During the AFI Task Force site visit on July 6 and 7, fifteen Rhizophora mangrove plots were treated with oil, oil and dispersant, or retained as controls. During the following two weeks 15 additional plots were set up along the canal bank between and beyond the earlier plots. The new plots are identical in layout and tree composition to the original 15 plots. The plots and individual trees in each plot are being monitored weekly for stress symptoms, i.e., leaf yellowing/browning, apical bud death, and tree death. The following Table presents a summary of cumulative leaf yellowing/browning at the end of four weeks; each value represents the mean of triplicate plots. It should be noted that the literature variously indicates that the leaves of Rhizophora may remain on the tree an average of 0.7 to 1.2 years. From these values, trees would be expected to have lost somewhere in the range of 6.4 to 10.9 percent of their leaves at the end of four weeks by natural processes, independent of treatment. In addition to yellow/brown leaves, a number of trees have developed dead apical buds and some are beginning to die.