Vegetation survey data from the LTER study site at Birkenes (LTER_EU_NO_003) between the years 1991 and 2013. The percentage cover of every vascular plant and moss species was determined in (up to 50) permanently marked 1 m² plots (41 plots 1991, 50 plots 1998, 2003, 2008, 2013), all plots positioned within a 0.2 ha area (50 m x 40 m) of bilberry dominated spruce forest.