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Yew tree age estimates
Small stands of yew and many of the largest trees may
be found in the churchyards and cemeteries of England and Wales, and the
parish churches of Britain provide a unique assemblage of the largest yews
known in Europe.
English
yew (Taxus baccata L.) is generally acknowledged as the British
tree capable of longest life, Bevan-Jones
reviews
the evidence concluding: "evidence from many quarters emphasises the
reality that these trees frequently exceed a thousand years growth".
Distribution and girth of some yew trees in the south of the U.K.
(click map to enlarge)

The
estimation of the age of yews has been a contentious subject for
centuries, not least because those specimens over 4.57m girth are normally
hollow. Tree age estimation in the U.K. has remained largely based on
girth measurement comparisons, but exceptionally large trees have
been aged by different methods and estimates can widely vary accordingly.
An
estimate of the age of churchyard yew trees from girth

* Age Estimate = based on formula published by
Tabbush & White (1996) and is based on research on churchyard yews
The
only precise way to determine the age of a living tree is to measure
tree rings usually in a section or increment core that intersect the pith of the tree. The use
of a narrow (5.14mm) diameter increment corer to sample a live tree offers
the same astonishing impact of absolute tree-ring dates as has been
achieved with the dating of historic timber-framed buildings in this
country. While the girth of our very largest trees (and hence the trees of
greatest interest) may make it impossible to reach their piths with
increment borer, increment sampling still offers the most
accurate empiric refinement to the estimation of a tree's age.
In some instances we can also use a technique which combines the mean
growth rate information from a site to further refine the age estimation
of trees sampled.
Taking a small
(5.14mm) core from a yew tree

Yew has
been show to have considerable dendrochronological potential, however
tree-ring analysis has yet to be applied to a tree over 5.20m in girth. There are a number of particular problems in the
dendrochronological study of yew, for example, slow growth in this species
may lead to extremely narrow rings, and in some cases, locally absent or
"missing" rings which can cause potential ring counting errors during
measurement. Another problem is the common irregular and lobate growth
pattern of the trunk and the consequent risk of missing rings from core
samples.
However, recent research has demonstrated that yew may be successfully
core sampled from lobe sections of growth and dendrochronologically
analysed.
For the cost of dating a Churchyard yew tree by tree-ring analysis click: costs.
A yew tree approximately 3 meters in girth and so
estimated to be 300 years old was recently in danger of being fell, at Hunton
Bridge, Herts. Advice from the Ancient Tree Forum lead to the contact of
the District Council’s Tree Officer, who arrived within the hour to apply
an emergency Tree Preservation Order. It was later discovered that the
tree was also an important roost site for bats. All bats are specially
protected species. For this and other recent news articles on trees see
the Ancient Tree Forum's
Latest ATF news.
Further reading
Moir, A K
2004
Dendrochronological analysis of a Churchyard yew tree from West Horsley, Surrey, England, Tree-Ring
Services, Dendrochronological Report, WHCX/xx/04 (Out Soon)
Moir, A K
2003
Dendrochronological analysis of two yew trees and one oak tree from St.
John the Baptist Churchyard, Capel, Surrey, England, Tree-Ring
Services, Dendrochronological Report, CACY/27/03.
Moir, A K
2003
Dendrochronological analysis of trees from St. James the Great Church,
Thorley, Bishop's Stortford, Hertfordshire, England, Tree-Ring
Services, Dendrochronological Report,
THCY/04/03.
Moir, A K,
1999 The dendrochronological potential of modern yew (Taxus
baccata) with special reference to yew from Hampton Court Palace, UK,
New Phytologist 144, 479-488.
Tabbush,
P, White, J E J
,
1996 Estimation of tree age in ancient yew woodland at Kingley
Vale. Quaterly Journal of Forestry 90: 197-206.
Updated:
28/12/2006
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