A carr, the name of which is derived from the Old Norse kjarr, meaning a swamp, is a type of waterlogged, wooded terrain that, typically, represents a succession stage between the original reedy swamp and the eventual formation of forest in a sub-maritime climate.
The carr is one stage in a so-called hydrosere: the progression of vegetation beginning from a terrain that is submerged by fresh water along a river or lake margin. In sub-maritime regions, it begins with reed-swamp. As the reeds decay, the soil surface eventually rises above the water, creating fens that allow vegetation like sedge to grow. As this progression continues, riparian trees and bushes appear and a carr landscape is created–in effect a wooded fen in a waterlogged terrain. At this stage the pH is not too acidic and the soil is not too deficient in mineral elements. Characteristic trees include alder, willow and sallow.
 See also
- Whittow, John (1984). Dictionary of Physical Geography. London: Penguin, 1984. ISBN 0-14-051094-X.