The solemn and vast forest now covering its grounds was artificially created for the shrine on the wasteland based on modern science, in accordance with the Japanese traditional notion of what the sacred residence of gods should look like. On creating this forest, there was a debate over whether to make a Japanese cedar forest or one similar to the natural forests which existed around modern-day Tokyo before the urbanization, and the latter was selected considering the air pollution and soil. Top scientists who mastered German forestry took charge of the planning, and factoring in various elements, it was planned so that on the fourth and final stage of the forest (after a hundred and several decades to two hundred years from those days) there should emerge a forest resembling a domestic natural forest and remain so eternally - though at present its transition is ongoing faster than expected.
Before the creation of the shrine there used to be 15,000 trees in the whole 700,000-square-meter (175-acre) land, but the number reached 120,000 when completed.