Three-dimensional forestry is a land management paradigm developed by Japanese social reformer Toyohiko Kagawa. While studying at Princeton University, Kagawa read Tree Crops: A Permanent Agriculture by J. Russell Smith. Inspired by this book, he managed to persuade many of Japan's upland farmers during the 1930s that the solution to their soil erosion problem lay in widespread tree-planting. Kagawa also advised that they could receive further benefit if they planted crop trees, such as quick-maturing walnuts, to provide feed for their pigs.[1]
The planting of fruit and nut trees on farmland aims to conserve the soil, supply food for humans and provide fodder for animals; the three "dimensions" of his system. Kagawa was a forerunner of modern forest farming and an inspiration to Robert Hart who pioneered forest gardening in temperate climates.[1]
