Denmark belongs to the Boreal Kingdom and can be subdivided into two ecoregions: the Atlantic mixed forests and Baltic mixed forests. Almost all of Denmark's primeval temperate forests have been destroyed or fragmented, chiefly for agricultural purposes during the last millennia. The deforestation has created large swaths of heathland and devastating sand drifts. In spite of this, there are several larger second growth woodlands in the country and, in total, 12.9% of the land is now forested. Norway spruce is the most widespread tree (2017); an important tree in the Christmas tree production. Denmark holds a Forest Landscape Integrity Index mean score of 0.5/10, ranking it 171st globally out of 172 countries—behind only San Marino.