THE NORTHERN HARDWOOD FOREST. 3 



The term "northern hardwoods" will be used for all stands in this 

 region in which one (or more) of the characteristic species listed on 

 page 7 predominates; for though the type possesses a general uni- 

 formity of composition sufficient to distinguish it from other impor- 

 tant northern forest types, it varies greatly in different regions. 



There are two hardwood forest types that are not considered in 

 the bulletin, although the species which belong to them are often 

 found scattered through the northern hardwood forests. These are 

 the type of the dry sandy plains, in which the chief hardwoods are 

 oaks of various kinds, mixed with hickories and in the east with 

 chestnut, and the type of the swampy places, in which the charac- 

 teristic hardwoods are black ash, red and silver maples, willows, and 

 alders. The swamp type is not of great extent or importance, and 

 the other type is so much more characteristic of the South that it 

 might be considered only a northern extension of a southern type. 



GEOGRAPHICAL EXTENT. 



The northern hardwood forest (fig. 1) is found in greater or less 

 abundance within the drainage systems of the St. Lawrence, the 

 Great Lakes, and the upper Mississippi, as far south as southern 

 Minnesota ; throughout northern New England, and southward along 

 the northern and southern Appalachian Mountain ranges to extreme 

 northern Georgia. In the North it merges into the spruce and fir and 

 the aspen and birch forests of Canada. Along its southern and lower 

 altitudinal borders it shades into the great "central hardwoods" 

 forest of the Ohio and Mississippi Valleys. In the West it gradually 

 gives place to the prairie of the Great Plains region. On the uplands 

 the " oak openings " supplant it in large measure, until these, too, give 

 way to the prairie. Just how large an area is occupied by northern 

 hardwoods is difficult to estimate. It probably amounts to over 

 50,000,000 acres, nearly half of which is in the Lake States. The 

 decrease in the total forest area of the Lake States and the north- 

 east — once practically equal to the entire land area — to 60 per cent 

 in New England, 43 per cent in Michigan and Wisconsin, and 35 per 

 cent in New York and Pennsylvania, 1 has undoubtedly been greatest 

 in the softwood forest. 



TOPOGRAPHY AND CLIMATE. 



Topographically the northern hardwood region separates into two 

 very distinct" parts — the eastern mountain ranges and the rolling, 

 glaciated land about the Great Lakes. 



The eastern mountain ranges extend from southern Canada south- 

 west to northern Alabama and Georgia. The climatic conditions 

 suitable for the best growth of the northern hardwoods prevail at 

 minimum elevations of from 500 feet in northern New England to 

 1,000 feet in southern New England and the Adirondacks and 3,500 



1 Forest Service Circular 166, " Timber Supply of the United States," by R. S. Kellogg. 



