thumb|Tree of Ténéré (1961)
The Tree of Ténéré (French: ) was a solitary acacia (Vachellia tortilis subsp. raddiana) that was once considered the most isolated tree on Earth. It was a landmark on caravan routes through the Ténéré region of the Sahara Desert in northeast Niger, so well known that it and the Arbre Perdu (Lost Tree) to the north are the only trees to be shown on a map at a scale of 1:4,000,000. The tree is estimated to have existed for approximately 300 years until it was knocked down in 1973 by an allegedly drunk Libyan truck driver.
Background
The Tree of Ténéré was the last of a group of trees that grew along the Azalai when the Sahara desert was less parched than it is today. The tree had stood alone for decades. During the winter of 1938–1939, a well was dug near the tree and it was found that the roots of the tree reached the water table below the surface.
Commander of the Allied Military Mission Michel Lesourd, of the [Central service of Saharan affairs], saw the tree on May 21, 1939:
The French ethnologist and explorer Henri Lhote described his two journeys to the Tree of Ténéré in his book . His first visit was in 1934 on the occasion of the first automobile crossing between Djanet and Agadez. He describes the tree as "an Acacia with a degenerative trunk, sick or ill in aspect. Nevertheless, the tree has nice green leaves, and some yellow flowers". He visited it again 25 years later, on November 26, 1959, with the Berliet-Ténéré mission, but found that it had been badly damaged after a vehicle had collided with it: