1476 THE STORY OF THE UNIVERSE 



touched by the hand of man; but several hundred 

 acres of exactly the same nature had been inclosed 

 twenty-five years previously and planted with Scotch 

 fir. The change in the native vegetation of the 

 planted part of the heath was most remarkable, 

 more than is generally seen in passing from one 

 quite different soil to another: not only the propor- 

 tional numbers of the heath-plants were wholly 

 changed, but twelve species of plants (not counting 

 grasses and carices) flourished in the plantations, 

 which could not be found on the heath. The effect 

 on the insects must have been still greater, for six 

 insectivorous birds were very common in the planta- 

 tions, which were not to be seen on the heath; and 

 the heath was frequented by two or three distinct in- 

 sectivorous birds. Here we see how potent has been 

 the effect of the introduction of a single tree, nothing 

 whatever else having been done, with the exception 

 of the land having been inclosed, so that cattle could 

 not enter. But how important an element inclosure 

 is I plainly saw near Farnham, in Surrey. Here 

 there are extensive heaths, with a few clumps of old 

 Scotch firs on the distant hilltops: within the last 

 ten years large spaces have been inclosed, and self- 

 sown firs are now springing up in multitudes, so close 

 together that all can not live. When I ascertained 

 that these young trees had not been sown or planted, 

 I was so much surprised at their numbers that I went 

 to several points of view, whence I could examine 

 hundreds of acres of the uninclosed heath, and liter- 

 ally I could not see a single Scotch fir except the 

 old planted clumps. But on looking closely between 



