NEWS - Yew - tree of the year 2013

Yew - tree of the year 2013

Description

It is a small- to medium-sized evergreen tree, growing 10–20 metres tall, with a trunk up to 2 metres diameter. The bark is thin, scaly brown, coming off in small flakes aligned with the stem. The leaves are lanceolate, flat, dark green, 1–4 centimetres long and 2–3 millimetres broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flat rows either side of the stem, except on erect leading shoots where the spiral arrangement is more obvious. The leaves are highly poisonous.

The seed cones are highly modified, each cone containing a single seed 4–7 millimetres long partly surrounded by a modified scale which develops into a soft, bright red berry-like structure called an aril, 8–15 millimetres long and wide and open at the end. The arils are mature 6–9 months after pollination, and with the seed contained are eaten by thrushes, waxwings and other birds, which disperse the hard seeds undamaged in their droppings; maturation of the arils is spread over 2–3 months, increasing the chances of successful seed dispersal. The seeds themselves are extremely poisonous and bitter, but are opened and eaten by some bird species including Hawfinches and Great Tits.The aril is not poisonous, and is gelatinous and very sweet tasting. The male cones are globose, 3–6 millimetres diameter, and shed their pollen in early spring. It is mostly dioecious, but occasional individuals can be variably monoecious, or change sex with time.

Longevity

It is relatively slow growing, and can be very long-lived, with the maximum recorded trunk diameter of 4 metres probably only being reached in about 2,000 years. The potential age of yews is impossible to determine accurately and is subject to much dispute. There is rarely any wood as old as the entire tree, while the boughs themselves often hollow with age, making ring counts impossible. There are claims as high as 5,000-9,500 years, but other evidence based on growth rates and archaeological work of surrounding structures suggests the oldest trees are more likely to be in the range of 2,000 years. Even with this lower estimate, Taxus baccata is the longest-living plant in Europe. One characteristic contributing to its longevity is that it is able to split under the weight of advanced growth without succumbing to disease in the fracture, as do most other trees.

Uses and traditions

One of the world's oldest surviving wooden artifacts is a Clactonian yew spear head, found in 1911 at Clacton-on-sea, in Essex, UK. It is estimated to be between 424,000 and 374,000 years old.

In the ancient Celtic world, the yew tree (*eburos) had extraordinary importance; a passage by Caesar narrates that Catuvolcus, chief of the Eburones poisoned himself with yew rather than submit to Rome (Gallic Wars 6: 31). Similarly, Florus notes that when the Cantabrians were under siege by the legate Gaius Furnius in 22 BC, most of them took their lives either by the sword or by fire or by a poison extracted ex arboribus taxeis, that is, from the yew tree (2: 33, 50-51). In a similar way, Orosius notes that when the Astures were besieged at Mons Medullius, they preferred to die by their own swords or by the yew tree poison rather than surrender.

Longbows

The oldest surviving yew longbow was found at Rotten Bottom in Dumfries and Galloway,Scotland.It has been given a calibrated radiocarbon date of 4040 BC to 3640 BC and is on display in The National Museum of Scotland. Yew is also associated with Wales and England because of the longbow, an early weapon of war developed in northern Europe, and as the English longbow the basis for a medieval tactical system. Yew is the wood of choice for longbow making; the bows are constructed so that the heartwood of yew is on the inside of the bow while the sapwood is on the outside. This takes advantage of the natural properties of yew wood since the heartwood resists compression while the sapwood resists stretching. This increased the strength and efficiency of the bow. Much yew is knotty and twisted, so unsuitable for bowmaking; most trunks do not give good staves and even in a good trunk much wood has to be discarded.

The trade of yew wood to England for longbows was such that it depleted the stocks of good-quality, mature yew over a vast area. The first documented import of yew bowstaves to England was in 1294. In 1350 there was a serious shortage, and Henry IV of England ordered his royal bowyer to enter private land and cut yew and other woods. In 1470 compulsory archery practice was renewed, and hazel, ash, and laburnum were specifically allowed for practice bows. Supplies still proved insufficient, until by the Statute of Westminster in 1472, every ship coming to an English port had to bring four bowstaves for every tun. Richard III of England increased this to ten for every tun. This stimulated a vast network of extraction and supply, which formed part of royal monopolies in southern Germany and Austria. In 1483, the price of bowstaves rose from two to eight pounds per hundred, and in 1510 the Venetians would only sell a hundred for sixteen pounds. In 1507 the Holy Roman Emperor asked the Duke of Bavaria to stop cutting yew, but the trade was profitable, and in 1532 the royal monopoly was granted for the usual quantity "if there are that many." In 1562, the Bavarian government sent a long plea to the Holy Roman Emperor asking him to stop the cutting of yew, and outlining the damage done to the forests by its selective extraction, which broke the canopy and allowed wind to destroy neighbouring trees. In 1568, despite a request from Saxony, no royal monopoly was granted because there was no yew to cut, and the next year Bavaria and Austria similarly failed to produce enough yew to justify a royal monopoly. Forestry records in this area in the 17th century do not mention yew, and it seems that no mature trees were to be had. The English tried to obtain supplies from the Baltic, but at this period bows were being replaced by guns in any case.

 

Sorce: wikipedia.org

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