Pollen and plant macrofossil analyses of lake sediments from Anthony Island in the southern Queen Charlotte Islands (Haida Gwaii), British Columbia, reveal 1800 yr of relatively stable temperate rainforest vegetation. Cupressaceae (cedar) pollen percentages and accumulation rates decline about 1000 cal yr BP, coincident with occupation of the island by Haida peoples, who use Thuja plicata (western red cedar) almost exclusively for house construction, dugout canoes, monumental poles, and many other items. Anthropogenic disturbance offers the most likely explanation for the decline of T. plicata.