WHY TO PLANT. 17 



increased, so, on the other hand, the streams 

 have often shrunk away to mere threads, so that 

 they could not be depended upon at certain 

 seasons of the year for the supply of mills, or 

 for the purposes of husbandry or navigation. 

 But we have failed until now to trace these 

 effects to their simple and sufficient cause, the 

 removal of the trees. 



The connection is easily shown. Every one 

 acquainted with the forests knows that the 

 leaves, falling from year to year and gradually 

 decaying, form a soil quite different in texture 

 from that in the open ground. It is loose and 

 spongy, and often of great depth. In the Adi- 

 rondack woods the "spruce-duff," as it is called, 

 is often four feet deep. The rain which falls 

 upon this soil does not flow off immediately, as 

 does that falling on a hill-side bare of trees, but 

 is absorbed by it, as water is absorbed and held 

 by a sponge, and oozes out gradually, flowing 

 down the slope with a steady stream or sink- 

 ing slowly into the deeper earth to reappear 

 in neighboring or more distant springs. So, 

 again, where forests crown the hill-sides in the 

 cooler latitudes, the snow which falls is screened 



