Forest Conditions. 397 



The first three sections were originally densely 

 ■wooded^ — ^the great Atlantic forest region — but farms 

 now occnpy 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 re- 

 flected, namely in the wide, north and south distribu- 

 tion 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 influ- 

 ence of soil conditions form pure stands, as in the ex- 

 tensive 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 con- 

 ifer 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 Eed 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 Eocky Moimtain 

 forest being mostly of rather inferior development, and 

 the Sierra forest exhibiting the most magnificent tree 

 growth in the world. 



