Yew

In Greece, it is a relatively rare species with a sporadic appearance. In Paggaio, it is found in the Sub-Mediterranean and mountainous zone between 800 and 1,300 m asl., on moderate slopes. Old trees are found in the ravine southwest of Paleochori, in the ravines of Nikisiani, and individuals sporadically on the mountain ridge from the forest village to the sub-alpine meadows. In Greece, its fragmented population is the main cause of its collapse, followed by the illegal logging of mature individuals. Its reduced ability to absorb light, compared to other coexisting species, and its extinction in the past by livestock breeders, are some of the reasons that led to its shrinkage or disappearance from several sites. Nowadays, seeing a yew it is considered a great privilege.

Evergreen tree, 10-15 m high. Its leaves are needle-like, soft and flat, deep green above and light green below (they look like fir needles). The reproductive organs of the flowers are located in separate trees, i.e., they have only male or only female flowers. Its fruit consists of a seed surrounded by a fleshy red shell. Although all parts of the plant contain toxic alkaloids and their consumption by animals causes death, the red shell of the fruit is tasty and nutritious, but not toxic. In this way, color is used for luring birds, exchanging a nutritious meal with easy seed transportation, while at the same time making the consumption of the toxic seed contained in the embryo prohibitive. Yew is the most shade-tolerant forest tree of the Greek flora. It is characterized by slow growth, longevity and tolerance to air pollution. It is considered vulnerable to climate change. It is a poisonous tree, mentioned by Theophrastus and Dioscorides. The Latin name “Taxus” has a common root with “toxic”. In recent decades, biochemists have discovered that the bark of the American yew contains taxol, a substance that has been shown to be particularly effective in fighting cancers, such as breast and ovarian cancers. The result of this discovery was a huge demand from the pharmaceutical companies and for this reason thousands of mature trees were killed due to cutting or removal of their bark. To treat breast and ovarian cancer in the United States alone, 360,000 trees would be needed each year, which would lead to the species’ extinction in a few years. The solution was given by the discovery of a similar substance in the leaves of the European yew, a species similar to the trees of Paggaio. The leaves are “useable” organs of the plant, as they are renewed. Today, the substance is produced in leaf cell cultures on an industrial scale, then undergoing the necessary chemical modification.

Due to the small number of individuals occurring in Paggaio and its limited geographical distribution, the species is considered quite endangered. Logging and road construction in sites with yew could lead to its complete disappearance from Paggaio.

Least Concern.

Yew belongs is assigned to the “LC-Least Concern” category by IUCN, which does not necessarily mean that the species is safe or should not be protected. It rather means that the species “is not in immediate danger of extinction if the current conditions are maintained”. Although in Greece yew occurs in small numbers and in small, scattered populations, it is not subject to a special protection regime. A potential threat is the overexploitation of the plant for its medicinal (anti-cancer) properties. In the Mediterranean, yew forests belong to the habitats 9580 “Mediterranean forests with Taxus baccata” and 9210 “Apennine beech forests with Taxus and Ilex“, and due to their rare occurrence are designated as priority habitats.