ALTERNATIONS IN TIMBER-GROWTH. 191 



in circumference, and the white oaks 20 feet aronnd. I was struck with astonishment 

 to meet a few trees of the oak kind, considering that I had not seen any for some 

 weeks. After discovering the first few, I kept a lookout for more such places, and, as 

 well as I can remember, I found two more of the same kind, containing trees of the 

 same enormous size, but no small oaks nearer tb*n the large waters emptying into the 

 Susquehanna and Delaware. The places mentioned were near the heads of those 

 rivers, and where the streams were small. I invariably found small bodies of very 

 large hemlock trees (the prevailing timber) near these places; the remainder of the 

 trees consisted of beech, sugar-maple, with a few white walnut, white ash, birch, &c., 

 but no oak. 



In those parts of the country where the prevailing timber consisted of sugar-maple, 

 beech, and birch, I observed large trees growing, as it were, on stilts, their roots being 

 three feet above the ground, which trees undoubtedly grew on old loga that had either 

 fallen with age or had been blown down by hurricanes, and had rotted down from the 

 roots of the trees. 



The clumps of oak and hemlock are generally in the midst of or surrounded by large 

 todies of beech and sugar-maple lands, mixed with some ash, aud a few wild cherry 

 and hemlock trees. In some parts of the country, the prevailing timber is still hem- 

 lock on the sides of hills and along streams. 



From the circumstances of the great size of all the oak trees growing in the spots 

 noted above, it appears to me that most of the high country, including the headwaters 

 of the Delaware, Allegheny, and Genesee Rivers, was originally an oak country. The 

 hemlock appears to have succeeded the oak, for there is still a considerable quantity of 

 that timber over the f<ce of the country, but from the number of logs of it lying on 

 the ground, and its still visible decline, I think the beech, sugar-maple, &c., succeeded 

 the hemlock, as they are the prevailing timber at present. The timber that appears 

 to me will take the place of all others in the country befoje mentioned is the white ash 

 and wild cherry. 



Au instance is mentioned in Ohio in which a storm-track had grown 

 up with black walnut,^ and in fact examples might be multiplied indefi- 

 nitely without arriving at any definite rule of succession by which the 

 change could be previously known. These alternations of forest growth, 

 sometimes coming on gradually and at others at once, when the ground 

 is clear, have been regarded as arguments in favor of a rotation in farm 

 crops, the soil appearing to become exhausted of the elements suited to 

 the growth of one species, while becoming fitted for another. This 

 theory may still have its advocates, but it may be easier to account for 

 it by supposing that the seed is derived from neighboring trees that here 

 find a lodgment under circumstances peculiarly favorable for growth. 

 Some of them, like the poplars, and those with winged seeds, may be 

 borne by the winds to great distances, and where a heavy forest growth 

 is wholly removed, it often occurs that young plants o£ other species 

 already 'scattered here and there find their opportunity and improve it 

 before the seed of the former timber growth, if sown, could germinate. 

 The aggressive nature of the soft woods in young forests is one of the 

 plagues of forestry, and care is often needed to prevent them from 

 shading out the more valuable kinds. 



In the region around Green Bay, Wisconsin, overrun by fires in 1871, 

 dense growths of poplars and birches have sprung up and are growing 

 rapidly. 



At Clarksville, Ga., oak and hickory lauds, when cleared, invariably 

 grow up with pine. This is true of that region of country generally. 



At Aiken, S. C, the Jong-leaf pine is succeeded by oaks and other 

 deciduous trees, and vice versa. 



In Bristol County, Massachusetts, in some cases after pines have been 

 cut off, oak, maple, and birch have sprung up abundantly. 



In Hancock County, Illinois, oaks have been succeeded by hickories. 



At East Hamburg, Erie County, N. Y., a growth of hemlock, elm, and 

 soft maple was succeeded by beech, soft maple, and hard maple, but a 

 great deal more of the last named than any other. — (C. M. Hampton.) 



' Ohio Agricultural Report, 1872, p. 25. 



