Thirteen years after his first visit, wildlife biologist Reza Khan returned to Adampur Reserved Forest in Moulvibazar as part of a survey to update Bangladesh's Faunal Red List. The gibbons still called from the canopy and the dwarf kingfishers still haunted the forest streams, but one quiet absence, the near disappearance of the forest's once abundant tree ferns, hinted at a slower, harder-to-notice kind of change.