Ruth,

High heat does a whole bunch of stuff to stone or mortar. Magma is stone
in high heat.
Depends on the materials and depends on the amount of heat.
As to controlled burns in Indiana cemeteries I would suspect that the
gravestones are more than likely being damaged.
Though to prove this out may be difficult as micro-damage is not always
easily recognized as promoting an incremental increase in long-term and
radical decay of stone.
Scientific investigation would be for a study to be made by a materials
conservator of the effect of the controlled burns on the masonry in the
specific cemeteries.
Possibly comparing of weathering effects on stones in non-burn
cemeteries of comparative age & climate etc.
Such a study would require sufficient interest for there to be funding.
Speculation as to the effect would not be very scientific.
In the mean time controlled burns would likely continue.

][<en


Ruth Barton wrote:

>This is a question asked on another list I'm on.  I don't know the answer
>and since controlled burn would be a convenient way to clear brush I'm
>curious to know the answer.  Anybody?  Thanks,  Ruth
>
>
>
>
>Controlled burns are used in Dept of Natural Resource properties in about 5
>DNR controlled cemeteries in Indiana....the real question has NEVER been
>answered by DNR or scientific research....and that is what does high heat
>and burning do to the stone and mortars?
>--
>Ruth Barton
>[log in to unmask]
>Dummerston, VT
>
>--
>To terminate puerile preservation prattling among pals and the
>uncoffee-ed, or to change your settings, go to:
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>
>
>
>

--
To terminate puerile preservation prattling among pals and the
uncoffee-ed, or to change your settings, go to:
<http://maelstrom.stjohns.edu/archives/bullamanka-pinheads.html>