INJURIOUS INFLUENCE OF THE ELEMENTS. 135 



thrown upon forest soil of the former sort readily com- 

 municates fire to its surroundings. The smouldering 

 sparks eat through the dry vegetable mould, attack the 

 scant grasses and mosses and make so much headway 

 that the green leaves of the young conifers are soon invaded. 

 The least breeze will fan the smouldering mass into 

 flames which spread rapidly to the tops of the larger 

 trees, and are then beyond control. 



Happy if you discover the fire when it is still confined 

 to the inflammable material on the surface soil. All that 

 is necessary then is to have some energetic men with 

 rakes, brooms and shovels to rake the grasses, leaves 

 and other ignitible substances, scattered over the forest 

 soil, several yards ahead of the fire towards the burning 

 mass, so that all litter and other combustible material in 

 front of the fire is accumulated into a wall. It will nob 

 be difficult with a sufficient force of men to put out with 

 their shovels and spades the approaching flames and con- 

 fine them to the raked-up wall. 



Much more difficult is the task of stopping a forest- 

 fire after it has reached the branches of the larger trees 

 and is running up to the tree-tops. Unless a heavy rain 

 sets in the only means for putting the fire out is to make, 

 at a proper distance ahead of the invading fire, a broad 

 passage in such manner that the trees standing there are 

 felled and thrown towards the advancing fire. As this 

 work takes much time while forest-fires make quick 

 headway, the opening in front of the fire should be begun 

 at such a distance from the fire that the felling is fin- 

 ished before the flames reach the margin. Otherwise the 



light the accumulated leaves and other ignitible material, as dry heather, 

 mosses a. s./., it is customary to guard against this danger by safety- 

 strips, formed by not-coniferous trees that are planted along the line of 

 railways, as for instance birches, oaks, poplars, etc. Besides the ground 

 of these strips is always kept clean of dry leaves, litter and other com- 

 bustible material. 



