miller] U'lXD-BLOJiW S.LXD 49 



paratively distinct vegetation belts or zones exist in this region. 

 The facts and principles illnstrated in this specific case can be 

 adapted to other localities. 



Human Relations. 



The intiuence of a sand dune region upon man is both nega- 

 tive and positive. If a man's good farm land lies in the lee of a 

 dune area it may be entirely buried by the advancing sand, his 

 farm buildings and fences may be covered and he will be forced 

 to seek a home elsewhere. The sand area itself is of low agri- 

 cultural value and will support only a very sparse and nomadic 

 population. Further, the drifting sand is very destructive to 

 forests as few trees can survive even a partial burial and the 

 densest forest is no obstacle to an advancing dune (Fig. G). Rail- 

 roads, wagon roads, and streams traversing a dune area have 

 to be guarded constantly if thev are to remain in service. Re- 

 gions of wind blown sand, therefore, oft'er little inducement to 

 human occupation. However, dune areas if favorably situated 

 mav be very valuable. Such is the case with the dune area at 

 the south end of Lake Michigan. Here the sand is used ex- 

 tensively for railroad grading, concrete and brick manufacture. 

 The region itself is the site of many manufacturing plants, 

 towns, and cities. This value, of course, is not due to the pres- 

 ence of the sand but to the location. As previously pointed out 

 dunes may be made stable by planting them with suitable vege- 

 tation, and where the climate is favorable they may be convert- 

 ed into good pasture land and forest reserves. In general, the 

 latter is probably the most important way in which dune areas 

 can be made useful to man. 



He who knows the most, he who knows what sweets and 

 virtues are in the ground, the waters, the ])lants, the heavens, and 

 how to come at these enchantments is the rich and royal man. — 

 limcrsoii. 



