The landscape is covered mostly by coniferous taiga forests and fens, with little cultivated land. Of the total area 10% is lakes, rivers and ponds, and 78% forest. The forest consists of pine, spruce, birch, and other species. Finland is the largest producer of wood in Europe and among the largest in the world. The most common type of rock is granite. It is a ubiquitous part of the scenery, visible wherever there is no soil cover. Moraine or till is the most common type of soil, covered by a thin layer of humus of biological origin. Podzol profile development is seen in most forest soils except where drainage is poor. Gleysols and peat bogs occupy poorly drained areas.