Palms are uniquely tropical trees. Only one or two species are able to survive a frost, so their range is restricted mostly to the tropics. Palms are more closely related to grasses and orchids than they are to other kinds of trees. The Amazon provides them with a perfect environment and is a biodiversity hotspotover 900 species of palm trees are known, and many of them are used in multiple ways by the local people. Many palm fruits are edible, and other species provide materials for roofing and other construction, or for fiber. A native-built dwelling relies on the use of at least three or four palm species. The dart quiver of a blowgun is also made from palm leaves.