Is Yew wood NOT poisonous when dry?
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It appears that drying has no effect on the poison. In other words it is just as poison when dry.
The Yew as a poisonous plant
The red fleshy part of the fruit is quite edible and are eagerly eaten by many birds, such as fieldfares, thrushes, blackbirds and redwings. The hard seeds pass through them without harm and are distributed in their droppings. Country children have often not been able to resist the temptation to eat the sweet attractive looking flesh, but such familiarity with the tree may have its real dangers, as they might chew the seeds in the arils, or even be tempted to chew the green shoots.
All parts of the tree, except for the flesh of the arils are very poisonous.
"They contain the highly poisonous alkaloid taxin, a small amount of auxiliary alkaloids and the glycoside taxicatin. The needles contain the greatest concentration of taxin in the winter (2 percent) and the least concentration in the summer (0.5 percent). The seeds contain approximately 1 percent. The decoction from just 50 - 100 gm of needles or a mere 30 'berries' is fatal for an adult."
"The action of the poison is extremely rapid because taxin is quickly absorbed in the digestive system. It is a very poisonous cardiovascular toxic substance and causes vomiting and abdominal pains, painful diarrhoea, dilated pupils, pallor, collapse, cramps, unconsciousness, and death due to cardiac arrest and respiratory failure often within an hour following ingestion. Horses are the most susceptible of all animals and may die within several minutes of feeding on the young shoots. The literature states that 100 - 200 gm of the needles is a fatal dose for a horse. Pigs are also susceptible, but a five-fold amount is required to poison cattle." (from F. Starý "Poisonous Plants" Magna Books, 1990).
The above quotation explains what has often been a mystery to many country people: how can cows browse on the tree and walk away unharmed on some occasions and yet be poisoned after a short nibble at other times. It seems to me that the tree is purposefully trying to protect itself by increasing the amount of toxins in the winter, when it may be the only bit of greenery around. A similar phenomena occurs, as we noted above,when talking about collecting Trimmings from a Yew hedges and topiary trees for medicinal purposes: They have to be from trees, which are trimmed every year, because the Taxol (also a potentially toxic alkaloid) is produced in much greater quantities in new growth! It is also interesting to note that clipped and half-withered yew branches are said to be especially poisonous to cattle.
Hageneder reports that 0.2-03 gr of yew leaves per kilogram of body weight is regarded as a fatal dose for a horse. About 1 gram of leaves, or 3-5 seeds, per kilogram of bodyweight is fatal to human being. Small children are more sensitive to the toxin, as they are to all medicine. He also says that "Some wild animals feed on Yew, particularly deer who receive some kind of 'kick' from the yew's alkaloids (nitrogen compounds)."(Hageneder "Spirit of Trees, science, symbiosis and inspiration", Floris Books, 2000)
Finally one more contribution on the subject seems justified in view of its potential importance. The following quotes are from "A guide to wild plants, the edible and poisonous species of the Northern Hemisphere" by M. Jordan, B Sc., M.Inst.Biol., Millington 1976:
"Initial symptoms are nausea and vomiting, accompanied by severe abdominal pain and diarrhoea. There is a rapid weakening of the muscles, and the skin becomes cold and clammy, with a pallid appearance caused by peripheral circulatory failure. The toxin acts as a cardiac depressant, and the heartbeat becomes drastically slowed.
The terminal phase is normally rapid and may involve delirium and convulsions prior to coma. Death is from heart failure or, less frequently, asphyxia. The lethal dose for an adult is estimated to be not less than 50 gm. of the leaves, but as few as 4 or 5 of the seeds may prove fatal for a child."
"In cattle, which browse on yew, death can be sudden and often without any prior symptoms, and the virulence of the toxin is in no way diminished by drying in fodder. It is interesting to note that British law recognises the careless disposal of yew clippings as a basis for award of damages when stock has been lost through taxine poisoning."
"Treatment: no specific antidote is recognised for taxine poisoning, and therefore normal first aid must be very prompt. Stomach washing by qualified medical personal with weak tannic acid solution followed by treatment with activated charcoal suspension must follow rapidly, and where indicated appropriate drug therapy to stimulate the heart."
The Yew as a poisonous plant
The red fleshy part of the fruit is quite edible and are eagerly eaten by many birds, such as fieldfares, thrushes, blackbirds and redwings. The hard seeds pass through them without harm and are distributed in their droppings. Country children have often not been able to resist the temptation to eat the sweet attractive looking flesh, but such familiarity with the tree may have its real dangers, as they might chew the seeds in the arils, or even be tempted to chew the green shoots.
All parts of the tree, except for the flesh of the arils are very poisonous.
"They contain the highly poisonous alkaloid taxin, a small amount of auxiliary alkaloids and the glycoside taxicatin. The needles contain the greatest concentration of taxin in the winter (2 percent) and the least concentration in the summer (0.5 percent). The seeds contain approximately 1 percent. The decoction from just 50 - 100 gm of needles or a mere 30 'berries' is fatal for an adult."
"The action of the poison is extremely rapid because taxin is quickly absorbed in the digestive system. It is a very poisonous cardiovascular toxic substance and causes vomiting and abdominal pains, painful diarrhoea, dilated pupils, pallor, collapse, cramps, unconsciousness, and death due to cardiac arrest and respiratory failure often within an hour following ingestion. Horses are the most susceptible of all animals and may die within several minutes of feeding on the young shoots. The literature states that 100 - 200 gm of the needles is a fatal dose for a horse. Pigs are also susceptible, but a five-fold amount is required to poison cattle." (from F. Starý "Poisonous Plants" Magna Books, 1990).
The above quotation explains what has often been a mystery to many country people: how can cows browse on the tree and walk away unharmed on some occasions and yet be poisoned after a short nibble at other times. It seems to me that the tree is purposefully trying to protect itself by increasing the amount of toxins in the winter, when it may be the only bit of greenery around. A similar phenomena occurs, as we noted above,when talking about collecting Trimmings from a Yew hedges and topiary trees for medicinal purposes: They have to be from trees, which are trimmed every year, because the Taxol (also a potentially toxic alkaloid) is produced in much greater quantities in new growth! It is also interesting to note that clipped and half-withered yew branches are said to be especially poisonous to cattle.
Hageneder reports that 0.2-03 gr of yew leaves per kilogram of body weight is regarded as a fatal dose for a horse. About 1 gram of leaves, or 3-5 seeds, per kilogram of bodyweight is fatal to human being. Small children are more sensitive to the toxin, as they are to all medicine. He also says that "Some wild animals feed on Yew, particularly deer who receive some kind of 'kick' from the yew's alkaloids (nitrogen compounds)."(Hageneder "Spirit of Trees, science, symbiosis and inspiration", Floris Books, 2000)
Finally one more contribution on the subject seems justified in view of its potential importance. The following quotes are from "A guide to wild plants, the edible and poisonous species of the Northern Hemisphere" by M. Jordan, B Sc., M.Inst.Biol., Millington 1976:
"Initial symptoms are nausea and vomiting, accompanied by severe abdominal pain and diarrhoea. There is a rapid weakening of the muscles, and the skin becomes cold and clammy, with a pallid appearance caused by peripheral circulatory failure. The toxin acts as a cardiac depressant, and the heartbeat becomes drastically slowed.
The terminal phase is normally rapid and may involve delirium and convulsions prior to coma. Death is from heart failure or, less frequently, asphyxia. The lethal dose for an adult is estimated to be not less than 50 gm. of the leaves, but as few as 4 or 5 of the seeds may prove fatal for a child."
"In cattle, which browse on yew, death can be sudden and often without any prior symptoms, and the virulence of the toxin is in no way diminished by drying in fodder. It is interesting to note that British law recognises the careless disposal of yew clippings as a basis for award of damages when stock has been lost through taxine poisoning."
"Treatment: no specific antidote is recognised for taxine poisoning, and therefore normal first aid must be very prompt. Stomach washing by qualified medical personal with weak tannic acid solution followed by treatment with activated charcoal suspension must follow rapidly, and where indicated appropriate drug therapy to stimulate the heart."
