Rough-hewn logs

Carolyn W. Koenig inquired about the treatments necessary to bring
real trees and logs into a museum for long-term exhibition.

We have been doing this for several years both at the Minnesota
History Center and at one of our historic site museums, the Mille
Lacs Indian Museum.  We have not had any problems with insect
infestation by following this protocol:

    1.  Choose healthy, non-diseased trees.  Don't collect logs that
        have already been on the damp ground for some time.

    2.  Have a conservator, or someone who is experienced with
        examining objects for a wide range of pest infestations,
        look at the trees in the field, if possible, or at least
        before they are brought into the institution. This step is
        critical!

    3.  Once the trees/logs are cleared for use, have them cleaned
        of debris and extraneous dirt, etc. outside the building.
        Have them kiln-dried for as long as it takes to thoroughly
        dry them based on their size and weight.  This can usually
        be done by a local lumber yard.  This is a precaution that
        will both dry excess moisture and kill all stages of boring
        insects that might not have been detected.  The larval
        stages of wood boring insects need a high EMC in the wood to
        grow, so keeping it low is a good preventative measure. Slow
        kiln drying done properly should not cause warpage or
        destroy the "natural" look of the trees/logs.

    4.  Continual monitoring of the 'useable objects' as part of
        your institutional Integrated Pest Management Program (IPM).
        Inspect the trees/logs periodically for signs of active
        infestation, and if it is occurring, determine whether the
        trees/log are the source or whether it was introduced from
        elsewhere.

As far as a source for fake trees goes, you can check with local
theatrical prop fabrication companies.  You might also want to
contact the exhibits dept. at the South Carolina State Museum in
Columbia, SC. They were very adept at making fiberglass replicas of
trees and making leaves through a plastic casting technique.

Paul S. Storch
Objects Conservator
John and Martha Daniels Objects Conservation Laboratory (JMD-OCL)
B-109.1, Minnesota History Center
345 Kellogg Blvd West
St. Paul, MN  55102-1906
612-297-5774
Fax: 612-297-2967

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                  Conservation DistList Instance 11:29
               Distributed: Thursday, September 25, 1997
                       Message Id: cdl-11-29-006
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