The Sundarbans: A Forest Between Tides
Where the forest walks into the sea
Straddling the border of India and Bangladesh, the Sundarbans is the largest contiguous mangrove forest on Earth — a 10,000 km² labyrinth of tidal channels, mudflats and salt-tolerant trees that shields sixty million people from the Bay of Bengal’s cyclones.
A delta in motion
Seen from above, the forest reads as a dark green wedge pressed between the Ganges delta’s silt plumes and the open sea. Every tide redraws its edges: channels migrate, islands surface and dissolve, and the mangroves follow.
The atlas maps this belt as intertidal forested wetlands — one of the rarest functional groups on the planet.
Framed by Bangladesh’s marine boundary, the natural-class view strips away the paddies and ponds: what remains is the coastal fringe — mangrove, marsh and mudflat tracing every channel of the delta.
The mangrove belt, isolated
Filtering the map to the three mangrove functional groups turns the atlas into a single-species portrait: the dark ribbon hugging the coast is all that stands between the delta’s farmland and the bay.
The other side of the levee
North of the forest boundary the classification flips to anthropogenic in a single pixel: rice paddies and shrimp ponds, the delta’s other water world, pressing against the reserve line drawn in 1878.
Reading the pixels
Zoom closer, clamp the elevation band to the first ten metres, and the whole story lives below the tide line: intertidal forest along the channels, brackish marsh on the higher flats, and the sharp line where aquaculture replaces it all.
Swipe it yourself
Drag the divider: satellite imagery on the left, the atlas classification on the right — same framing, two ways of seeing the same forest.
Why it matters
Mangroves store three to four times more carbon per hectare than tropical rainforest, and the Sundarbans alone buffers storm surge for one of the most densely populated coastlines in the world. Watching this forest change, pixel by pixel, is watching the front line of coastal adaptation.
Last updated20 July 2026
6/10
Realms
10/25
Biomes
22/110
Ecosystems
22/110
Ecosystems
Area890,469 km²
Population68,720,337
Population Density126.86/km²
Tropical rainforest, Daintree, northeast Australia
© David Keith
Description
A huge diversity of species occupy niches within a complex vertically-layered structure of plant forms. High productivity is fuelled by rapid-growing plants including buttressed trees, bamboos, epiphytes, lianas and ferns. Forest canopies sustain moist soils and abundant leaf litter decomposed by fungi and bacteria. High diversity of invertebrates at all levels of the forest supports diverse vertebrate life forms, particularly mammals and birds, which play critical roles in plant dispersal and pollination. Conditions near the equator are stable and humid year-round (up to 6000 mm rain per annum), but become more seasonal with mild winter frosts in the subtropics.