USES OF THE FORESTS. 



USES OF THE FORESTS. 



1. Forests create or gradually but constantly improve a soil. 

 The roots penetrate deeply into the ground, and thus let in the 

 air to produce its slow but sure effects. The radicles decom- 

 pose the grains of sand, and extract from them some of the 

 elements essential to a soil; they drink in moisture and the 

 carbonic acid which has been formed beneath, or brought down 

 from the atmosphere above, the surface ; and from these several 

 elements, acted on by heat, light and air, in the leaves, and by 

 that unknown influence, vegetable life, are formed the various 

 substances which compose the plant. The annual deposit of 

 leaves, and the final decay of the branches and trunk, go to 

 constitute the mould upon which other plants grow. And the 

 soil thus formed is kept by the thick matting of the roots from 

 washing away. 



An unprotected hill soon loses its soil. Every rain bears 

 away a portion, till it becomes a bare rock, and the slow pro- 

 cess must recommence by which rock had been originally con- 

 verted into soil. That process takes place slowly on all uncov- 

 ered rocks, but far more surely and rapidly under cover of 

 trees. There also the invisible sporule, borne thither on the 

 wind, perhaps, from a distant continent, attaches itself to the 

 naked rock and vegetates ; encrusting its surface with a lichen 

 which gets thence a foothold and an alkali, while it lives on 

 the atmosphere. From the thin layer left by its decay, another 

 species springs, which in turn gives place to mosses and herba- 

 ceous plants. Whoever has climbed Monument Mountain in 

 Stockbridge, has had an opportunity of observing this process 

 in its different stages and circumstances. On the projecting 

 cliffs of white quartz, of which the mountain consists, the beau- 

 tiful lichens which paint its sides have made no more progress 

 than if the mountain had been thrown up two years ago. They 

 are spread upon it as thin as paper, and perfectly fresh. 

 Wherever they decay, the violence of the rain and winds 

 washes them clean off, and the work is begun each year anew. 

 But in the protected crevices, and under shelter of the few trees 



