This amazing oak stands at Les Rues Éon, just outside Concoret, beside the road towards Tréhorenteuc. Its twisted, hollow trunk and enormous dimensions make it one of the most striking trees in the Brocéliande area; nearby, the forest contains other celebrated veteran trees such as the Chêne des Hindrés and the Hêtre de Ponthus. The tree was formerly known as the Chêne des Rues Éon and became known as the Chêne à Guillotin from the 1970s onward.
Highlights and Activities
The Chêne à Guillotin is a living natural monument. It is a pedunculate oak (Quercus robur) with a circumference of approximately 9.6 metres and a height of about 15–20 metres, although published measurements vary. Its trunk has been hollow for centuries, making conventional tree-ring dating impossible and contributing to uncertainty over its exact age. Local tourism sources traditionally describe it as around 1,000 years old, while the Morbihan inventory has given a more conservative estimate of about 500 years.
The tree has required active conservation. The municipality acquired the site around 2000 and the Office national des forêts (ONF) subsequently worked on its protection. A wooden structure was installed to reduce damage from visitors but was removed in 2019 after concerns about the tree's health. Visitors can now see the oak from behind a protective barrier and are asked not to approach or touch it.
Legends, folklore and myths
The best-known story concerns Pierre-Paul Guillotin, a refractory priest from Concoret during the French Revolution. According to the later local tradition, he hid inside the hollow oak while being pursued by Republican soldiers. A spider's web supposedly concealed the entrance, causing the soldiers to conclude that nobody could recently have entered the tree. Some versions say that the spider was sent or assisted by Notre-Dame de Paimpont. However, historical research shows that the story's connection with this particular oak developed relatively late: the first literary mention of the tree dates to 1896, while the explicit identification of the oak as Guillotin's refuge appears in tourism literature from 1979 and subsequent local folklore publications. A second tradition connects the oak with Éon de l'Étoile, the 12th-century religious dissenter whose name survives in Les Rues Éon. The oak was formerly called the Chêne des Rues Éon, and later folklore associated it with a supposed treasure of Éon. The tree has also acquired a healing tradition: local folklore has regarded the oak as a source of strength, with sick people traditionally seeking its supposed restorative power.
Accessibility and Visitor Information
The Chêne à Guillotin is reached from the road between Concoret and Tréhorenteuc, on the D141. A visitor parking area and picnic area are located approximately 100 metres from the tree; the final approach is on foot. Because the tree is fragile and branches may fall, visitors must remain behind the protective barrier and must not touch or climb the oak. More broadly, visitors using the surrounding Brocéliande forest should follow marked routes and respect temporary access restrictions.