THE RELATION OF FORESTS AND FOREST FIRES 395 



losses of immense importance, the deterioration of the soil, the 

 destruction of the young growth, and the loss of the. increment 

 which a healthy young forest would have been laying on year 

 by year. The latter may commonly amount in a pure forest to 

 several hundred board feet per acre each year. With further 

 study a more exact statement of the grand total of the loss will 

 be possible ; but even now it is safe to assume that for the nation 

 as a whole the loss is represented yearly by a sum much in ex- 



A SI.ASHlNli NEEORE THE FI RE - 



L'HE MASS OF DEBRIS IS TOO THICK TO PERMIT REPRODUCTION • 

 WESTERN WASHINGTON 



cess of $50,000,000. That figure sufficiently proves that the 

 destructive action of fire on the forest in its relation to human 

 needs is a subject of the first interest and importance ; but in the 

 present paper this brief reference must suffice. The regulative 

 action of fire on the forest is here- more directly in question. 



Fires determine the presence or absence of forest in a given 

 region far more generally than is often supposed. A very large 

 part of the prairie regions of the United States is treeless prob- 

 ably because of fire. Such evidence as we have points strongly 



