The islands of Japan stretch a long distance from north to south and cover a wide range of climatic zones. This results in a high diversity of wildlife despite Japan's isolation from the mainland of Asia. Japan has nine forest ecoregions which reflect the climate and geography of the islands. They range from subtropical moist broadleaf forests in the Ryūkyū and Bonin Islands, to temperate broadleaf and mixed forests in the mild climate regions of the main islands, to temperate coniferous forests in the cold, winter portions of the northern islands. About 73 percent of Japan is forested, mountainous, and unsuitable for agricultural, industrial, or residential use.