The two Bronze age timber circles at NWT Holme Dunes are revealed to have been felled at exactly the same time, thanks to precise tree ring dating.
In the late 1990s two remarkable and well-preserved Bronze Age timber circles were discovered on Holme Beach. One of these – Seahenge – was excavated in 1999. Since the excavations the second circle has been monitored and evidence of damage by coastal processes has been recorded. Tree ring dating (dendrochronology) undertaken in the last year has shown the timbers used to build the second circle were felled in the spring or summer of 2049 BC. This means that the timbers were felled at exactly the same time as those used to build Seahenge. The felling date places the construction of both circles early in the Bronze Age.
Prehistoric timbers rarely survive and have been found at only two of the United Kingdom’s timber circles, both of which were on Holme Beach. The presence of timbers within circles is normally suggested by soil-filled holes that would once have supported posts.
The exceptional survival of the timber circles at Holme Beach means they are the only ones to have been dated precisely by tree ring dating. Most timber circles are dated to within a number of centuries, based on pottery types or radiocarbon dating of organic material (such as charcoal or bone).
Between 2004 and 2013 archaeologists working for Norfolk County Council’s Historic Environment Service recovered sections of seven timbers from the second circle. The tree rings visible in these timbers were measured and compared to tree ring sequences from Great Britain and northern Europe. The measurements of the circle’s tree rings were very similar those from other Bronze Age timbers and were directly comparable to those from Seahenge.
When first fully revealed by the sea the second circle was made up of four elements. At its centre were two oak logs laid flat. These were surrounded by an oval of oak posts with oak branches woven between them. On the eastern side of the monument there was an arc of split oak timbers. Surrounding all the other elements was an outer palisade of split oak timbers, with the timbers set side-by-side.
The reasons why the second circle was built are not clear, but it may have formed part of a burial mound. The two central logs may originally have supported a coffin. The oval of posts and woven branches could have hidden the coffin from view before a mound was added, with the outer palisade acting as a revetment for the base of the mound.
As the timbers used in both timber circles were felled at the same time, the construction of the two monuments must have been directly linked. Seahenge is thought to have been a free standing timber circle, possibly to mark the death of an individual, acting as a cenotaph, symbolising death rather than a location for burial. If part of a burial mound, the second circle would have been the actual burial place.
Since 1999 coastal processes have damaged the second circle. By 2003 all the woven oak branches had been lost and in October 2003 one of the central logs was washed away. The second central log was dislodged by the sea in March 2004. From 1999 to May 2005 and between December 2010 and December 2013 the sediments around the palisade timbers were gradually eroded, leading to the exposure of more of the circle’s timbers. This erosion and the loss of timbers prompted the dating project to collect important information before it was lost forever.
As the second timber circle is currently covered by sand, it is entirely hidden from view. Holme Beach is an internationally important wildlife habitat protected by United Kingdom and European legislation, as are many of the species that use it. As both the habitat and its species are vulnerable to disturbance, all visits should be undertaken with great care.
NWT Holme Dune National Nature Reserve is part of the North Norfolk Coast SSSI (Site of Special Scientific Interest) and is internationally important for wildlife, especially birds. The peat beds - the location of the two timber circles - are an integral part of the nature reserve. In particular the peat substrate provides important habitat for large numbers of marine invertebrates that, on exposure at low tide, are a rich source of feeding for a large number of wading birds; arguably the roosts are the single most important feature on the whole North Norfolk Coast and are vulnerable to disturbance.
Kevin Hart, Head of Nature Reserves said: “The quality of the wildlife habitat at NWT Holme Dunes is reflected in the fact that it holds nearly every national and international statutory protection available. Norfolk Wildlife Trust requests that visitors respect this special reserve because of the many bird species using the beach at this time of year. This second wooden circle is below the high water mark and is currently buried sand and is not visible.”
The scientific research project was funded by English Heritage. It was undertaken with the agreement of Norfolk Wildlife Trust. It is hoped the project’s results will be published in full in the near future.