El Árbol del Tule is a tree located in the church grounds in the town center of Santa María del Tule in the Mexican state of Oaxaca, approximately 9 km east of the city of Oaxaca on the road to Mitla. It is a Montezuma cypress, or ahuehuete. It has the stoutest trunk of any tree in the world. In 2001 it was placed on a UNESCO tentative list of World Heritage Sites.
In 2005, its trunk had a circumference of 42.0 m , equating to a diameter of 14.05 m , a slight increase from a measurement of 11.42 m m in 1982.
In 1990, it was reported that the tree is slowly dying because its roots have been damaged by water shortages, pollution, and traffic, with 8,000 cars travelling daily on a nearby highway.