Jan., 1919] Effects of the Eruptioyi on Vegetation 



185 



ZONE OF HEAVY ASHFALL. 



We come now to the consideration of conditions in the 

 fifth zone where the vegetation, in addition to being swept by 

 the blasts already discussed under the preceding heading, 

 was deeply buried under an ashfall so heavy as to prevent 

 the restoration of an herbaceous ground cover. Concern- 

 ing the conditions of death in this area but little needs to be 

 added to what has already been said in the preceding section, 

 for the working of the added agent of destruction is so simple 

 as to require no particular exposition. 



Photograph hy R. F. Griggs 

 INJURED POPLARS IN LOWER KATMAI VALLEY. 



The branches and ordinary buds were all destroyed. The new growth has come 



from dormant buds protected by a heavy growth of bark 



on the large branches. 



Curiously enough the chief interest in this zone lies, not in 

 the death of those plants which perished, but in the circum- 

 stances surrounding the survival of the few that persist. For 

 these not only bear upon our original problem, that of reveg- 

 etation, but also throw some interesting side lights on the 

 character of the eruption. 



Inasmuch as the area near the volcano was not visited until 

 three years after the eruption, the observations concerning 

 these survivals were perforce made on plants which had begun 



