122 



ELEMENTARY FORESTRY. 



been burned over in this way is a longtime in recovering- from 

 its injuries. Besides the injuries already cited, all forest fires 

 kill or drive out much of the game in our forests. 



Spring Fires are very injurious to trees and especially ten- 

 der seedlings for trees in the spring of the year are full of 

 sap and can endure but little heat. 



Summer and Autumn Fires generally run deep into the ground 

 and if the soil is very dry and of a peaty nature burn off the 

 roots of the trees. The result of this is that the trees are 

 blown down in great confusion and form what are 

 known as "fire falls." Where a thick growth falls, it forms 



Fipure 32. A FIRE FALL. Roots burned off and trees blown down 

 in great confusion. 



an almost impassable barrier which remains in this state un- 

 til decay and repeated fires extending over a long series of 

 years finally destroy the trees and perhaps get the land into 

 condition for a new growth. 



Causes of Forest Fires. The only natural causes of forest fires 



