVA and Tukey's test confirmed significance of differences in the numbers of viable seeds per cone between the Carpathian and Wielkopolska-Pomorze, Mazowsze-Podlasie and Silesian natural-forest regions, and expressed as the weighed output of seeds - also the Małopolska natural-forest region.

In 2002, the pine seeds from most natural-forest regions were shapely. The mean mass of 1000 seeds approximated to 6.5 g, i.e. the value of the last seven-year mean and it greatly exceeded 6.1 g, i.e. the mass considered average in forest management [8]. Likewise, the dimensions of an embryo approximated to the long-term means, and the dimensions of an endosperm were even greater. However, seeds collected in the Carpathian natural-forest region significantly differed from the mean: The values of the mean masses and dimensions of embryo were definitely lower than the long-term means for the country and the region. The mean length and width of embryo approximated to the lower limit for seeds of I quality class [21]. ANOVA and Tuckey's test confirmed that the width of embryos in seeds collected in the Silesian natural-forest region was significantly greater than seeds collected in the Carpathian natural-forest region (Ryc. 15), and the mean width of endosperm was significantly smaller than in the Baltic natural-forest region. Other differences were not proved significant. The declining mass of the 1000 seeds and the dimensions of endosperm in seeds collected in the Carpathian natural-forest region was, to a great extent, influenced by the lowered values of these indicators for seeds collected in the monitoring plots in the Beskid Niski: Rymanów and Dukla Forest Districts.

Similar differences were found in the viability of seeds. In 6 natural-forest regions, the mean germination capacity and germinative energy, as well as the resistance of seeds to the accelerated aging test were generally higher than the last seven-year means (Tab. 9). The values of these indicators in the Carpathian natural-forest region were found markedly lower than the long-term means and the means in all other natural-forest regions. ANOVA and Tuckey's test proved significant differences in germination capacity of seeds between the Carpathian natural-forest region and the Wielkopolska Pomorze, Mazowsze-Podlasie, Silesian and Małopolska natural-forest regions. A decrease in viability of seed from the Carpathian natural-forest region was mainly due to the decreased (by one class) germinating capacity and germinative energy, as well as the resistance of seeds from the Rymanów Forest District to the accelerated aging test (decreased germinating capacity by 34%). Differences in germinating capacity between aged and non-aged seeds were found significant (15-18%) for seeds collected on 3 monitoring plots from different regions of the country (Gryfino, Bogdaniec and Nowogród Forest Districts). However, the lower values of these indicators did not entail the lowering of the mean characteristics for the natural-forest regions in which the plots are located.