Nature · Earth Science
Forests that root in water
Mangroves and swamps are wetland forests — places where trees grow with their roots in water for much or all of the year. Straddling the boundary of land and sea, or drowning inland basins, these waterlogged forests teem with life, guard coastlines from storms, and store carbon at rates few other ecosystems can match.
Where sediment collects in sheltered, waterlogged ground — along tropical coasts, in river backwaters or in poorly drained basins — specially adapted trees take hold. Mangroves tolerate salt and tides with stilt roots and breathing roots; freshwater swamp trees endure months of flooding.
Stilt and breathing roots anchor trees in tidal mud, trapping sediment and sheltering a nursery of marine life.
Salt-tolerant trees of the tidal coast
Mangroves are the only trees that thrive in salt water, gripping tidal mud with arching stilt roots and drawing air through snorkel-like roots. Their root maze shelters countless young fish.
Flooded forests of the lowlands
Freshwater swamps are forests that stand in still or slow-moving water for much of the year. Cypress and other specialists grow flared trunks and “knees” to survive the flooding.
Treeless wetlands of grass and reed
Marshes are wetlands ruled by soft-stemmed plants — reeds, rushes and grasses — rather than trees. Salt marshes fringe estuaries, while freshwater marshes teem with waterfowl.
Waterlogged stores of ancient carbon
In cool, waterlogged ground, dead plants decay so slowly they pile up as peat. Bogs and fens lock away immense stores of carbon and preserve pollen — and sometimes bodies — for millennia.