THINNING AND PRUNING. 29 
that, m many soils, the trees should at last be unable to ob- 
tain sufficient nourishment, and should consequently thence- 
forward begin to cease to grow, and finally perish from inan- 
ition. We do not find this taking place on our rich intervales, 
and it might every where, probably, be prevented by sup- 
plies of fresh, nourishing soil. The proper inference, therefore, 
from the fact that trees are dying on the ground, is, that their 
appropriate nourishment is exhausted, and that, if the ground 
is to be continued in forest, it should be sown or planted with 
trees of some other kind. 
This is clearly indicated by what is constantly going on in 
the forests, particularly the fact which I have already stated, 
and which is abundantly confirmed by my correspondents, that 
a forest of one kind is frequently succeeded by a spontaneous 
srowth of trees of another kind. Mr. P. Sanderson, of Hast 
Whately, writes me, “There is an instance, on my farm, of 
spruce and hacmatack being succeeded by a spontaneous growth 
of maple wood.”’? Mr. Metcalfe, of Lenox, says,—‘“‘ A forest of 
beech and maple is now growing on my father’s farm, where 
stumps of white pime and some of oak and chestnut, are very 
numerous and very large.” Oaks and pines most frequently 
succeed each other. Mr. E. Swift, of Falmouth, writes,— 
‘‘Many instances have occurred in this town, of pine lands 
having been cleared of the pine timber, which has been suc- 
ceeded by a spontaneous growth of oak.” J. H. Cobb, Esq., 
of Dedham, says,—‘‘I have known pine succeeded by hard 
wood in several instances.’ Mr. S. Freeman, of Brewster, de- 
clares,—‘‘I have known frequent instances, where a forest of 
oaks has been entirely cut down, and succeeded by a growth of 
pine, and vice versa.” Mr. W. Bacon, of Richmond, writes,— 
‘‘We have seen hemlock succeeded by white birch in cold 
places, and by hard maple in warm ones; beech succeeded by 
maple, elm, &c.”” I have many similar statements from all 
parts of the State. Indeed, the Hon. D. P. King, of Danvers, 
tells me that the fact is so universally admitted, that he is sur- 
prised at my asking the question. 
This alternation is not, however, universal. In order that it 
