At the time of European settlement, approximately 80 million hectares of forested wetlands existed in the conterminous United States (Gosselink and Lee, 1989). Although substantial harvesting of timber resources began with the coming of pioneers, drainage and clearing for agriculture were extensive by the middle of this century. By the 1950s, forested wetland had been reduced to about 27 million hectares, and by the mid-1970s to 24.4 million hectares (Gosselink and Lee, 1989). The loss rate from 1954 to 1974 was about 0.51 percent per year (Harris and Gosselink, 1990). Conversion to agricultural use has accounted for 87 percent of these wetland losses (Tiner, 1984).
One of the best-documented examples of conversion of bottomland hardwood wetlands has been on the 9.8-million hectare Mississippi alluvial plain (Figure A.12). In 1937, bottomland hardwood forests covered 4.9 million hectares of this alluvial plain, but by 1977 they had been reduced to 2.2 million hectares of natural wetlands (MacDonald et al., 1979). The greatest forest loss resulted from conversion to croplands. Currently, along the lower Mississippi River, areas of bottomland hardwood forest still are being cleared for agriculture in tracts up to 12,000 ha at a time (Gosselink and Lee, 1989). Disastrous floods of the Mississippi River in 1927 and 1929 led to massive government programs of levee construction and a myriad of other water control works. As a result of the reduced flood frequency and duration, agricultural development increased and bottomland forests were cleared for row crops such as soybeans. Other major factors include the continuing increase in urban areas and related uses.
Two of the best remaining examples of bottomland hardwood forest are the 24,000-ha Delta National Forest in western Mississippi and the 22,000-ha Tensas River National Wildlife Refuge in northeastern Louisiana (Newling, 1990). Sites representing the historical effects and current restoration and reforestation activities include (1) areas of the Yazoo National Wildlife Refuge in west central Mississippi, (2) part of the Tensas National Wildlife Refuge, (3) the Ouachita Wildlife Management Area in central Louisiana, and (4) research