The first three sections were originally densely wooded--the great Atlantic forest region--but farms now occupy most of the arable portions; the fourth and seventh are forestless, if not treeless, while the fifth and sixth were more or less forested--the Pacific Coast region. Floristically also, these topographic conditions are reflected, namely in the wide, north and south distribution of species, unimpeded by intervening mountain ranges, and in the change in composition from east to west. The two grand floristic divisions of the Atlantic and the Pacific forest, having but few species in common, are separated by the plains and prairies. The Atlantic forest is in the main composed of broadleaf trees with conifers intermixed, which latter only under the influence of soil conditions form pure stands, as in the extensive pineries of the South and North, and in the northern swamps and on southern mountain tops. The central region west of the Alleghanies exhibits little conifer growth in its composition, and is most widely turned to farm use. White Pine, hemlock and spruce are the important coniferous staples of the northern section, and a number of Yellow Pine species, with Bald Cypress and Red Cedar, are the valuable conifer species in the South. As regards valuable hardwoods, there is but little change from north to south. The Pacific forest flora is almost entirely coniferous, but here also climatic conditions permit a distinction of two very different forest regions, the Rocky Mountain forest being mostly of rather inferior development, and the Sierra forest exhibiting the most magnificent tree growth in the world. Nearly half the country is forestless, grassy prairie and plain, some 400 million acres being of the latter description, while open prairie and brush forest, or waste land occupies 600 million acres. Within the forest region of the East some 250 million acres have been turned into farms, leaving still two-thirds of the area either under woods, or else wasted by fire. Although any reliable data regarding this acreage are wanting, the area of really productive woodland in this section may probably be set down as not exceeding 300 million acres, which would be nearly 40% of the total area, varying from 13% in the Central agricultural States to 50% in the Southern States; Maine, New Hampshire and Arkansas being most densely wooded, with over 60%. The Rocky Mountain and Sierra forests, each with 100 million acres, would bring the total productive woodland area to a round 500 million acres, or about 26% of the whole. (Later estimates including brushlands of doubtful productive capacity, increase this area to 550 million acres.)