Examining past treatments of cedar and spruce waterlogged basketry from the Northwest Coast

Dana K. Senge and Ellen Carrlee

Abstract

Basketry artifacts fabricated from limb wood, spruce and cedar root, and the inner bark of yellow and western red cedar have been found in water-saturated archaeological sites in the Pacific Northwest since the mid-20th century. These artifacts range in age from a few centuries to more than five thousand years old. While these materials retain their overall physical structure due to burial in an anoxic environment they are degraded on the cellular level. Experiments and treatments performed by archaeologists and conservators over the past 40 years have attempted to stabilize these degraded structures to minimize splitting, crumbing, and distortion of the woven structures as they dried. Early treatments were guided by research done for preserving waterlogged ship timbers from the Vasa warship in Sweden and boats from Lake George, New York. Recent research has shown that the size of typical basketry elements limits the use of the PEGcon computer program developed at the Canadian Conservation Institute to determine the level of cellular degradation and that the cellular structure of some basketry material, such as inner bark, differs enough from trunk wood to require a variation in treatment. Recommendations for the best conservation methods for these materials is still under examination as conservators in Alaska, British Columbia, the Pacific Northwest, and scientists at the Canadian Conservation Institute continue to study the woody elements of these artifacts and the effects of treatment products. This paper summarizes and compares past treatments and the current condition of basketry from multiple wet sites on the Northwest Coast and discusses some of the current avenues under research.

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