A
carr 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 name derives from the Old Norse
kjarr, meaning a swamp. The carr is one stage in a
hydrosere: the progression of vegetation beginning from a terrain 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 such as
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.