Short term effects of compensatory wood ash fertilization on soil, ground vegetation and tree foliage in scots pine stands

A wood ash experiment was set up in a 38-year-old Scots pine stand (forest type - Pinetum vacciniosum) growing on Arenosol. Raw, dry ash (fly ash, not stabilized) and nitrogen fertilizers were applied in the forest. There were 6 variants of the experiment: 1 - 1.25 t ash ha¨¹; 2 - 2.5 t ash ha¨¹; 3 - 5.0 t ash ha¨¹; 4 - 2.5 t ash ha¨¹ and 180 kg N ha¨¹; 5 - 180 kg N ha¨¹ and 6 - control (without ash and nitrogen). The primary effects (3 months - 2 years after the treatment) of wood ash fertilization on soil, soil solution, soil microflora and biological activity, fine roots and mycorrhiza, ground vegetation diversity, tree foliage chemistry, physiological parameters and litterfall are presented in the paper. The highest wood ash dose (5.0 t ha¨¹) changed the chemistry of forest litter: the increased pH and total concentrations of most of the macronutrients were found after 2 years. In contrast, total N concentrations decreased due to ash application. Wood ash increased the number of ammonifying, denitrifying microorganisms and cellulose - decomposers in the forest litter 3 months after application. Wood ash slightly reduced total length of fine roots and number of root tips 1 year after treatment. The highest degree of fine roots vitality was found in the plots treated with 2.5 - 5.0 t ha¨¹ of wood ash. No changes in ground vegetation diversity were found after the wood ash and N application. No changes of chlorophyll a, b were determined in the current year needles 5 months after application of wood ash. Wood ash decreased the content of the aminoacid proline and it has increased only after N additionLietuvos miškų instituta