"Alternations of Forest Growths," is a scientific success. The information
really desired in these cases, was that imparted by Dr. Dwight in his
suggestive work of travel, in which all the incidental facts and
surrounding circumstances are fully given. It does not appear from any of
the foregoing statements, given as a specimen, that there were any
neighboring trees sufficiently near to have supplied seed for the new
forests taking the place of the old,--manifestly the most important
physiological fact connected with the whole inquiry, whether looking to
proper forest-management, or to future "schools of forestry," certain to
be established in this country, as they have been in most of the leading
countries of Europe.

It is, however, stated by Dr. Hough, in his voluminous report, that, "in
New England, the pine (without giving its varieties) is often succeeded by
the white birch, and, in New Jersey, by the oak; the succession of oak by
pine, and the reverse, in the southern states." And it is further stated,
without reference to the nature and quality of the different soils, or the
absence or presence of neighboring seed-trees, that "poplars and other
soft woods are very often found coming up in pine districts that have been
ravaged by fire." "We have noticed," he continues, "in Nebraska, ash, elm,
and box-elder following cottonwood. In the natural starting of timber in
the prairie region of Illinois, where the stopping of fires allowed, we
often see a hazel coppice; after a time the cratA|gus, and finally the
oaks, black-walnuts, and other timber. These growths are often quite
aggressive on the prairies. In Florida, the black-jack oak usually takes
the place of the long-leaf pine." In all these cases, the contiguousness
of similar, or dissimilar growths, is not stated.

He nevertheless cites a most important fact respecting the alternations of
timber growth, noticed by Sir Alexander Mackenzie, in his overland journey