Dear Hans
At 05:25 PM 5/11/99 +0200, you wrote:
>Henry CLEERE wrote:
>>
>> The charcoal from the 2nd century AD Roman (military?) ironmaking site of
>> Bardown, East Sussex, proved to come from a large number of different tree
>> species - even including elder/sambucus. This was interpreted as meaning
>> that the ironmakers used any trees in the area.
>
>As an archaeologist, some years ago I worked on the
>Early Medieval (c. 7-9.century AD) settlement of
>Kelheim, Lower Bavaria, Germany. The economic focus
>in this site was on smelting iron ore and refining
>the raw iron. We analysed a large amount of
>charcoal, and found that oak (quercus) was by far
>the predominant species, followed by pine (pinus),
>while all other species only turned up occasionally.
>
>In the use of wood for charcoal there is obviously
>no relation to the natural occurence of trees in the
>surrounding forests. It seems that here charcoal was
>custom made to suit the demands of the iron
>producers. In consequence it may be assumed that
>some sort of sustainable forestry should also have
>been adopted.
Yes, I agree that early ironmakers practised forestry management - we have
evidence of coppicing at Bardown. Oak certainly predominated in our
charcoals from there, but one would expect it to, since that is the climax
woodland species on the heavy clays in the Weald. My point is that the early
ironmakers used virtually anything that came to hand: there was not the
careful selection that one finds in the early modern period, when furnace
dimensions were much larger and it was necessary to have a strong charcoal.
In the same area hornbeam was deliberately planted in the 17th century
because it is a fast-growing hardwood that produces strong charcoal capable
of withstanding the internal pressures from the heavy burdens of large furnaces.
When I did my smelting experiments in a reconstructed 2nd century AD furnace
some thirty years ago we made quite a lot of our own charcoal, using oak and
hornbeam. However, I needed more, and so I bought it from a nearby supplier
of charcoal for barbecues. We analysed it and found an equally wide range of
wood used - including one piece from a plywood jigsaw puzzle! It was
certainly less strong than what we had made ourselves, but with a shaft 30cm
in diameter by less than 1m high it worked just as well.
Henry Cleere
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