Anyone flying over Japan is surprised at how much forest there is. Japan is heavily industrialized and one of the most densely populated countries in the world, but even so, 67% of the land is covered in forest. Of all highly industrialized nations, the only other countries with about the same high percentage of forest cover are Finland and Sweden (where the respective population densities are only around 4.5% and 6.0% of Japan's). In no other industrialized country do forests cover more than 50% of the land area.

The Japanese archipelago is long and thin, extending about 3,000 km from north to south. This creates conditions for a wide variety of trees, ranging from conifers in the north to deciduous broadleaves further south, then to evergreen broadleaves, and finally to mangrove swamps in the sub-tropical south. Forest types also vary depending on human activity. Years ago, villagers in the foothills cut firewood and removed the underbrush, and forests were later planted in those locations. In some areas deep in the mountains, natural forests still remain.

Trees also vary within a specific forest, and may change their appearance from one season to the next. In the fall, deciduous broadleaf forests paint a panorama of colors.

The forests of Japan are unique in the world, and we can think of the country as a veritable arboretum.

Why has Japan kept so much of its forest cover? Natural environment and topography are the most important reasons—the humid, temperate monsoon climate is ideal for tree growth, and the steep mountain slopes hinder land development. In the past, clear-cutting on such steep slopes easily led to floods and landslides almost every year, so the people learned through bitter experience how important it was to preserve the woodlands.

Another reason we cannot ignore is that most farmland consisted of rice paddy fields. Over the centuries, farmers and local authorities were keen to preserve the tree cover because they knew that water for rice irrigation seeped from higher ground, from under the trees.

There was also the belief that gods lived in the deep forest and among huge trees, or came down to earth in sacred woodlands. This also influenced the Japanese to preserve forests.

So the people knew that the forest was essential to production and human life. From this knowledge sprang a desire to preserve and improve woodlands, thus benefiting from the gifts of nature, one generation after another. Woodcutters developed techniques to avoid waste when cutting timber, and carpenters chose just the right piece of wood when building a house or making an everyday item. They knew the importance of using lumber in a way that was sustainable for the forest.