3Regeneration under shelterwood- control of environmental factors

The objectives of this work were to quantify the effects of stand stem density (SSD), orientation and distance with respect to shelter tree, and fertilisation on the establish-ment of Pinus sylvestris L. and Picea abies (L.) Karst. regenerated by direct seeding and planting at different soil preparations. The field experiments were performed on South (64°14ʼN, 19°46ʼE, 225 m a.s.l.) and North (64°09ʼN, 19°36ʼE, 274 m a.s.l.) slopes in boreal Sweden. Regeneration and early growth in three stand stem densities (SSDʼs) with different light regimes, i.e. uncut forest (~500 stems/ha), shelterwood (~150 stems/ha), and clear-cut, were compared. Sowing, after using two soil preparations (mineral soil and a mixture of mineral soil and humus layer ground to a fine texture), and planting were done in 2001 at six distances in north-south direction from trees (0.5, 1, 1.5, 2, 4 and 6 meters). Naturally regenerated P. abies seedling and saplings were also selected in pairs in the uncut forest. Half of all seedlings and saplings in the experiments were irrigated with fertiliser (10mM N). The light environment didnʼt differ significantly between different orientations or distances with respect to trees, but it was clearly different between SSDʼs. On the Nort