Evaluation To Date

   Research has indicated that borate preservatives can be effective in controlling most fungal decay and insect damage to above-ground wood. The type of wood involved, depth of penetration of the preservative, and site conditions may influence its effectiveness. It can be applied to seasoned unpainted wood in the field or under shop conditions using brushes, garden sprayers, or a dip trough.

Application of a water repellent to the totems will probably be needed approximately every 3 years. This can easily be done in place. The support post's "bandage" wrap located just below grade, will need to be inspected in about 10 years.

   Selected for use in various totem poles at Sitka because of its purported effectiveness and relative safety, borate treatment has potentially broad applications to wooden structures and outdoor artifacts. Log buildings, window sills, and above-ground outdoor wooden objects subject to decay or insect damage are just some of the potential applications. There are commercially available borate preservatives designed for topical applications to seasoned or partially seasoned wood such as that which was applied to the poles at Sitka. Careful monitoring of the carvings on the poles along with the test log will help document the long-term value of borate preservatives when applied to unpainted wood in this moist environment. Successful results will depend in part on regular maintenance of the poles, particularly in removing collected organic debris and in periodically re-applying a water repellent coating.

For Future Reading

    For an extensive technical and historical review of borates for wood protection, consult the proceedings of the First International Conference on Wood Protection with Diffusible Preservatives. (Available from the Forest Products Society (Telephone 608-231-1361).

   Barnes, H.M.; Amburgey, T.L.; Williams, L. H.; Morrell, J.J. 1989. "Borates as Wood Preserving Compounds: The Status of Research in the United States." In: Proceedings of the International Research Group on Wood Preservation-Working Group III: Preservatives and Methods of Treatment; 1989 March 31; Stockholm, Sweden: IRG Secretariat; Document No: IRG/WP/3542.

   Curtis, A. B., Jr.; Williams, Lonnie H. 1990. "Borates Offer Effective Protection with Less Hazard to the Environment." Technology Update, Southern Region, U.S. Department of Agriculture, Forest Service. Utilization Report R8-UR 6.

   Quarles, William, "Borates Provide Least Toxic Wood Protection," The IPM Practitioner.

   Williams, Lonnie H. 1990. "Diffusion Treatment of Domestic and Tropical Hardwood Lumber for Long-term Protection from Decay Fungi and Insects." In: Proceedings 47355. First International Conference on Wood Protection with Diffusible Preservatives. 1990 November 27-30; Nashville, TN.

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