The science bit
Evergreen tree up to 25m tall; crown becoming domed with age. Bark smooth, brown tinged with purple, falling off in plates. Shoots spreading or ascending, covered in green leaf bases. Leaves up to 4cm long; linear, glossy and dark green; spirally arranged. Male cones approximately 4mm in diameter and spherical. Fruit appearing on undersides of one-year-old shoots; distinctive scarlet-red aril extends beyond the seed. Pollinated by wind.
- Yew is extraordinarily long-lived and slow-growing, with some trees estimated to be over 3,000 years old.
- The Romans believed yew grew in hell, the Norse and Celt peoples thought it protected against bewitchment and death and it's often seen in churchyards as Christians believed its poison protected the dead.
Where it grows
Yew is native to area stretching from central Europe to the Caucasus. It can grow in a wide range of conditions: it is extremely tolerant of temperature, humidity and extremes of acid or alkaline soil; however, it does not grow well in soil that has been compacted by vehicles.
One of the world's oldest wooden artifacts is made from yew: a spearhead found in Essex, UK, dated at 450,000 years old.
Yew wood is extremely hard-wearing and was used in the Middle Ages to make the traditional English longbow: a weapon that helped the English win famous battles against the French, such as Agincourt in 1415.
More recently a chemical found in yew, called taxol, has been found to have anti-cancer effects. They have since been synthesised and are now being used in the treatment of breast, ovarian and lung cancers.
English yew (Taxus baccata) is reasonably common in the UK and other countries in Western Europe, but the North American Pacific yew (Taxus brevifolia) is now rated ‘near threatened’ on the International Union for Conservation of Nature’s Red List. Its high taxol content has led to over-harvesting for use in anti-cancer treatments.
The seeds are dispersed by birds, which are attracted by the bright red, sweet and juicy aril. The seed has a tough coat, which needs the digestive system of birds to weaken it to enable the seed to sprout.
The majority of this tree is highly poisonous, even the dead and dried leaves, so farmers need to ensure that their livestock does not graze too close to yews.
- Aril: partial seed covering.
- Crown: cluster of leaves and branches at the top of trunk.