The collective term 'Wet Woods' is given to both bog woodlands and floodplain woods because they are both characterised by a close dependence on hydrological systems, which influence their development, structure and diversity.

Bog woodland sites are found on wet peat mires where the high level of the water table and the naturally low fertility of the peat restricts the growth of the trees. In Scotland, they would normally form part of mosaic of natural forest types found within the wider Caledonian forest habitat.

Floodplain woods are the natural tree communities of the wetlands and low-lying terraces of river systems.