growing at various points along its track, was mainly beech, maple, birch,
ash, hemlock, spruce, etc.; but it was rarely replaced, at any point, by
the same timber, in the growths that almost immediately followed. The
trees that are now growing along the track of the tornado are principally
poplar, cherry, birch, and a little beech and ironwood: no ash, maple,
spruce, or hemlock, except here and there, at considerable intervals, a
tree or two which may have been replaced by natural seed. The important
fact noticeable, in this connection, is that the aggressive timber--that
replacing the old--entirely usurped the place of the evergreen growths,
supplanting them with those that were wholly deciduous. Besides, it does
not appear that the poplar, the cherry, and the ironwood, which were
altogether aggressive, previously grew near enough to the track of the
tornado to have possibly supplied the seed necessary for their appearance
and growth.

The fact was specially noticeable at the time, and has been widely
communicated since, that the white oak timber cut off at Valley Forge for
fuel and other army purposes in the American camp, in the winter of
1777-78, was succeeded by black oak, hickory, chestnut, etc.--the white
oak entirely disappearing, although by far the most favorably situated for
propagation by seed. But the alternations of forest growths had attracted
too little attention at that time to render the meagre facts given of any
special value to scientific men. If the usurping timber had grown in the
immediate neighborhood (a fact not stated), it might have come from
natural seeds, and not from primordial germs under "favoring conditions."

In the Ohio Agricultural Report of 1872, an account is given of a
storm-track, in that state, which swept for a considerable distance, and
was violent enough to bear down all the timber before it. It is stated
that the path of this tornado (which must have occurred many years ago)