Rare medicinal tree cultivated in European trials

Five years ago, Jens Peter Skovsgaard collected seeds from yew trees originating from 33 different sites in Europe. The seeds came from trees with good stem form and seemingly strong growth.

From these seeds, which take years to germinate, seedlings have been cultivated in greenhouses at SLU in Alnarp in Sweden. Last year and this year, seedlings have been distributed across Europe, including Sweden, for experimental cultivation. In the basic concept, yew is planted together with oak on fertile soils.

The trials aim to determine how yew can be cultivated. How do the different provenances grow? What stem quality can be achieved? How tolerant is the species to various soils, latitudes, and climates?

Results in 200 years

“Today, we know virtually nothing. The idea is to cultivate yew in multilayered stands with mixed tree species. Yew grows slowly and begins as an understory species,” says Jens Peter Skovsgaard, noting that it will take up to 200 years before forest researchers know how yew actually performs.

“By then, we—or rather our successors—will know much more about how to cultivate yew. These are the time horizons we must work with in forest research.”

European yew forests were heavily exploited during the Middle Ages to supply wood for weapons. Longbows made from yew can be drawn farther than those made from other species, and a volley of arrows from longbows could defeat even armored knights.

Few yew forests left

Today, yew is a rare species in the forest, and it regenerates with difficulty. There are few places where yew forests can be found. In Särö Västerskog in Sweden lies one of Europe’s most beautiful stands, where the trees also exhibit high stem quality.

“For various reasons, yew is very poor at regenerating naturally, and we are poor at utilizing the regeneration that does occur. There are stands of older trees, but almost no young growth. If nothing is done, the yew will disappear in the long term.”

Basis for cancer treatment   

Knowledge of how to cultivate yew is therefore almost nonexistent. At the same time, demand is enormous. Taxol is a chemotherapeutic agent used to treat breast, ovarian, prostate, and lung cancer, and the substance is extracted from yew, which contains high levels of the toxic compound taxine in its needles, bark, branches, and seeds.

“Europe contributes nothing. It comes from North America and Asia. One could imagine a domestic production,” says Jens Peter Skovsgaard.

“Yew is also the highest-priced coniferous timber in Europe. There is potential for niche production for forest owners.”

Facts: Yew

Yew (Taxus baccata) is a native conifer that grows slowly and can become very old. The entire tree is poisonous, except for the red fleshy aril surrounding the seed, which is appreciated by many birds.

The yew reaches a height of 10 to 20 meters. The needles are 1 to 4 cm long, glossy and dark green on the upper side. The bark is brown, soft, thin, and scaly. Yew occurs mainly in southern Sweden (Götaland).