Since the 1970s, Akira Miyawaki has advocated the value of natural forests and the urgent need to restore them. He considers that the 1992 Earth Summit in Rio de Janeiro failed to protect native forests and that (except very locally) they continue to decline or deteriorate.
Miyawaki observed the trees which traditionally grew around temples, shrines, and cemeteries in Japan, such as Japanese Blue Oak, Castanopsis cuspidata, Bamboo-leaf Oak, Japanese Chestnut trees, and Machilus tunbergii (a tree from the laurel family). He showed that they were native species, relics of the primary forest. At the same time, he noted that trees such as Japanese Cedar, Cypress and Larch Pine, supposedly native to Japan, had in fact been introduced into Japan over centuries by foresters in order to produce timber. Miyawaki was led to reflect on the consequences of the change in composition and sometimes structure of the majority of Japanese forests, which are now far away from their original natural vegetation.
He calculated that only 0.06% of contemporary Japanese forests were indigenous forests. Contemporary forests, created according to forestry principles, are not in his view the most resilient nor the best suited vegetation for the geobioclimatic conditions in Japan, neither are they the most suited to address climate change.
Referring to potential natural vegetation (PNV) (a concept he studied in Germany), he developed, tested and refined a method of ecological engineering today known as the "Miyawaki method" to restore native forests from seeds of native trees on very degraded soils which were deforested and without humus. Using ecological theories and the results of his experiments, he quickly and successfully restored, sometimes over large areas, protective forests (disaster-prevention, environment-conservation and water-source-protection forests) at over 1,300 sites in Japan and various tropical countries, in particular in Pacific area Restoration of Evergreen Broad-leaved Forests in the Pacific Region, in the form of shelterbelts, woodlands and woodlots, including urban, port and industrial areas.
Although most experts believe that rapid restoration of a forest is impossible or very difficult on a laterized and desertified soil following the destruction of rainforest, Miyawaki showed that rapid restoration of forest cover and restoration of soil was possible by using a judicious choice of pioneer and secondary indigenous species, densely planted and mycorrhized.
Studying local plant ecology, he uses the species that have key roles and complementary roles in the normal tree community. These species are accompanied by a variety of accompanying species (40 to 60 types of plants or more in the tropics) for "support".
"Rather than scrap them, I want to bring memory objects back to life as earth resources - for the sake of repose of souls, and for the future."