Urban Rainforest On the west side of the island of Manhattan in New York City, tree by tree, leaf by leaf, a 2,500 square foot sector of the Central African Republic's Dzanga Ndoki Rainforest has been transported to, or recreated at, the American Museum of Natural History's new hall of biodiversity. When the hall opens this May, visitors will visit one of the world's biggest and most accurate reproduction of one of nature's most threatened creations. To bring the rainforest to New York, a team of nearly two dozen scientists — the largest collecting expedition the museum has ever organized for an exhibit — spent five weeks in the African rainforest collecting soil, plants, and leaves: recording and documenting species studying trees shooting videotape and still photos: and interviewing local people. 'This area has been explored very little,' says Hoel Cracraft who estimates that the museum will eventually collect 150 to 180 mammals, more than 300 species of birds, hundreds of butterflies, and hundreds of thousands, if not millions, of organisms. The exhibition may even have produced a special prize — scientists suspect they have uncovered several new species. To give the forest a sense of realness, the back wall of the exhibit is an enormous ,video screen, sounds will come out from hidden speakers, and plans even call for forest smells. Computer controls will vary the effects so that no two walkthroughs will ever be exactly the same. After the team returned to New York, the forest was reproduced with the help of the computer. Computer Modelling programmes plotted distances and special relationships. Artists studied photos and brought what they saw to life. Plaster trees were made. Recreated animals began to stand in the rainforest of the hall. Flying creatures will hang from the ceiling. The light in the forest — one of the exhibit's cleverest re-creations — will seem real. Long tube lights will have the correct colour and temperature to produce a natural effect. The plants and animals exhibited throughout the hall exist naturally in a perfect balance — remove one, and the whole is imperfect if not endangered. The exhibit is proof to the hope that the world's rainforests will never exist solely as a carefully preserved artifact. What is this passage mainly about?