HOW FIRES DESTROY OUR FORESTS 



331 



floor for long periods, some- 

 times for eight years or 

 more. When the forest is 

 destroyed by fire the seeds 

 stored in the forest floor are 

 usually not all destroyed. 

 The sunlight and warmth 

 which reach the soil after 

 the forest is removed soon 

 cause the seeds that lived 

 through the fire to spring to 

 life, and the forest is re- 

 placed as if by magic. This 

 accounts for theyoung stands 

 found in some of the large 

 burns where no green trees 

 were left for seed trees. A 

 notable example is the well- 

 known "Yacolt burn" in 

 southern Washington, which 



combination of conditions 

 exists. Long dry periods 

 preceding a fire and a strong 

 wind accompanying a fire 

 will produce conditions 

 favorable for developing a 

 crown fire. When crown 

 fires are carried before a 

 wind in mountainous coun- 

 try the slopes facing tb< 

 direction from which the fire 

 comes will usually be com- 

 pletely burned, but patches 

 of green timber may be left 

 on the opposite slopes, or in 

 the valleys, or in moist situa- 

 tions. 



Only occasional mature 

 trees are killed by surface 

 fires, but the fire gets into 



TRYING TO COME BACK 



OCCUrred in IOX)2. Although One and two year old knob-cone pine seedlings are growing under a the bases of a number of the 



e . 1 1 if small seed tree that was killed by a fire two years before the picture . . 1 ,i 



a forest Of more than half a was taken. Such groups of reproduction disappear with the next fire. trees through CraCKS HI the 

 , Crater National Forest, Southern Oregon. . . , , 



million acres was completely bark and through pitch pock- 

 killed, this area is now clothed with a magnificent stand ets, and fire scars result through which diseases enter 

 of young growth, which sprang up immediately after the and cause rots and loss of timber. 



tire from seed that was stored in the forest floor. The These surface fires also destroy seed and cones ud 



entire forest is destroyed only when an exceptional prevent an accumulation of litter, which is the storage 



THE SOUTHERN SLOPE IS THE FIRST TO BECOME A BRUSH FIELD 



.unt of dry conditions the southern slopes suh'er more severe fires and, also, are more frequently burned. The usual condition in 

 this stage of fire destruction is shown by timbered northern slopes and brushy southern slopes. Crater National Forest, Southern Oregon. 



