A picture of Mecca decorated one of her walls but Ms. Rokima, who also goes by one name, said she had no idea what the photograph, a gift from a local official, meant. “I had my own gods in the forest but I cannot go back to the forest because there is no forest left anymore,” she said, of her birthplace by a river.

Even Mr. Rahmat, Mr. Tarip’s son-in-law, admitted his own wife was an imperfect convert. She maintains a preference for wild pig, a forbidden meat in Islam. Mohammed Asrul, a transmigrasi village chief from Nyogan village in Jambi, is also married to an Orang Rimba woman. More forest people should follow his wife’s path, he said. “They will only make progress if they marry outsiders,” he said.

To survive on the outside, Mr. Tarip has planted rubber and oil palm on some of his customary land, which he owns because of his indigenous status, even though he knows the crop is responsible for destroying his old way of life.

The tenacious root structures of the African oil palm make it hard for other plants to flourish, even after the crop cycle is done. Pesticides used to maintain the plantations despoil rivers, even as they have contributed to a product that feeds a global hunger for cheap snacks, cosmetics and biofuel. Worst of all, oil palms, with their blood-red fruit, do not produce colorful blooms.

“The gods like fancy flowers,” Mr. Tarip said. “They are angry when no one brings them flowers.”