The aim of the study was to investigate the effect of fertilization on the growth of Silver birch Betula pendula Roth and Scots pine Pinus sylvestris L. seedlings on a cutaway peatland (Ulila, 58°22'N, 26°26'E). Five treatments were established: wood ash (10 000 and 5000 kg/ha), peat and wood ash mixture (10 000 and 5000 kg/ha) and control (unfertilized field). Results of analysis showed that the pH of peat in the cutaway peatland was before treatment 3.5 and it rose after fertilization by up to 0.7 units by the end of the first growing season. The treatment with 10 000 kg/ha of wood ash gave the best results: the annual height increment of Silver birches during the first growing season after fertilization was 4.5 times higher and that of Scots pines 1.1 times higher than control. In the second growing season after fertilization the increment was respectively 16.3 and 3.3 times higher than control. The root collar diameters of Silver birches were 4.4 time larger these of Scots pines 2.1 times larger than control. Scots pine needles were 2.2 times longer than control and the leaf area of the Silver birches was 6 times larger than control, which also shows a positive effect of fertilization. Peat ash treatment was also favourable, although its effect was much smaller than the effect of wood ash.
