Boxhohn-Eiche, Ancient oak tree in Troisdorf, Germany.

The Boxhohn-Eiche was a pedunculate oak tree that stood between Altenrath and Hasbach and shaped the landscape of the Wahner Heide region. Over time it developed a hollow trunk and was noted in the area for its size and age.

The pedunculate oak was named after the Boxhohn hamlet, abandoned in 1915 when the Wahn shooting range was enlarged. It was long called the "1000-year-old oak", though it certainly never reached that age. In January 2019 it fell, probably also because of the very dry summer of 2018; the dead wood is left to rot on the spot.

The oak's name comes from the Boxhohn hamlet, abandoned in 1915 when the Wahn firing range was enlarged. A pedunculate oak was planted beside the rotting remains on 23 March 2019, chosen because it copes better with summer heat and prolonged drought.

The site can be reached via a service road that branches east from Hasbacher Street and leads to the location. A young oak was planted here in 2019 to continue the tradition.

In the 1930s engineers reinforced the already hollow wood with a concrete core and iron rails to stabilize its structure. This intervention allowed the tree to stand for many more decades before its condition finally became untenable.