FIRES ON THE FLATHEAD FOREST 



IN MONTANA 



By H, H. CHAPMAN 

 Assistant Professor of Forestry, Yale Forest School 



The fact that many of the fires in 

 the west this summer were set by 

 lightning is often questioned by _ those 

 unfamiliar with western conditions. 

 But there are very few rangers who 

 have not had practical demonstration 

 of fires from this source. 



The writer was employed in the 

 Swan Valley east of Flathead Lake 

 during July and August, and can tes- 

 tify to the truth of this fact. On July 

 3, at 4 p. m., after several weeks of 

 dry weather, we had a thunder storm 

 of half an hour's duration, with_ a 

 heavy down-pour of rain. A few min- 

 utes after the storm passed, the ranger 

 called our attention to a smoke about a 

 mile off. This was located in the heavy 

 timber, and was found to be a dead 

 larch tree which had been struck an 1 

 was blazing from top to bottom. It 

 could not be cut down, so was allowed 

 to burn off and was then ditched 

 around for its whole length. No water 

 was available to put it out, and dirt 

 thrown on it did not quench it. The 

 tree burned for over two weeks, during 

 which time it was a constant menace. 

 The fire followed the roots for dis- 

 tances of 8 or 10 feet and would reach 

 the surface outside of the trench. The 

 place where this occurred was 75 miles 

 from the nearest town and only its 

 prompt discovery and constant watch 

 by the ranger prevented it from devel- 

 oping into a fire that would have 

 swept the whole valley. It had two 

 months in which to spread before any 

 rain came. 



And the fourth day after this storm 

 a heavy smoke was seen on a moun- 

 tain spur twelve miles distant. There 

 was no trail and we started the 



following morning with pack horses 

 through the timber and reached the 

 fire late that afternoon. Fortunately 

 there had been no wind that day and 

 the fire was smouldering. It covered 

 nearly two acres in a long strip where 

 the wind of the day before had blown 

 it up the shoulder of the ridge. At 

 the lower end of the burn was a dead 

 larch tree with a fresh lightning scar. 

 The location of the fire made it im- 

 possible that any person could have 

 been there for any purpose whatever, 

 and the position of the lightning-scarred 

 tree coincided exactly with the prob- 

 able center from which the fire had had 

 traveled to spread up and down hill. 

 So that while no one saw this fire start 

 from lightning as in the case of the 

 first fire, the evidence is just as con- 

 vincing. The bolt had not set this tree 

 on fire, but had ignited the dry duff at 

 its base. This had smouldered for 

 three days, and had been finally fanned 

 into life on the fourth day after the 

 storm. 



Owing to the inexperience of a fire 

 guard employed to watch this fire, it 

 broke out three times after it had been 

 completely subdued and surrounded 

 by trenches and was still burning when 

 rains came in September. It had been 

 confined to less than two hundred acres 

 in area. If allowed to run it could 

 have burned over from 20 to 100 square 

 miles. No other fires occurred in the 

 valley all summer except those set by 

 lightning. 



Fires of this character usually start 

 in some remote spot that cannot be 

 reached promptly by the ranger because 

 there is no trail and it is absolutely nec- 



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