5,000-year-old Fortingall Yew amazed scientists with sex shift, although the millennia-old yew has been recorded to harbor a female branch before.
Among the oldest trees of Europe, the Fortingall Yew silently bears witness to the history of its birthplace – Fortingall, Perthshire, Scotland. Legends surround the yew in an aura of mysticism and mystery. For residents of the small Scottish village, the millennia-old yew is a revered landmark.
For scientists it is an object of study offering a new cause for excitement. For centuries the 5,000-year-old Fortingall Yew has been recorded to be a male tree. Now, Doctor Max Coleman with the Royal Botanic Garden Edinburgh has observed an interesting change. A sex shift is occurring with one branch of the tree. What sparks this shift in a male tree of this age is the question underpinning scientists’ efforts.
Typically, male yew trees produce small rounded pockets filled with pollen that is then released in the air. Female yew trees produce brightly coloured red berries hanging from the branches. The 5,000-year-old Fortingall Yew amazed scientists with sex shift when one of the branches was observed to be producing the red berries, in stark contrast with the rest of the tree.
Nonetheless, sex changes are not uncommon with some tree species, including yews. Ash trees change sex routinely. Yew trees are rarely observed to shift sex. And what makes this finding so spectacular is the fact that for centuries, the Fortingall Yew has been recorded to be male. The shift in this case may be due to maximizing the chances of reproduction and thus survival.
Scientists are looking on whether age or environmental factors may have pushed the Scottish yew to change sex. And only with one branch.
Yew trees are rarely observed to shift sex. Typically, they are dioecious. In rare cases, hormones may trigger a total shift. Partial shifts are a very rare phenomenon. However, with the Fortingall Yew, Coleman explained that in 1996 it was observed to have produced red berries on one branch.
According to the record, it would be the same branch noticed recently. Thus, it’s possible that the same branch has turned female and remained as such for the past two decades. The Fortingall Yew is healthy and will probably live many more centuries. Starting now, botanists will keep a permanent record of observations on both its male and female traits.
Photo Credits: geograph.org.uk