190 1.] FORESTRY. 7 



question whether or not removal of our forests will per- 

 manently injure our atmosphere and render it less fit for ani- 

 mal use than it now is. We look about us, and up into space, 

 .and are struck by the small room which we mortals require, 

 and we learn that so rapid is the atmospheric diffusion that 

 but little if any difference can be detected between the air 

 of a forest, or of the desert of Sahara, or the air over a vast city, 

 and our fears are allayed. 



But, on the other hand, it is said that a no less distinguished 

 scientist than Lord Kelvin has seriously raised this very ques- 

 tion. He points to the fact that the oxygen of the air seems to 

 be a fixed quantity, and that plant life is, if not the only pro- 

 ducer of oxygen, at least the most active one. He leaves the 

 conclusion where I will, to you. 



These are some of the outlying considerations of forestry. 



Would it be wise to give our cleared fields over again to 

 forests? Not at all. Forestry is nothing if not practical. 

 The reason why I have devoted twenty years of my life to this 

 work in my native State is because I have seen one-sixth of its 

 area changed by removal of the timber, from a productive to 

 an unproductive condition, and I desire to see it made pro- 

 ductive again. If your acres pay you in farm or garden crops 

 better than they would in any other crop, then you would be 

 most unwise to make any change. But, perhaps, your land 

 may vary in quality, and some of it may compensate you for 

 your agricultural operations, and some of it may not; what 

 are you to do with that which does not pay you to farm? 

 Clearly, it ought to produce something in return, at feast, for 

 the taxes which you pay upon it. 



I admit that the most valuable timber is of slow growth, 

 and that if you depend upon this it must be as a legacy to 

 your children. We have in Pennsylvania two laws which, 

 however, turn such land into an immediate source of profit if 

 planted in timber. They are as follows: 



An Act for the encouragement of forest culture, and providing 

 penalties for the injury and destruction of forests. ' 



Section i. Be it enacted, etc., that in consideration of the 

 public benefit to be derived from the planting and cultivation 

 of forest or timber trees, the owner or owners of any land in 

 this commonwealth planted with forest or timber trees in num- 

 ber not less than twelve hundred to the acre, shall, on making 



