What came to be a 50-year struggle to protect a portion of the Big Thicket for posterity begin in 1927 when R. E. Jackson, a railroad conductor, formed the East Texas Big Thicket Association (ETBTA) which sought to preserve . With Don Baird, of the Texas Academy of Science, the ETBTA instigated a biological survey that was conducted by Hal B. Parks and Victor L. Cory in 1936 defining the Big Thicket as a area of East Texas. With this survey and growing support of newspapers and the scientific community, the ETBTA lobbied the government for a national park. However, four national forests had recently been established in East Texas, more oil was discovered in Polk County, there was resistance from the lumber industry, and World War II brought an increased demand for lumber, all undermining their efforts. By the 1950s, the ETBTA existed primarily on paper and eventually expired. However the idea did not die. A new Big Thicket Association was founded in 1964 by Lance Rosier and continued pushing for protected land and the governor appointed Dempsie Henley to head a proposal for a state park. However, with changing officials in state elections, lackadaisical attitudes, opposition from timber firms, and several attempts without success, Henley enlisted the aid of U.S. Senator Ralph Yarborough in 1965. Yarborough was enthusiastic and introduced a bill to establish a national park in 1966. Claude McLeod, a biologist at Sam Houston State College, had been studying the Big Thicket for several years and completed a manuscript about the time a National Park survey team arrived in 1966 to develop the proposal. McLeod's research, which mapped over acres across nine counties, was used as the basis for the National Park's report. It was only after seven years and another 27 Big Thicket bills were introduced in Congress, both pro and con, that a resolution was reached. Congress passed the Big Thicket National Preserve legislation in 1974 which was finally signed by President Gerald Ford.