Due to these great variations in climate, four climatic regions being differentiated, the forest flora of Japan almost rivals in variety that of the United States, with over 200 deciduous, and more than 30 coniferous species of size (besides a large number of half-trees), although not more than some 50 or 60 are of silvicultural importance, and not more than 10 or 12 species form the basis of forest management and of the lumber trade, which requires some two billion cubic feet annually, and supports an export of over six million dollars. The value of the total cut was, in 1907, placed at over 17 million dollars, of which six million was to the credit of the State Treasury.
In the tropical districts, bamboos form the main staple; in the subtropical region, the most densely populated and hence also almost forestless, the broadleaf evergreens, especially several species of oak, furnish desirable fuel wood, and two species of pine are most valued for timber, one, the Red Pine (P. densiflora) extending its realm rapidly over waste areas; camphor tree and boxwood furnish ornamental wood.
The region of temperate forest furnishes, out of over 60 species, some 14 conifers and 19 broadleaf trees of value, the former mainly of the cedar tribe, with Chamaecyparis obtusa and Cryptomeria japonica the most widely used, while of the broadleaf species, which occupy more than 50 per cent. of the forest area, Zelkowa keaki, of the elm tribe, a chestnut, a beech, several oaks, a walnut, and an ash count among the most useful.
Spruce, Fir, and White Birch are the trees of the northern forest.
Mixed forest forms 45%, broadleaf 25%, conifer 21%, and 9% is rated as blank or thinly stocked.
The forest area, which, over the whole, covers, with the addition of the newly acquired island of Saghalien, 67% of the land area, or around 75 million acres (11⁄4 acres per capita), is quite unevenly distributed according to topography and population, being mostly confined to the mountain ranges and hills which form the backbone of the country, and to the northern provinces, which contain still large, untouched areas. Hokkaido, which was opened up to colonization only 35 years ago, now with a population of only 20 to the square mile, has 63% of forest, 15 acres per capita; the northern part of Hondo has a somewhat greater area per cent., mostly on the high steep mountains, but only 1.2 acres per capita; on the southern portion, the low ranges of hills and valleys the forest area has been reduced to 53%, but shows only three-quarter acre per capita; and Okinawa, with 26%, and less than one-third acre per capita, shows the lowest.
Of this forest area, however, almost one-half is “hara,” brush forest, chaparral, or dwarfed tree growth—the result of mismanagement, excessive cutting and fires—and in the southern districts, impenetrable thickets of dwarf bamboo, which crowd out tree and even shrub growth wherever such mismanagement gives it entrance. These extensive haras are cut every two or five years for the brush, which is used to cover and furnish manure for rice fields.
Fire, which, until lately, ran over 5 or 6 million acres annually, and ruthless cutting, have in the past and are still deteriorating the forest area.