Tree 7: Common Yew
The Yew is exceptionally long-lived, able to live for thousands of years. Some authorities claim they have the potential to live indefinitely. The UK has most of the World’s ancient Yews; they are the oldest living feature in our landscape.
After around 900 years, when Yews enter their ‘ancient’ phase, their trunks gradually hollow out. So, instead of the traditional ring counting method, age is gauged by measuring girth: one metre of girth equals about 100 hundred years. The Fortingall Yew in Perthshire is estimated to be 5000 years old.
Ancient Yews regenerate when branches droop to the ground, take root and form new stems linked to the ancient trunk. The crowns of ancient Yews can be described as pulsating, growing outwards, then reducing via dieback and large branch failure, followed by further outward growth.
Another peculiar biological survival strategy for ancient Yews is that new roots grow down into the hollow from the surrounding bark. These internal roots thicken and unite, building new stems within the ‘shell’ of the original stem.
Yews have long been considered symbols of everlasting life because of their extraordinary longevity. They were important in Celtic and pre-Christian sacred places and most of our ancient Yews are in churchyards and monasteries. Their very poisonous bark, leaves and seeds provide another connection to rituals of death.
In March/April, on the underside of the leaf, the tiny green female flowers gradually turn brown. Yews do not have cones: each seed is enclosed in a red, fleshy, berry-like structure known as an aril, open at the tip. Flowers on a male tree are like tiny round yellow blobs. If it is windy you may see them release their smoke-like pollen.
The dense growth and cracks, hollows and niches of ancient Yews provide protection and shelter for birds, and insects all year round, Various birds and small mammals eat the fruits, as do the caterpillars of the satin beauty moth.
Yews are useful as windbreaks, for hedging and for topiary. Yew clippings are used to produce the chemotherapy drug ‘Taxotere’. Its fine grained wood ranges in colour from cream to deep orange/red – suitable for cabinet making, veneers and inlays. The English Archers at Agincourt relied on Yew’s strength and elasticity for their bows.