At some point if a building project or equivalent is anticipated then it will prove necessary to undertake various forms of survey to determine what if anything might be disturbed or damaged. The most common form of survey is to employ the use of a metal detector to establish what is present in the leaf letter, forest duff below and the underlying mineral soil.
When preparing a large area for a building project it is worth raking away the leaf litter, twigs and fallen branches and then the forest duff to get down to the mineral soil and piling the removed material is discrete areas rather than mixing this with the mineral soil that might need to be excavated and dumped.
The metal detecting survey can be undertaken covering the whole site in strips as the layers are peeled away.
To obtain meaningfull results its probably necessary to spend in the region of £250 - £300 in buying a good detector. The XP detector employed has two modes of detecting - the 'all metal' which does what it says and finds everything metallic and the other is 'discriminate' which takes out small ferrous signals leaving everything else including base and precious metals.
In addition to the metal detector wand it is adviseable to purchase a small directional detector which can be used to more accurately detect the location of metal items that the wand had detected.
As items are recovered it is worth recording this on a site sketch or by labelling the ground and photographically recording same.
The most common items that might be recovered from a woodland site will likely be bits of barbed wire and associated staples (1850 onwards), plough shares, bits of old bicycles (1900 onwards), household wares such as enamelled metal buckets, bottle tops (1900 onward), drinks cans (1950 onward), etc.
In the woodland site shown above a number of lead muskett balls were found both at and below mineral soil level and so it might be resonable to deduce that at some time this area of woodland had been ploughed causing items deposited at surface level to mix into the subsoil. This kind of discovery can provide input into helping to interpret the history of the site so for example the above site is probably not an ancient woodland site (i.e. under continuous tree cover since 1600) since the musket balls are most likely to be from the English Civil war period when Reading and the Chiltern Hills were held by parliamentary forces with Royalist forces based in Oxford to the north. Further aerial photographic archive research (Britain from above) has confirmed that this site was a ploughed arable field in 1950.
Having completed the archaeological survey the barn site was then free to be excavated to create a level area upon which the framing (or lofting) floor could be laid out and fixed in position ready to accept the timber-frames.
Regards
Ken Hume
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Author
Metal Detectoring