Fog represents a significant water resource for redwood (Sequoia sempervirens) forests. The availability of fog for plants may depend on a number of climatic factors, such as sea surface temperatures (El Nino events) and drought. The objective of this study is to quantify historic fog utilization patterns by redwood trees using stable isotope analysis of water sources and tree-ring cellulose. This is an interdisciplinary project that links diverse fields of study such as biology, biogeochemistry, paleoclimatology, ecosystem hydrology, oceanography and meteorology. This study will lay the foundation for understanding how the climatic signals associated with fog water utilization are recorded in tree-rings. Slabs of already harvested ancient Redwood trees could provide 1000+ year reconstructions of the periodicity and strength of important climatic cycles. A historic record of hydrologic inputs for these trees is critical for understanding how climatic change, climatic variation as well as forest management practices influence the vigor of this endangered ecosystem. The proposed research will primarily use stable isotope analysis of water sources and tree-ring cellulose to determine current and past fog water utilization by Redwood trees. Isotopes are passive tracers of transformations within organisms and the biosphere. Weather records from nearby stations will be used to calibrate recent tree ring signals with recent climatic events. Current environmental conditions and water sources will also be quantified to enhance modeling efforts to link cellulose isotopic composition and climate.
