The Oregon Transect Ecosystem Research (OTTER) Project was a cooperative effort between NASA and several universities to discern the ecology of western coniferous forests using remote sensing technology supported by ground observations.
Six Oregon sites across an elevational and climatic gradient were intensively studied. The transect began at the Pacific coast at the site called Cascade Head, passed through the outskirts of Corvallis, through a dense Douglas fir forest at Scio, through a mountain hemlock/subalpine fir community at Santiam Pass, through a Ponderosa pine community near Metolius, and ended at a site east of Sisters called Juniper. In all, the transect stretched some 300 kilometers west to east.
Goals of the project were to simulate and predict ecosystem processes such as photosynthesis, transpiration, above-ground production, nitrogen transformation, respiration, decomposition, and hydrologic processes; combine field, lab, and remote sensing techniques to estimate key vegetation and environmental parameters; construct a "geo-referenced" database for extrapolation and testing of principles, techniques, and predictions; and verify the predictions through direct measurements of process rates or controls on processes. A further goal of the project was to remotely sense initialization parameters and state variables for a biogeochemical-cycling, forest-stand model.
Measurements were taken using remote sensing instruments aboard satellites (NOAA-11), from instruments flown on NASA's ER-2, DC-8, and C-130 aircraft, from light aircraft, from light experimental (ultralight) aircraft, and on the ground. Field campaigns were coordinated with a Multi-sensor Airborne Campaign (MAC) during 1990 and 1991. The four 1990 data collection periods were timed to coincide with: 1) pre-budbreak at the sites (late March to early April); 2) maximum understory leaf area index (LAI), minimum starch, maximum nitrogen, and maximum LAI in the overstory (late May to early June); 3) maximum LAI and water stress (mid-August); 4) senescence of understory vegetation and reduced LAI and water stress (October). Additional data were gathered in May, 1991.
OTTER data are archived at the Oak Ridge National Laboratory Distributed Active Archive Center (DAAC) for Land Processes. Call the DAAC User Services Office at 615/241-3952 for information on how to obtain OTTER data and images.