%0 Research Notes
%T Impact of birch crop density and heigth equalization of Norway spruce understorey on spruce seedlings' height growth on a drained peatland
%A Päätalo, Marja-Leena
%A Hilli, Anu
%A Moilanen, Mikko
%A Tillman-Sutela, Eila
%D 2003
%J Suo - Mires and peat
%V 54
%N 3
%U http://suo.fi/article/9829
%X A viable understorey of Norway spruce often develops under a nurse crop on nutrientrich
peatlands drained for forestry. The impact of birch nurse crop density and height
equalization of the Norway spruce understorey on the height growth of spruce seedlings
was studied on three sites: on a transforming herbrich spruce swamp, an abandoned
peat field and a mixed peat/mineral soil field. The nurse crop was managed in
1990: 1) no thinning, 4000 stems ha-1, 2) thinning to 1000 stems ha-1. 3) thinning to
500 stems ha-1, or 4) removal of the nurse crop. In addition, the spruce seedlings over
1 m in height were removed from randomized halves of each plot. The unmanaged
nurse crop reduced the growth of the understorey the most on all the sites. On the other
hand, the spruce seedlings grew the best on the plots where the nurse crop had been
removed. Due to height equalization the growth of the spruce understorey first slowed
down, but towards the end of the study period the height growth of the equalized and
non-equalized spruce understoreys were almost the same.