Japanese colonial environmentalism in early twentieth-century Korea is examined with special reference to academic representations of hwajeon or shifting cultivation. Tracing the progress of the project for the disposal of hwajeon and the accompanying researches in forestry, geography, and agronomy, the author discovered that there was an intricate but strong relationship between the scientific discourses and colonialism in the name of conservation. After the Japanese annexation of Korea in 1910, the colonial foresters began to map the condition of the forest areas and to exclude the shifting cultivators in order to save the woody lands from them since these cultivators had apparently destroyed the Korean natural environment from the southern area up to the north for centuries. The disposal project mobilized academic researchers in geography and agronomy and was revised by them in the 1920 s. Hwajeon was found to be more systematic and stable than the foresters had supposed but was definitely represented as a destroyer not only of timber but of the national land itself and then a subject of “improement” in the 1930 s. The serial mapping and researches had a critical influence on the manner of understanding and treatment of the indigenous agriculture, although some of the Koreans and also Japanese considered it to be a debatable issue.