Ancient Chuvash Oak, Natural monument in Morgaushsky District, Russia.

The Ancient Chuvash Oak is a very old tree with a wide, gnarled trunk growing in a protected area of Morgaushsky District, in the Chuvash Republic of Russia. It stands in a woodland setting and carries a double official status, recognized both as a natural monument and as a protected area at the national level.

The oak was first documented on 29 June 1966 during a seminar held by the Ministry of Forestry of the Chuvash ASSR. It was declared a natural monument of the Chuvash Republic in 1981 and entered the Register of Old-Age Trees of Russia in 2012. In 2013 experts from the Moscow-based Healthy Forest centre estimated its age at 362 years, counting from 1651.

The Chuvash name Аслӑ Юман means "Great Oak", and the tree was one of the experimental specimens of the Russian forester B. I. Guzovsky. In 2023 it won the national contest "Russian Tree of the Year" with 21,577 votes. It still leafs out and bears acorns every year.

The tree sits in a woodland area where the ground can be uneven, so sturdy footwear makes the walk easier. Visiting in drier months generally means better access, since paths can become muddy and harder to follow after rain.

In 2023 the oak won the Russian Tree of the Year contest with 21,577 votes, making it the country's main tree for that year. It had already been shortlisted in 2013 among the seven best cultural and natural landmarks of Chuvashia.