216 
GEOGRAPHICAL IMPORTANCE OF THE FOREST. 
vegetation that breeds fever, and more insidious forms of mor¬ 
tal disease, by its decay, and thus the earth is rendered no 
longer fit for the habitation of man.* 
To the general truth of this sad picture there are many 
exceptions, even in countries of excessive climates. Some of 
these are due to favorable conditions of surface, of geological 
structure, and of the distribution of rain ; in many others, the 
evil consequences of man’s improvidence have not yet been 
experienced, only because a sufficient time has not elapsed, 
since the felling of the forest, to allow them to develop them¬ 
selves. But the vengeance of nature for the violation of her 
harmonies, though slow, is sure, and the gradual deterioration 
of soil and climate in such exceptional regions is as certain to 
result from the destruction of the woods as is any natural effect 
to follow its cause. 
In the vast farrago of crudities which the elder Pliny’s ambi¬ 
tion of encyclopaedic attainment and his ready credulity have 
gathered together, we meet some judicious observations. 
Among these we must reckon the remark with which he 
accompanies his extraordinary statement respecting the pre¬ 
vention of springs by the growth of forest trees, though, as is 
usual with him, his philosophy is wrong. u Destructive tor¬ 
rents are generally formed when hills are stripped of the trees 
which formerly confined and absorbed the rains.” The ab¬ 
sorption here referred to is not that of the soil, but of the roots, 
which, Pliny supposed, drank up the water to feed the growth 
of the trees. 
Although this particular evil effect of too extensive clear¬ 
ing was so early noticed, the lesson seems to have been soon 
* Almost every narrative of travel in those countries which were the 
earliest seats of civilization, contains evidence of the truth of these general 
statements, and this evidence is presented with more or less detail in most 
of the special works on the forest which I have occasion to cite. I may 
refer particularly to Hohenstein, Der Wald , 1860, as full of important 
facts on this subject. See also Caimi, Genni sulla Importanza dei Boschi , 
for some statistics not readily found elsewhere, on this and other topics 
connected with the forest. 
