Dhaka, Nov. 6 -- On the ragged edge of the Sundarbans, where the forest meets the brackish tides, Islam Sana from Tetultala Char in Maheshwaripur Union of Khulna's Koyra Upazila counts change by what is missing. "Five or six years ago this was dense Sundari," he says, pointing into a thinning stand. "Now it's almost bare."

For 40 years, the Koyra fisherman-forager's life has orbited the mangrove's rhythms, flood and ebb, blossom and bee, but the rhythm is off. "Many Sundari have dried up," he says.

The irony is painful.

The Sundarbans, the world's largest mangrove forest, owes its name to the abundance of the Sundari tree. But rising soil salinity and an abnormal spread of parasitic vines have put the species under existential threat....