The study material consisted of 13 rather old Norway spruce (Picea abies (L.) H. Karst.) and 17 Scots pine (Pinus sylvestris L.) stands located in different parts of Finland. In each stand the seed crops, radial growth and amount of latewood were measured during a period of about ten years. Seed production reduces the radial growth of spruce and pine in the year of seed maturing. In Southern and Central Finland also the proportion of latewood is reduced. Seed production accounts for about 14% of the variation in radial growth of a spruce stand growing in Lapland, and 27% in other parts of Finland. In pine stands the seed crop explains 19% of the variation in radial growth in Lapland, and only 7% in the rest of Finland. In spruce stands an average seed crop reduces radial growth by 14% in Lapland and 5% in the rest of the country. An abundant seed production causes a reduction of about 20%. In southern parts of Finland, the proportion of latewood is reduced by 5% in an average seed year and by 24% in a good seed year. In pine stands an average seed crop decreases the width of annual ring by 5%, and a good seed crop by 15%. Outside Lapland, also the proportion of latewood is reduced: in an average seed year by 5%, and in a good seed year by 16%. The reduction in volume growth of spruce stands due to an average seed crop was estimated to be about 10% in Lapland, and 6% in other parts of Finland. A prolific seed production causes a reduction of 20%. In old pine stands the reduction is 5% in an average seed year, and 15% in a good seed year.
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Initial fertilisation, when the fertilizer is supplied during the plantation, is applied to improve the competitive ability of the seedlings and hence to increase their growth and productivity; however, fertilization could also alter wood properties and timber quality. In this study, the dimensions and tree-ring parameters – width, proportion of latewood, maximum and mean density, mean earlywood and latewood density – of initially fertilized (by 14, 6 and 11 g of N, P and K per seedling, respectively) Norway spruce (Picea abies Karst.) growing in an experimental plantation in Kalsnava, Latvia (temperate climate region) were assessed. The fertilization significantly increased the dimensions of trees in long-term (ca. 17% increase of stemwood volume). The analysis of tree-ring width suggested that the duration of the effect was ca. 15 years. The maximum and latewood density were higher for the fertilized trees only in a few years. The mean and earlywood density of tree-rings were mainly similar for both treatments. Altogether, considering the one-time application of a limited amount of fertilizer, such treatment had notable and lasting effect on Norway spruce.