Forestry policy in Japan shifted in the 1950s after encountering US forestry practices and concepts of resource use during the US occupation (1945–1952). Originally initiated to cope with wartime devastation and timber shortages in the postwar period, reforestation and afforestation became regarded as tools for increasing forest productivity and supporing the Japanese economic miracle by the late 1950s. In an attempt to “rationalize” forestry, the “National Forest Productivity Enhancement Plan” (国有林生産力増強計画, kokuyūrin seisanryoku zōkyō keikaku) was launched in 1957 to replace existing forests with plantations of fast-growing conifers. However, efforts to “rationalize” forestry in the areas of labor, forest ownership, and infrastructure fell short of expectations, as did the productivity of the planted forests. As resource demands were increasingly met by imports and the rural population started abandoning forestry around 1970, these plantations became a liability for Japan, especially after conifer plantations were identified as the main cause of Japanese cedar pollinosis, which has affected Japanese society since the 1980s. Forest governance and research have since struggled to address these problems, for example by developing pollen-free Japanese cedar varieties, but path dependencies created by the “rationalization” policy have remained strong.