370 THE EFFAGEMENT OF NATURE BY MAN 



the ships which now frequent the island. The further 

 progress of destruction will be carefully and minutely 

 observed and recorded but not arrested I 



It is, however, in cutting down and burning forests of 

 large trees that man has done the most harm to himself 

 and the other living occupants of many regions of the 

 earth's surface. We can trace these evil results from more 

 recent examples back into the remote past. The water 

 supply of the town of Plymouth was assured by Drake, 

 who brought water in a channel from Dartmoor. But the 

 cutting down of the trees has now rendered the great wet 

 sponge of the Dartmoor region, from which the water was 

 drawn all the year, no longer a sponge. It no longer 

 " holds " the water of the rainfall, but in consequence of 

 the removal of the forest and the digging of ditches the 

 water quickly runs off the moor, and subsequently the 

 whole country-side suffers from drought. This sort of 

 thing has occurred wherever man has been sufficiently 

 civilised and enterprising to commit the folly of destroying 

 forests. Forests have an immense effect on climate, 

 causing humidity of both the air and the soil, and give 

 rise to moderate and persistent instead of torrential 

 streams. Spain has been irretrievably injured by the 

 cutting down of her forests in the course of a few hundred 

 years. The same thing is going on, to a disastrous extent, 

 in parts of the United States. Whole provinces of the 

 Thibetan borders of China have been converted into un- 

 inhabitable, sandy desert, where centuries ago were fertile 

 and well-watered pastures supporting rich cities, in conse- 

 quence of the reckless destruction of forest. In fact, 

 whether it is due to man's improvident action or to 

 natural climatic changes, it appears that the formation of 

 "desert" is due in the first place to the destruction of 

 forest, the consequent formation of a barren, sandy area, 

 and the subsequent spreading of what we may call the 



