Pärn, H., Mandre, M. and Tilk, M. 2009. Changes in the Growth of Silver Birch (Betula pendula Roth) and Black Alder (Alnus glutinosa (L.) Gaertn.) Seedlings on Peat Soils Fertilised with Wood and Peat Ashes.   Baltic Forestry, 15 (2): 168-176

The short-term influence of different biofuel ashes on the growth of silver birch (Betula pendula Roth) and black alder (Alnus glutinosa (L.) Gaertn.) seedlings and suitable wood, peat and mixed ash doses for regulating biomass production on peat soil were studied. The experiments were conducted with 1-year-old seedlings planted in vegetation pots. The growth of seedlings for different ash treatments was analysed using the variations in the absolute values of mean annual increments of the height and diameter at the root collar of seedlings, by the final heights and diameters at the end of the experiment, by the increase in height and diameters compared to corresponding initial parameters in the year of the application of ashes and finally the growth of fertilised seedlings was compared with the growth of unfertilised seedlings. In the first growing season the growth of silver birch seedlings of all treatments exceeded that of the control seedlings. In the second growing season the height increments of treatments with higher doses of peat and mixed ash were considerably larger than those for control seedlings. Only the application of the larger doses of peat ash increased significantly the height and radial growth over a 2-year period as a whole compared to the control. Wood ash, particularly the smaller amounts used in experiments, favoured the growth of the black alder seedlings. Along with wood ash peat ash is a promising tool in the afforestation of cut-away peatlands.

Key words: biofuel ashes, cut-away peatlands, fertilisation, silver birch, black alder