Freshwater habitats include rivers, streams, lakes, ponds, marshes and bogs. When peat accumulates, bogs and fens arise. The boreal forest also has vast areas of wetland, particularly bogs and fens. The polar forests are low and are mixed with swamps, lichens, bogs and shrubs. They live in the Mud Kingdom, which consists of marshes, swamps, and bogs. They occur in several variants&colon; raised bogs, soligenic bogs and blanket bog. Gleysols and peat bogs occupy poorly drained areas. They created the large Long Meadow out of hilly upland pasture interspersed with peat bogs. "Sarracenia" tend to inhabit fens, herb bogs, and seasonally wet grasslands. Surveyors and construction crews had to maneuver through swamps, bogs, and tamarack forests. This area is a patchwork of alpine heaths, herbfields, feldmarks, bogs and fens. The tundra is covered in marshes, lakes, bogs and streams during the warm months. Ireland possesses almost of actively growing bogs and fens. The resulting stagnant water is conducive to the formation of bogs and fens. They include lakes and ponds, rivers, streams, springs, bogs, and wetlands.