A dense young forest of firs is being 

 threatened with destruction by the sand 

 which appears to be approaching rapidly. 



The dune has stopped its forward 

 march on the forest. Numerous signs of 

 its destructive v;ork are evident. 



The sand has been blown away from 

 these Cottonwood trees revealing the 

 secondary roots formed when the sand 

 was piled several feet in depth around the 

 trunks cf the trees. 



The steep slope of an approaching 

 sand dune is shown, much higher than the 

 trees. The partly covered trees on the 

 slope are still alive. 



A forest graveyard. The dune has 

 moved on uncovering the buried forest in 

 its rear. 



Cottonwoods partly covered by the 

 advancing sand. Their growth each 

 year equals the rise of the sand. 



331 



