One of the oldest trees in the UK has changed its sex. It is an ancient yew tree that surrounds the church of St. Meugan, near the town of Brecon, in Wales.

Throughout its extensive life the tree, more than 16 meters high, has produced small cones, a sign indicating that it is a male plant. Now, however, it has started producing red berries, meaning it is now female.

Ruby Harrison, a spokeswoman for the Woodland Trust, the UK’s largest forest conservation charity, told The Sun that the change “could be a response to stress or a change in environment” of the tree.

This, however, is not the first case of sex change in trees of this species. In 2015, the Fortingall yew, considered the oldest tree of its kind in the UK, went through this similar process.

On that occasion, the 5,000-year-old tree, located in the Perthshire region of Scotland, also began to produce red berries, despite being a male plant until then.

Although the yew phenomenon has been observed before, what made the Perthshire case special was the fact that it was “discovering the process on “such a special tree is what makes this a special story” and The sex change isn’t the amazing bit in this case, it’s the fact it’s this particular tree,” says Dr Max Coleman from the Royal Botanic Gardens.