Taxus baccata

Taxus baccata, an evergreen tree from the Taxaceae family, is the original yew tree. To set it apart from related species, it's also called common yew, European yew, or, in North America, English yew. Its native range spans much of Eurasia and Northwest Africa, where it grows as a woodland tree. Every part of the plant except the fleshy aril is poisonous; these toxins can enter the body through inhalation, ingestion, or skin contact. The wood has long been prized for crafting longbows and musical instruments like lutes. Yews are commonly grown as ornamentals, hedges, or topiaries, and are frequently planted in churchyards, where some trees reach remarkable ages. Many explanations exist for this tradition, particularly the yew's links to death, immortality, and rebirth. Some place names derive from the Proto-Celtic *eburos, though scholars disagree on whether this word referred to the yew tree.

Carl Linnaeus first described the species Taxus baccata in 1753 in his Species Plantarum, and the name remains accepted despite 108 synonyms from later taxonomists. Linnaeus chose the genus name Taxus, possibly from the Greek toxon, meaning bow. The word "yew" comes from Old English, ultimately tracing back to Proto-Indo-European *h₁eyHw- through Proto-Germanic *iwo, which also produced Celtic forms like Old Irish ēo and Welsh. Baccata is Latin for "bearing berries."

Yews are small to medium-sized evergreens, growing up to exceptional heights and trunk diameters. Their bark is thin, scaly, reddish-brown, and flakes off in small pieces aligned with the stem. The flat, dark green leaves are arranged spirally on the stem, but their bases twist to align the leaves in two flat rows on either side, except on erect leading shoots where the spiral is more obvious. The seed cones are modified, each holding a single seed nearly surrounded by a fleshy scale that develops into a soft, bright red, berry-like aril. This aril is open at the end and matures 6 to 9 months after pollination. It is gelatinous and very sweet. Male cones are globose and shed pollen in early spring. Yews are mostly dioecious, with male and female cones on separate trees, but occasional individuals can be variably monoecious or change sex over time.

The yew is native to every European country except Iceland, the Caucasus, and from Turkey east to northern Iran. Its range extends south to Morocco and Algeria in North Africa, and into parts of Southwest and South Asia. A few populations exist on the Azores and Madeira. Its northern limit in Scandinavia is set by frost sensitivity, and global warming is predicted to allow it to spread inland. It has been introduced elsewhere, including the United States. In central Europe, the richest populations are in Swiss yew-beech woodlands on cool, steep marl slopes. In the UK, it grows best on steep chalk slopes, forming extensive stands that invade grassland outside beech woods. In more continental climates, it thrives in mixed coniferous and broadleaf forests. Under its evergreen shade, no other plants can grow.

The species prefers steep, rocky, calcareous slopes. It rarely develops beyond saplings on acid soil under a forest canopy, but tolerates a wide range of soil pH when planted by humans, as in churchyards and cemeteries, where some of the largest and oldest trees in northwestern Europe are found. It grows well in well-drained soils, tolerating nearly any type, typically humus and base-rich soils, but also rendzina and sand soils with adequate moisture. It can survive temporary flooding and moderate droughts. Its roots can penetrate extremely compressed soils, such as on rocky terrain and vertical cliffs. It normally appears singly or in small groups in the understory, but forms stands in sheltered calcareous sites. It is extremely shade-tolerant and has the widest temperature range for photosynthesis among European trees, able to photosynthesize in winter after deciduous trees have shed their leaves. It can grow under partial canopies of beech and other deciduous trees, though it only becomes large without such shade. Birds eat the arils and disperse the hard seeds undamaged in their droppings. Despite the toxins, some birds like hawfinches, greenfinches, and great tits extract and eat the kernels.

Historically, yew populations were gravely threatened by felling for longbows and destruction to protect livestock from poisoning. It is now endangered in parts of its range due to intensive land use. The species is also harvested for pharmaceutical demand for taxanes. Trees are often damaged by browsing and bark stripping. Its thin bark makes it vulnerable to fire. Its toxicity protects against many insects, but the yew mite causes significant bud mortality, and fungi can kill seedlings. Clippings from ancient UK specimens, including the Fortingall Yew, were taken to the Royal Botanic Gardens in Edinburgh to form a mile-long hedge. This "Yew Conservation Hedge Project" aims to maintain the DNA of Taxus baccata. In the early 2010s, a conservation program in Catalonia, run by the Forest Sciences Centre of Catalonia, worked to protect genetically endemic yew populations from overgrazing and forest fires.