Trees, please

Woods as a source of awe and spirituality

Woods were mankind’s earliest temples, and trees pointed the way to heaven.  Wooded mountains held spiritual mystique, for the abode of the gods was shielded by a forest of leaves.  As a country of forests, it’s no wonder that trees have played a prominent part in Japan*s spirituality.  Naturalist Kevin Short here provides some interesting facts about the country’s situation, and how the environment has been disastrously affected in modern times by a rapacious desire for profit over ecology.

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NATURE IN SHORT / Japan is one of the most densely forested countries on Earth
Kevin Short / Daily Yomiuri Columnist

One of Japans thousands of sacred trees

Japan is certainly a land of trees and forests. Even today, 68.5 percent of the national land is covered with forest. This figure is third behind Finland (72.9 percent) and Sweden (68.7 percent), and over twice the world average of 31 percent. An estimated 1,000 species of woody plants live in Japanese forests, which is about the same as the figure for all of North America.

One reason for the amazing diversity of Japanese trees can be found in geologic history. The Japanese islands were almost completely free of ice during the last glacial period. In contrast, until 10,000 years ago much of northern and western Europe was covered by glaciers up to a kilometer thick.

Geographical conditions also help support sylvan biodiversity. With warm oceans currents flowing on both sides, the Japanese archipelago is blessed with a mild, wet climate that is ideal for tree growth and forest development. In addition, the islands stretch a long way in the north-south direction, and climatic zones range from subtropical in the Ryukyu Islands to subarctic in parts of Hokkaido.

Botanists understand and document plant diversity using a formal taxonomic system. Trees are first divided into two major groups, gymnosperms and angiosperms, based on the type of flower and fruit. Gymnosperms include all the trees we normally call conifers, and angiosperms the ones we think of as broad-leaves. Some trees, such as the ginkgo, however, have wide leaves but are actually gymnosperms.

The vast majority of Japan’s native tree species are broad-leaves, and most of the nation’s natural forests are dominated by broad-leaves. The general idea is that angiosperms, which sport a more advanced flower structure, enjoy a competitive advantage over gymnosperms. All else being equal, angiosperms will thus tend to monopolize favorable environments, leaving the gymnosperms to get by in marginal habitats such as deeply shaded valleys and exposed ridges.

Sacred ginkgo

But today, as anyone traveling around Japan can verify at a glance, the hills and lower mountainsides in most areas of the country are totally dominated by conifers. In fact, a full 40 percent of the nation’s forests are pure stands of conifers. These are not natural forests at all, but commercial timber plantations.

In many prefectures, however, this figure is well over 60 percent; it’s even higher on hills and lower mountainsides surrounding the major cities. In late February and early March, immense clouds of yellow-green sugi [cryptomeria] pollen dust float down onto the urban areas, like some amorphous monster out of a kaiju science fiction movie. The number of people suffering from sugi pollen allergy is estimated at over 20 million.

Most of these sugi plantations were established in the years following the Pacific War, when demand for lumber for rebuilding the destroyed towns and cities was high. Entire hillsides and even watersheds were stripped bare of their diverse natural broad-leaved forests, and completely replanted in tight rows of sugi. Several decades later, however, tariff reductions made cheap imported lumber products widely available, and the price of sugi wood dropped dramatically. As a result, many plantations have since been abandoned as commercially unworkable.

Cryptomeria is a truly magnificent tree, and properly thinned and managed sugi plantations form a valuable wildlife habitat of their own. The sheer extent of the plantations, however, has placed Japan’s magnificent natural broad-leaved trees and forest ecosystems in grave danger of extinction.

A pair of Yakushima cedars "Mother and child"