Behind the Barbed Wired of Manzanar: Guayule and the Search for Natural Rubber 

Famed photographer Ansel Adams visited Manzanar in 1943; most of these images of the camp (above) are from his trip. Library of Congress, Prints & Photographs Division, FSA/OWI Collection.

Few Americans gave much thought to rubber—the nation’s largest agricultural import—before Japan attacked Pearl Harbor on December 7, 1941. That complacency changed immediately, especially as the Japanese military gained control of much of the Pacific and Southeast Asia—and also the plantations, warehouses, and ships that supplied the world with rubber. With the fall of Singapore in February 1942 the United States and its allies lost access to over 95% of their supply—a supply crucial to the war effort.

In the meantime a quieter emergency had surfaced. American leaders believed Japanese Americans posed a threat to the war effort, and local authorities soon forced many of them to register with the police. Many also had financial assets frozen. In the same month that Singapore fell, President Franklin Delano Roosevelt signed Executive Order 9066, which sent more than 110,000 Japanese Americans to assembly centers, detention camps, and “relocation centers” across the West. Families had only a week or two to comply and soon found themselves crowded into hastily constructed barracks, with only a suitcase full of their personal belongings.

The United States excelled in using rubber—consuming almost 60% of existing rubber supplies. Almost all natural rubber came from Hevea brasiliensis, a tree native to South American rainforests, but by the 1930s mostly grown on plantations in Southeast Asia, in areas under British, Dutch, or French control. Synthetic rubber existed—Nazi Germany and the Soviet Union had made progress using industrial alcohol, coal tar, or petroleum by-products as feedstocks—but the United States lagged far behind in the synthetic-rubber stakes.

Suddenly, after years of quibbling, patent disputes, and political delays, hundreds of millions of dollars poured into the search for a synthetic alternative to natural rubber, which was used in everything from waterproof clothing to tires to electrical insulators. But synthetic rubber has its limitations. It lacks the elasticity and tensile strength of natural rubber, and its feedstocks were needed for other military and industrial operations. Thus, many turned to the American soil for a domestic and botanical solution to the rubber crisis. Hopes centered on guayule (Parthenium argentatum Gray), a small, woody, drought-resistant shrub resembling sagebrush, native to the elevated deserts of northern Mexico and a small corner of southwestern Texas. Guayule produces a good quantity of latex but had never become a significant commercial product. In the crisis of war could it become an American source of rubber?

The hunt for domestic natural sources of rubber began in earnest in March 1942. In its scale, urgency, and interdisciplinary scope the Emergency Rubber Project (ERP) emerged as the Manhattan Project of the plant sciences. Based in Salinas, California, the ERP collected about 1,000 American agricultural chemists, plant physiologists, geneticists, agronomists, entomologists, foresters, and agricultural engineers to solve America’s rubber emergency.

At Manzanar, the Japanese American internment camp located in the windy and dusty valley below Mount Whitney, these threads of war and dislocation came together in a small, precarious effort to create a new source of rubber.

Finding a Source, Proving Patriotism

Robert A. Emerson, an expert on photosynthesis, as well as a Quaker, pacifist, and social democrat, is at the center of much of this story. Based at the California Institute of Technology, Emerson was convinced that the internment policy was “an organized effort to reduce the Japanese to slavery.” The internees included many skilled chemists, botanists, plant physiologists, and nurserymen, and Emerson came to believe that science—specifically, producing rubber from guayule—would demonstrate that many of the Japanese Americans were “more than willing” to serve their country and contribute to the nation’s defense.

Emerson began his efforts in April 1942 just as most of the “evacuees,” as the War Relocation Authority euphemistically described them, settled into their barracks at Manzanar. He first had to persuade government officials to permit rubber research to take place at the camps, and then he had to convince Jap­a­nese American scientists and nurserymen to join the project. Significantly, he enticed his former graduate student Shimpe Nishimura to stay in the United States and eventually take over leadership of the Manzanar research.