Pocosin is the name for a form of swampy wetlands or bogs found in North America with deep, acidic, sandy and peaty soils. The word pocosin is likely borrowed from the Eastern Algonquin language family .
Occurrence and soil
Pocosine occur in the Atlantic coastal plain of North America (which stretches from Florida to Delaware ), there especially on poorly drained heights between flowing waters or floodplains . The soil of pocosines is saturated by groundwater , apart from short seasonal dry phases or after long periods of drought . Pocosin soils are nutrient deficient (they are oligotrophic ), especially in terms of phosphorus . Rising groundwater ensures regular flooding. Pocosine often lie above so-called floating groundwater levels above damming, impermeable soil layers.
Pocosins are often characterized by shrub-like vegetation. They are therefore sometimes referred to as' "shrub bogs". Pinus serotina dominates among the tree species that occur , but the frankincense pine and the swamp pine can also be associated with pocosin.
Sometimes a distinction is made between "short pocosins" (with short-growing trees, deep peat and low soil nutrients) and "tall pocosins" (the latter with larger trees, shallower peat layers and higher nutrient content). As the frequency of complete water saturation decreases and the thickness of the peat horizon decreases, pocosine changes into a pine-dominated forest type (so-called "flatwoods"). A broader definition of "pocosin" includes all bog areas with shrubs or trees in the Atlantic coastal plain of North America, as well as locations with Chamaecyparis thyoides and frankincense pine. A narrower definition restricts Pocosine to shrubby "short pocosins" and "tall pocosins" with Pinus serotina .
Adaptation to fire
Pocosin ecosystems are adapted to regular fires . As a so-called pyrophyte, Pinus serotina only releases the seeds from the cones when a suitable germination bed has been created by fire. Forest fires in Pocosinen can be very intense and sometimes burn themselves deep into the peat layer, ultimately leading to the formation of small lakes and ponds.
If forest fires occur about once a decade, Pinus serotina is favored and often the dominant tree species, while reeds (genus Arundinaria ) are promoted in the undergrowth compared to bushes. More frequent fires lead to a shrubby undergrowth characterized by pyrophytes. Annual fires prevent the growth of shrubs and reduce the coverage by Pinus serotina , so that a temporarily flooded savannah with sweet and sour grasses and an herbaceous lower layer is created.