TREES THAT BUILD CITIES 15 



There are whole shelves of fire extinguishers in 

 almost every tree-house of the tree cities. Let a 

 fire start to smoulder among the gutter rubbish of a 

 tree-alley, and at once the ascending smoke and heat 

 detach various leaves from the overhanging bal- 

 conies above. These, falling to the ground, explode 

 with an energetic little pop as they burn and so 

 tend to both smother and blow the fire out. Their 

 efforts, as in the human parallel, are often unavail- 

 ing, but it is worth while for them to make the 

 attempt. 



Man is the tree city's greatest enemy. With 

 his keen axe and blinded commercial eye he has ut- 

 terly wiped out millions of leafy dwelling places 

 not carefully and considerately as one who does 

 what necessity compels or one who even has his 

 eye on his own best interests, but wantonly and with 

 almost diabolical mischievousness. The result is 

 that the United States is becoming greatly alarmed 

 over its available timber supply. A little careful 

 forestry fifty or seventy-five years ago would have 

 guaranteed an adequate supply for all time. 



Through the art of sylviculture, man can estab- 

 lish, develop and even reproduce tree cities ; and this 

 he can do either by the natural reproduction of trees, 

 or by artificial seeding and planting. The demand 

 for pine flooring and other things makes it de- 



