DISTRIBUTION OF FORESTS IN UNITED STATES. 29 



variable in meaning, or more liable to mislead in statistical reports, 

 when taken as the basis of estimate for ])raetical results or business 

 use. In the Northern States, if applied to deciduous trees, we find it to 

 include a mixture of various species and of all ages, with every degree 

 of kind, density, and value. If of evergreens, there may be great uni- 

 formity of size and kind in a given district, but not comparable with 

 others having a different soil and climate. In the South, the term, 

 besides including densely timbered tracts, applies to thinly timbered, 

 grassy pine barrens, and to swamps with every grade of value. In the 

 Western and Southwestern States, it may include scattered oak open- 

 iugs or dense forest, as the case may be; and on the Northwest coast, the 

 upland valleys densely crowded with a grand and lofty timber growth. 



Generalizing in the most comprehensive way, the whole region east of 

 the treeless belt, abounds in species of the hard-wood, broad-leaved, de- 

 ciduous genera, which in number of kinds and of individuals, far exceeds 

 those of the evergreen or coniferous classes. West of the treeless belt, 

 the conifers prevail, and the forests are made up almost wholly of this 

 family. The exceptions are relatively few, and no forests of deciduous 

 timber-trees occur in this region in sufficient amount to form great for- 

 ests by themselves.' 



The distribution of forests is, in considerable degree, influenced by 

 the underlying geological formations, as furnishing the soil and chemi- 

 cal elements upon which character the of the vegetation must depend. 

 From the kind, distribution, and size of timber-growth, the practiced 

 observer is enabled to judge with reasonable accuracy concerning the 

 nature of the rock-formation under the soil, without actually seeing it 

 exposed.^ 



1 Prof. William H. Brewer, of Yale College, iu an article published in Walker's Sta- 

 tistical Atlas, estimates the number of species of woody plants in the United States at 

 800. Of these, upward of 300 indigenous species attain the height of 30 feet, of wbich 

 250 are abundant somewhere, or at least, not rare. In this he excluded all smaller trees 

 that never attain a heigbt of 50 feet, and the tropical species found on the extreme 

 southern border. Of large trees somewhat abundant, he estimates 120 species, of 

 which 20 grow 100 feet ; twelve, 200, and perhaps five or six, 300 feet iu heigbt or np- 

 ■ward. Of these 120, about fifty belong to the coniferse. Only a very few species occur 

 across the whole country, from'the Atlantic to the Pacitic. Of these, the aspen {Populus 

 tremuloicles) and some of the cottonwoods are mentioned ; but as a rule, there is a 

 marked contrast between the frest regions east and west of the treeless belt, the tim- 

 ber of the Rocky Mountains belonging to the western rather than the eastern type. 

 New England, originally ail wooded, has 80 to 85 species, of which about 60 grow to a 

 height of 50 feet. The Middle States, also originally wooded, have 100 to 105 species, 

 of wbich 65 to 67 sometimes reach a height of 50 feet. Tbe southeastern part, also 

 entirely wooded, has over 130 species, 75 of which grow 50 feet or more, and perhaps 

 a dozen, 100 feet. The southwestern region was characterized by dense forests and 

 open plains, and numbers 112 to 118 species, of which 60 to C5 grew to 50 feet. The 

 northwestern region is diversified by prairies, "openings," forest, (some of great 

 extent and density), and timber belts along the rivers and streams. It contains 105 to 

 110 species, about 68 to 70 of which grow to 50 feet. 



2 Professor Newberry, in his Geological Survey of Ohio (i. 528), notices several in- 

 stances of this relation between rock formations and timber-growth. The Cuyahoga 

 shales, rich in potash, bear a growth of large elms, scattered over this plateau as far 

 as the eye can reach; beech and maples, with thick groves of chestnut where the 

 broken rock comes near the surface, mark the horizon of the conglomerate, and above 

 this a belt of forests, in which the predominate timber is oak, defines with great 

 accuracy the limits of the coal-measures in the northern part of Ohio. The redwood 

 of California is limited to a peculiar sandstone formation, and the noble red cedars of 

 Tennessee to the Glade Limestone, a subdivision of the Trenton Group, which extends 

 superficially as a very irregular ring across the central part rf the State. On subse- 

 quent pages we shall have frequent occasion to notice this dependence of forest 

 growth upon the underlying geological foiniations,iniludiDg, of course, the soils result- 

 ing fi4)m their decomposition. These peculiarities, when understood, afford valuable 

 indications that may be followed with profit in attempting the cultivation of timber 

 trees. 



