The objective of this study was to evaluate natural forest regeneration in cutovers on drained fens (eutrophic and mesotrophic low moor peat soils) depending on intensity of drainage characterised by depth of the ground water table, coverage of ground by vegetation and soil chemical properties (soil acidity and saturation with bases). The data were collected in 172 sample plots established in transects located perpendicular to drainage ditches at different distance to it. The assessments were carried out in 2003-2007 in the Panevėžys and Biržai state forest enterprises.

It was found that downy birch (Betula pubescens) seedlings dominated in cutovers on eutrophic and mesotrophic fens. The density of seedlings was greatest (3,700-5,300 trees per ha) on undrained and extensively drained cutovers where ground water table depth (h5) at the beginning of growth period was 1-20 cm. Black alder (Alnus glutinosa) seedlings were most abundant (1,000-1,300 trees per ha) in undrained and extensively drained cutovers on eutrophic peatlands where ground water level at the beginning of growth period is above the soil surface (10 cm) or near it (in the depth of 1-10 cm). Spruce (Picea abies) seedlings were not abundant (averaged 300 ± 101 trees per ha) in these sites. The higher density of spruce seedlings was found (more than 300 trees per ha) in drained cutovers (h5 = 10-80 cm) on mesotrophic peatlands.

It was found that the average density of seedlings of trees in cutovers on fens (eutrophic peatlands) depended significantly on the depth of the ground water table, coverage of ground vegetation and acidity of soils.It was concluded that overly intensive drainage of fens (lowering ground water table at the beginning of the growth period of trees by more than 30-40 cm) created unfavourable conditions for regeneration of trees, decreased the base saturation of soil, increased soil acidity and reduced soil fertility.

Key words: forest regeneration, cutovers, fens, ground water, chemical properties of soils.