Intensity of seeding and quality of Scots pine (Pinus sylvestris L.) seeds on permanent observation plots subjected to forest monitoring between 1996 and 2003
Forest monitoring programme in Poland was introduced in 1984. In 1996, forest monitoring embraced assessment of seed production and quality of Scots pine (Pinus sylvestris L.). Every year, seed samples with the mass of ca 1 kg are being collected from hundred second-level Permanent Observation Plots located in various regions of Poland. The assessment of seeds aims at determining differences in seed output from cones and quality of Scots pine among natural-forest regions, as well as their variability over time. Investigated were the following indicators: mass of one cone, output of seeds from cones, number of full seeds, mass of 1000 seeds, germinative energy and germinating capacity, difference in germinating capacity between aged and non-aged seeds, length and width of embryo and length and width of endosperm. Eight-year observations on intensity of seeding and seed quality of pines point out to confirmed statistical differences in seed output quality of seeds among both study years and natural-forest regions. Distinct regularity was found according to which the variability in seeding output of pine across Poland is greater than the variability in quantitative traits (except for the resistance to aging test). The lowest seed output and the smallest seed mass, as well as the smallest size of embryos was found in the Mazury-Podlasie Region II. Forest monitoring results can be used in full as soon as reference levels (long-term means) are defined for pine seed output and quality indicators in different regions (natural-forest regions) of the country.
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