Author: Jeffrey Nathan Crawford

Publisher:

Published: 2012

Total Pages: 306

ISBN-13:

Observers of human/landscape interactions generally agree that Native Americans influenced the landscape, but disagreement exists regarding the scale and degree of this disturbance. The differentiation of anthropogenic from climatic impacts on forest structure and composition is difficult using traditional paleoecological methodologies. The goal of this dissertation is to examine potential human impacts in the paleoecological record using an alternative methodology that incorporates elements of paleoecology, ethnographies, and regional archeology. This will provide a better understanding of how to identify potential anthropogenic signals in the late Holocene and improve upon existing paleoecological methodologies by allowing a more complete analysis of how human culture has impacted physical landscapes. Two lake basins in the Klamath Mountains of northwestern California provided study sites to use a cross-disciplinary methodology. There are three significant facets to this research. The first is a comparison of cross-dated fire scars to the sedimentary charcoal record of fire events. This was used to establish whether the fires detected in the paleoecological (charcoal) record represented local fire events that occurred within or near the lake basins. The results suggest that, while not a perfect match, fire events observed in the sedimentary charcoal record (as charcoal peaks) corresponded with between 50.0% (at Fish Lake) and 87.5% (at Lake Ogaromtoc) of known and inferred fire events detected as fire-scarred trees in the study basins. The second step in detecting anthropogenic landscape impacts in the paleoecological record was to identify anomalous periods of fire and vegetation dynamics not well explained by climate. Vegetation was reconstructed through the analysis of pollen. Paleofire dynamics were reconstructed through the analysis of sedimentary charcoal. Three anomalous periods were identified for further evaluation. In the final step of this research, these three anomalous periods were examined to see if cultural land-use patterns drawn from the regional archeological and anthropological record could better explain the observed dynamics. In all three instances, cultural changes in population or land use patterns better explained the observed dynamics than climatic interpretations, providing evidence of Native American impacts on the fire and vegetation dynamics of the two study sites in the late Holocene. This research provides subtle but clear evidence that human impacts are present at both study sites in modern and pre-historic times. Native American burning practices that have been banned since European settlement strongly influenced the forest structure and fire regimes of the Klamath Mountains. The cessation of Native American burning and modern fire suppression has led to a forest assemblage at each site that is unique in the late Holocene record. This research increases our understanding of how past forests in the Klamath Mountains responded to anthropogenic and climatic forces and encourages modern forest management practices to tailor restoration prescriptions to meet multiple human and ecosystem needs. This research also has broader implications for paleoecological methodologies. A single study cannot resolve the debate over the scale of Native American influences, but further replication of this cross-disciplinary methodology is encouraged at other sites throughout California. Further replication will build a broader dataset of sites, help to determine the scale of Native American impacts, and foster a greater understanding of the connections between the cultural and physical aspects of landscapes in the Klamath Mountains and beyond.