584 PHYSICAL GEOGRAPHY. 



procnmbcns, will very soon find places. Of shrubs, the cherry will be 

 the first; but, in places where there is still some vegetable substance 

 left, these will soon be succeeded by a growth of poplar and white birch. 

 In more southern latitudes, the shrubs and trees that spring up in burnt 

 districts are entirely different. 



When the entire vegetable substance of the soil has been burned, the 

 process by which the woods are reproduced is long and complicated. 

 Lichens and mosses then first cover the ground, and, by slow degrees, 

 flowering plants appear. Among the first shrubs, especially on moun- 

 tains and on sandy plains, there will be some species of the blueberries. 

 On Percy peaks, where years ago everything except the rocks was con- 

 sumed by fire, the vegetation can now be seen to increase year by year 

 from the base upward. A few examples will show the contrast which 

 appears between the primeval forest and that which succeeds it. If we 

 ascend Mt. Washington by the railway, when we are above the limit of 

 the trees, if we look westward, we shall see that in the valley of the 

 Ammonoosuc there is a growth of deciduous trees that extends on 

 either side far up the side of the mountain ranges that border the val- 

 ley. Some forty years ago a destructive fire destroyed the primeval 

 forest of spruce and fir ; and now in all this tract the principal growth 

 is the paper birch. Besides this, however, there is the yellow birch, and 

 now and then a poplar; and, as a new growth, we find the original occu- 

 pants of the soil. In some parts of the town of Success, the only growth 

 now is poplar; and elsewhere there are places where there have been 

 so many successive fires, that blueberries, mosses, and lichens are the 

 only growth. 



The bare ridges and mountains west of the Saco show that the veg- 

 etable matter in the soil even has been consumed, so that it must be 

 many years, even if there are no fires, before enough will accumulate, 

 from the decay of lichens and mosses, for any vegetation whatever to 

 grow, except the very lowest forms. On the line of the boundary be- 

 tween New Hampshire and Quebec province, where in 1845 tne trees 

 were cut, making an opening in the forest four rods wide along the en- 

 tire northern boundary of the state, in general, where there was a hard- 

 wood growth, it was soon reproduced, but, in places particularly where 

 there was a growth of coniferous trees, the cherry at first predominated ; 



