2M THE PRINCIPLES OF HANDLING WOODLANDS 



Crown fires occur when the woods are verv dry, and 

 when there is a high wind. Without a strong wind a 

 crown fire is seldom started, and even if the crown of an 

 individual tree is ignited, a fire does not usually spread 

 and run through the crowns on a still day. Before a 

 high wind, a crown fire spreads with great velocitv, tak- 

 ing at once a V-shaped form with a distinct front or 

 head. This head may be only from SO to 100 feet wide, 

 but in the case of the largest fires its width may be very 

 great. In the case of the larger fires the front is gener- 

 ally carried forward by a series of heads. The head of 

 the fire burns very rapidly through the crowns, and there 

 follows closely a surface fire burning with the same rapid- 

 ity. There are well-developed wings, where the fire 

 runs through the crowns on each side of the head. 

 These, in turn, are accompanied by surface fires, while 

 spreading out on the skirts are w ider surface fires, eating 

 out diagonally with the wind and covering a broader area 

 than the crown fire. 



The strong draft of heated air arising from the fire 

 carries up with it an immense quantity of burning cin- 

 ders and pieces of bark. The wind, in turn, carries this 

 material far in advance of the main fire-head, and thus 

 innumerable new surface fires are started. This gives 

 rise to the popular idea of a spontaneous starting of fires 

 in advance of a crown fire. 



An ordinary crown fire does not run more than 2 or 

 3 miles an hour, although undoubtedly the great con- 

 flagrations of the north woods, such as the famous Hi nek- 



