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THE FORESTS OF NORTH AMERICA. 



GENERAL EBMARKS. 



The Iforth American continent, or that part of it sitnated north of Mexico, which will alone be considered here, 

 may be conveniently divided, with reference to its forest geography, into the Atlantic and the Pacific regions, by a 

 line following the eastern base of the Rocky mountains and its outlying eastern ranges from the Arctic circle to 

 the Rio Grande. The forests which cover these two divisions of the continent differ as widely, in natural features, 

 composition, and distribution, as the climate and topography of eastern America differ from the climate and 

 topography of the Pacific slope. The causes which have produced the dissimilar composition of these two forests 

 must be sought in the climatic conditions of a geological era earlier than our own and in the actual topographical 

 formation of the continent; they need not be discussed here. 



The forests of the Atlantic and the Pacific regions, dissimilar in composition in the central i)art of the continent, 

 are united at the north by a broad belt of subarctic forests extending across the continent north of the fiftieth 

 degree of latitude. One-half of the species of which this northern forest is composed extends from the Atlantic to the 

 Pacific ; and its general features, although differing east and west of the continental divide, in conformity with the 

 climatic conditions peculiar to the Atlantic and the Pacific sides of the continent, still possess considerable 

 uniformity. The forests of the Atlantic and the Pacific regions arc also united at the south by a narrow strip of the 

 flora peculiar to the plateau of northern Mexico, here extending northward into the United States. Certain 

 characteristic species of this flora extend from the gulf of Mexico to the shores of the Pacific, and while the peculiar 

 features of the eastern and the western slopes of the interior mountain system of the continent are still maintained 

 here, the Atlantic and the Pacific regions of the Mexican forest belt possess many general features in common. Ty))ical 

 North American species, moreover, peculiar to the forests of the Atlantic or of the Pacific, mingle upon the Black 

 hills of Dakota, and upon the Guadalupe and other mountains of western Texas, the extreme eastern ridges of the 

 Rocky Mountain range, and the outposts between the Atlantic and the Pacific regions. 



THE ATLANTIC REGION. 



_The forests of the Atlantic region may be considered under six natural divisions: the Northern Forest, the 

 Northern Pine Belt, the Southern Maritime Pine Belt, the Deciduous Forest of the Mississippi Basin and the 

 Atlantic Plain, the Semi-tropical Forest of Florida, and the Mexican Forest of Southern Texas (Map No. 2, 

 I)ortfolio). 



These natural divisions, although composed in part of species found in other divisions and possessing many 

 general features in common, are still for the most part well characterized by predominant species or groups of 

 species, making such a separation natural and convenient. 



The Xorthern Forest stretches along the northern shores of Labrador nearly to the sixtieth degree of north 

 latitude, sweeps to the south of Hudson bay, and then northwestward to within the Arctic circle. This Northern 

 Forest extends southward to the filtieth degree of north latitude on the Atlantic coast, and nearly to the fifty-fourth 

 degree at the 100th meridian. It occupies 10 degrees of latitude upon the Atlantic sea- board and nearly 20 degrees in 

 its greatest extension north and south along the eastern base of the Rocky mountains. The region occupied by this 

 Northern Forest, except toward its southwestern limits, enjoys a copious rainfall; it is divided by innumerable 

 streams and lakes, and abounds in swampy areas often of great extent. The nature of the surface and the low 

 annual mean temperature check the spread of forest growth and reduce the number of arborescent species, of 

 which this forest is composed, to eight ; of these, four cross to tlie Pacific coast, while the remainder, with a single 

 ex(x;ption, are replaced west of the continental divide by closely allied forms of the Pacific forest. The white and the 

 black spruces are characteristic trees of this region ; they form an oj)en, stunted forest upon the low divides of the 



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