METEOROLOGICAL IMPORTANCE OF FOREST, 
139 
Effects of Destruction of the Forest. 
The pbysico-geograpliical effects of the destruction of the 
forests may he divided into two great classes, each having an 
important influence on vegetable and on animal life in all their 
manifestations, as well as on every branch of rural economy 
and productive industry, and, therefore, on all the material 
interests of man. The first respects the meteorology of the 
countries exposed to the action of these influences ; the second, 
their superficial geography, or, in other words, configuration, 
consistence, and clothing of surface. 
For reasons assigned in the first chapter, the meteorological 
or climatic branch of the subject is the most obscure, and the 
conclusions of physicists respecting it are, in a great degree, 
inferential only, not founded on experiment or direct observa¬ 
tion. They are, as might be expected, somewhat discordant, 
though certain general results are almost universally accepted, 
and seem indeed too well supported to admit of serious question. 
proved by the character of the wood found in bogs, is not unfrequently 
such as to suggest the theory of a considerable change of climate during 
the human period. But the laws which govern the germination and 
growth of forest trees must be further studied, and the primitive local 
conditions of the sites where ancient woods lie buried must be better 
ascertained, before this theory can be admitted upon the evidence in ques¬ 
tion. In fact, the order of succession—for a rotation or alternation is not 
yet proved—may move in opposite directions in different countries with 
the same climate and at the same time. Thus in Denmark and in Holland 
the spike-leaved firs have given place to the broad-leaved beech, while in 
Northern Germany the process has been reversed, and evergreens have 
supplanted the oaks and birches of deciduous foliage. The principal de¬ 
termining cause seems to be the influence of light upon the germination of 
the seeds and the growth of the young tree. In a forest of firs, for in¬ 
stance, the distribution of the light and shade, to the influence of which 
seeds and shoots are exposed, is by no means the same as in a wood of 
beeches or of oaks, and hence the growth of different species will be 
stimulated in the two forests. See Berg, Das Verdrdngen der Laubwdlder 
im Nordlichen Deutschland , 1844. Heyer, Das Verhalten der Waldbaume 
gegen Licht und Schatlen , 1852. Staring, De Bodem ran Nederland, 1856, 
i, pp. 120-200. Yaupell, Om Bogens Didvandring i de DansTce Shove, 
1857. Knorr, Studien icber die Buchen - Wirthschaft , 1803. 
