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The majority of commissions are from private
individuals, however previous customers include:
ENGLISH HERITAGE
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Tree species suitable for
tree-ring dating
| We are specialists in dating oak from
the regions of England and NW France, although oak from other regions may
also be dated. In England, Oak (Quercus. spp) has the
greatest potential for dating although other tree species: Ash (Faxinus
excelsior), Beech (Fagus sylvatica), Elm (Ulmus. spp),
Pine (Pinus. spp), and Yew (Taxus baccata) may to a lesser
extent be dated through tree-ring analysis.
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Identification of Wood Species
| As previously stated, oak has the
greatest potential for dating in England, which fortunately coincides with
the fact that in the past it was the most commonly used wood. Identifying
the different tree species is more difficult than when they are not living
trees. Oak is also relatively easy wood to identify, but difficulties with
other species may occur. |
| Colour alone is a poor guide to
identifying a wood species as staining has long been used to make one type
of wood look like another. Surfaces coated with either varnish or wax can
often fill the pores as well as change the colour of the wood and make
identification difficult.
A simple reference guide for the identification of
tree species from the wood alone follows. The guide is purely intended to
help you identify the various species of wood which commonly are found in
domestic and architectural use in Britain. Please note that you do not
have to identify any wood to a species before you can send it for dating,
the identification process will be completed by Tree-Ring Services.
Growth rings in softwoods are often clearly visible
because each one is composed of both less dense (usually lighter coloured)
earlywood formed in spring/early summer; and denser (darker), latewood
formed in late-summer/autumn. Sapwood contains the tubes that carry water
up through the tree. On an end-grain or cross-section these tubes appear
as holes which are referred to as pores. In softwoods (conifers) pores are
very small and hard to see, whereas in hardwoods (i.e. broad leaved trees)
they are usually readily visible.
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The 6 main species for dating and their
identifying characteristics
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Oak: Large pores,
easily seen at normal reading distance, are noticeably concentrated in
the earlywood. Large prominent rays (some finer between). Many pores
between large rays and finer rays between pores. Smaller pores of late
wood may form a radial "flames" pattern. |
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Elm: Large pores
with an abrupt change between earlywood and latewood, and wavy parallel
lines of medium pores in the latewood. Fine and medium rays, (just visible
to the naked eye when the wood is wet). One or two pores between rays.
Wood dull yellow, brown or pink, and coarse grained. |
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Ash: Large to
medium pores, oval in shape. Earlywood gradually merges to latewood. Pores
occur singularly or in radial chains especially in latewood (2-5 in a
chain). Fine rays with one or two pores between rays. |
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Beech: Pores are
small to medium and may not be visible to the naked eye. Pores gradually
decrease in size and number outward within each ring. Mixture of fine
(hard to see) and large rays with more than six pores between large rays.
Wood white or pale yellow with distinctive red-brown flecks on the
longitudinal face (i.e., not on the end-grain). |
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Pine: Pores
normally visible with a hand-lens. Rings distinct with an abrupt
transition between the dark latewood and pale earlywood. Soft wood, does
not resist fingernail pressure. Colour:- White, yellow or
red-brown. |
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Yew: Pores not
visible. Prominent rings defined by dark latewood. Hard wood, resists
fingernail pressure. Colour:- red/brown (often yellow near
bark). |
| The illustrations show the microscopic
structure of the woods. Rays radiate out from the centre of the tree and
these
may be narrow or wide depending of the tree species. The number of pores
sandwiched between the rays, (counting the number of pores encountered
along any line at right-angles to the rays), varies between tree species.
Pores may also be singular (discrete from each other) as seen in oak or
joined into short radial chains (where a number of pores are closely
pressed together in a line approximately parallel to the rays) as can be
seen in ash.
If difficulties occur in species identification there
are usually books available in your local Library which can help in the
identification of wood through various features. Please note that even in
a single species such as oak, the pores in the earlywood can vary
considerably in general number, size and distribution, as can the average
ring-widths. Pine and spruce may be confused, though spruce shows a
gradual transition between latewood and earlywood, also pine may have a
resinous smell that spruce does not.
Commercial timbers (Richter and Dallwitz 2000) provide an on-line
database for wood anatomy and wood identification containing descriptions.
They also make available an interactive identification system for hardwood
taxa common in the international trade that occur in all major forest
regions of the world.
Updated:
28/12/2006
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FREE example reports on
Live trees or
Historic Buildings, in PDF format.
New Items:
Churchyard yew
tree reports
Surrey Dendro Project.
Over 100 buildings dated as part of this Heritage Lottery supported project.
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