HR: 0800h
AN: B31A-0976    [Abstracts]
TI: Fog Inputs and Edge Effects From Canopy to Soil in a California Redwood Forest
AU: * Ewing, H A
EM: hewing@bates.edu
AF: Bates College Environmental Studies Program, 111 Bardwell St., Lewiston, ME 04240 United States
AU: Weathers, K C
EM: weathersk@ecostudies.org
AF: Institute of Ecosystem Studies, Box AB, Millbrook, NY 12545 United States
AU: Elliott, A
EM: elliotta@ecostudies.org
AF: Institute of Ecosystem Studies, Box AB, Millbrook, NY 12545 United States
AB: As a horizontally-driven vector, fog interacts with the structure of the landscape to create spatial patterns of deposition not seen in the more even distribution of vertically-delivered rainwater inputs. In coastal CA, fog arrives during the summer growing season when trees are most physiologically active and rainfall is negligible, thus it may be an ecologically significant source of water and nutrients. We are examining the interaction of horizontal and vertical inputs with forest structure, and the influence of these inputs on plant physiology, ecosystem fluxes, and soil characteristics in coastal redwood forests, Sonoma, CA. Fog water flux to the forest floor via throughfall (TF) was approximately 5 times greater at the windward (ocean-facing) edge than at sites on the interior of the patch, while rain delivery was more even across the whole forest patch. This edge effect for TF showed an exponential decline away from the windward forest edge; all sites greater than about 75 m from the edge received comparable fog inputs. Soil moisture patterns reflected the input pattern: the surface soil horizon at the windward edge had consistently greater water content than did interior sites throughout the fog season. After a large fog event, throughfall added to edge soils roughly doubled the moisture content at the soil surface. The absence of such input in the forest interior left relative water content lower by a factor of two to three compared to the edge site. While both tension and gravity lysimeters collected water at all sites in the forest during the rainy season, only tension lysimeters near the windward forest edge collected water in the fog season. These results suggest water availability at edge and interior locations can differ markedly during the fog water season and that fog may affect rates of primary production, biogeochemical cycling, and soil development.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0486 Soils/pedology (1865)
SC: Biogeosciences [B]
MN: Fall Meeting 2005