A string bog has a pattern of narrow (2–3m wide), low (<1m high) ridges oriented at right angles to the direction of drainage with wet depressions or pools occurring between the ridges. The water and peat are very low in nutrients because the water has been derived from other ombrotrophic wetlands. The peat thickness is >1m.
Known as Aappamoore in Finland and Strangemoore in other parts of Northern Europe, string bogs are features associated with periglacial climates, where the temperature results in long peiods of subzero temperatures. The active layer exists as frozen ground for long periods and melts in the spring thaw. Such slow melting results in characteristic mass movement processes and features exclusively associated with specific periglacial environments.