TIME-SCALE FOR FOREST REGROWTH - ABANDONED GRAZING AND AGRICULTURAL AREAS IN SOUTHERN NORWAY

The purpose of the paper is to demonstrate how rapidly abandoned agric ultural and grazing land becomes naturally forested. The study was car ried out in The Romerike Landscape Protection Area in southern Norway. The area is a ravine landscape in a southern boreal vegetation region used for agricultural production and grazing of domestic animals for several hundred years. When agriculture was mechanized and single-prod uct specialization was introduced about 1950, the area was gradually a bandoned as agricultural land and lay open for regrowth as a forest ec osystem. The open areas, previously used for grazing, decreased by clo se to 50%, with an increase in areas covered by shrubs and forest, mai nly grey alder. Succession rate of regrowth depended upon distance to forest edge and vegetation type with slower regrowth in wet areas at t he bottom of the ravines compared to the dryer areas. The consequences of changes in land use are less diverse communities and a reduction i n the length of ecotones between, e.g. forest and open land. The regro wth with forest could reduce the diversity of flora and fauna in the l ong term.