IMPROVEMENT OF THE FORESTS. 19 
Nature points out, in various ways, and the observation of 
practical men has almost universally confirmed, the conclusion 
to which the philosophical botanist has come from theoretical 
considerations, that a rotation of crops is as important in the 
forests as it is in cultivated fields. A pine forest is often, with- 
out the agency of man, succeeded by an oak forest, where there 
were a few oaks previously scattered through the wood, to 
furnish seed. An oak forest is succeeded by one of pine, under 
the same conditions. But it frequently happens that there are 
not enough trees of the opposite family to seed the ground: in 
which case a forest will be succeeded by another of the same 
kind, which, though it will grow, will probably not flourish 
with the same luxuriance as would one of another family. 
It will not be considered foreign to our purpose to enumerate 
some of the more important of the objects which should be kept 
in view, in the cultivation and extension of our forests, and the 
native and foreign trees best suited for those purposes. 
The first want, as has been shown, is fuel. The trees best 
suited to the purpose are the hickories, the oaks, the beech, the 
birches, the maples, and the pines, particularly the pitch pine, 
and the chestnut and hemlock for close furnaces. If fuel is to 
be used in the form of charcoal, the hard woods only are of 
great value, particularly chestnut, the birches, alders, oaks and 
maples. As materials for house-building, the pines, the spruce 
and the hemlock are generally employed. White oak was 
formerly used for frames, and in many houses now standing for 
more than a century, it has not begun to decay. Chestnut 
resists decay, and is more and more in use. F'loors are some- 
times made of beech, of birch, and of ash. ‘The best materials, 
probably, are oak, white pine, chestnut, and spruce. 
For ship-building, oak is considered absolutely necessary, as 
being preferable to any other wood. ‘The best kinds are white 
oak, and black, or yellow bark oak. Much southern oak is 
now used. The English oaks, which, in Great Britain, are pre- 
ferred, may be cultivated here as successfully as our own oaks. 
In the construction of most of the ships of Europe, great quan- 
tities of larch are used. This tree might be profitably planted 
on thousands of acres which are now unproductive. Small ves- 
