CHAPTER XVII. 



THE INFLUENCE OF MAN. 



In such a country as Great Britain it is almost impos- 

 sible to discover any wholly natural vegetation. Man 

 has been long in possession of the soil, and has 

 practised many different methods of husbandry, whilst 

 the character of the few forests left has been entirely 

 altered, partly by the demands for timber and firewood, 

 and partly by the grazing of cattle. Even as early as 

 the times of Canute game forests, which must be con- 

 sidered of an artificial nature, were formed (Brown). 

 It follows that man's influence is a very important 

 branch of out-door Nature-study, though it has been 

 strangely neglected by most naturalists. 



The tropical forest is probably the most productive 

 part of the world's surface as regards the amount of 

 organic matter actually manufactured annually. 

 Whereas, in our own woods, it is not possible to count 

 more than three, or at the most four layers of foliage, 

 in the wet jungles of the Tropics there are almost 

 invariably four stories. These are : — {a) the trees them- 

 selves ; {b) the foliage masses of various creepers or 

 lianas ; {c) an undergrowth of small trees ; and {d) the 

 plants on the ground. In many places, the forest is 

 almost like a continuous Privet or Hawthorn hedge 

 grown to lOO feet or more in height. There are no 

 glades or vistas but a crowded mass of vegetation from 



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