The juniper groves of Spanish juniper ("Juniperus thurifera") constitute a curious formation that occupies the high heaths and "mesetas" of the interior, nearly always above 900 metres in altitude. The principal woodlands of this type are in the Serranía de Cuenca, Sistema Ibérico, Alcarria, Maestrazgo and other mountains of the interior. They do not usually form dense forests, but rather parkland or small woods in meadows. They prefer soils developed over limestone, especially those of an ochre or reddish color and rich in clay, "de carácter relicto (Terra rosa, Terra fusca);" on occasions, as in the region of Tamajón (Guadalajara), they also colonize siliceous terrain.