sentences:  Situated on a plateau surrounded by mountains, Aouderas expanded in the 19th and 20th centuries.In the 1970s, French geographers estimated there were 15000 date palms in Aouderas, more than the other older date plantations in In Gall, but half the number of the newer plantations at Telwa and Timia to the north.As of 1972, the number of farms expanded since Heinrich Barth's visit in 1850, and the number of hectares under cultivation has expanded from 19.5 in 1946 to 59.3.