Subaerial roots promote sedimentation due to their baffling and trapping effects. The density of the aerial roots is crucial in the reduction of current and resultant sedimentation. Mangrove peat formation is dependent on the mangrove type and its position within the tidal zone. Marshes Salt-tolerant grasses and sedges occur in subtropical and temperate coastal zones and may be intermixed with mangroves. Aquatic and semi-aquatic plants inhabit marshes.
Plants occupying marshes are instrumental in accreting sediment by trapping during tidal cycles.
Sediments in marshes generally have a nodular fabric due to sediment-filled stems and bases. Due to a variety of reasons that may include salinity and heat, some coastal areas have no herbaceous or arborescent vegetation. These sites are occupied by non-vascular, lower plant groups that act as traps for sediment. Islands and Barrier Islands Beaches along these geomorphologic structures are sites for accumulations of rafted macrodetritus debris. These may include stems, leaves, fruits and seeds.