Prehistoric human influence on the abundance and distribution of deadwood in alpine landscapes

Scientists have long inferred the locations of past treelines from the distribution of deadwood above modern tree boundaries. Although it is recognized that deadwood above treeline may have decayed, the absence of such wood is routinely taken to imply the absence of trees for periods ranging from the past few millennia to the entire Holocene. Reconstructed treeline histories are then explained in terms of such variables as slope, drainage, temperature, solar insolation, and precipitation. While these variables certainly help determine where deadwood is to be found above treeline today, we suggest that they cannot always explain where it is not to be found. In the alpine environments of the western United States, archeological work has established a human presence during nearly the entire Holocene in portions of the Rocky Mountains and for over 5000 radiocarbon years in the Great Basin and Sierra Nevada. We suggest that prehistoric occupations may have stripped deadwood from the landscape in all of these areas. To the extent that this is true, reconstructions of past treelines from deadwood may reflect the human prehistory of an area as much as it reflects treeline history itself. We encourage evaluation of this hypothesis in areas of active dendrochronological and archeological research.