Editing Fen (section)

=== ''The Biology of Peatlands'' (Rydin) definition ===
In ''The Biology of Peatlands'' fens are defined by the following criteria:<ref name=":62"/>

# The wetland is not flooded by lake or stream water.
# Woody vegetation 2 meters or taller is absent or canopy cover is less than 25%.
# The wetland is [[minerotrophic]] (it receives its nutrients from mineral-rich groundwater).

A further distinction is made between open and wooded fens, where open fens have canopy cover less than 10% and wooded fens have 10–25% canopy cover. If tall shrubs or trees dominate, the wetland is instead classified as a wooded bog or [[Freshwater swamp forest|swamp forest]], depending on other criteria.