28 



EXPERIMENT STATION BULLETIN. 



CONCLUSIONS. 



There are two general plans of operation in the work of sand control. 

 The Shelter Bell or Harrier system is suitable to private owners. It may 

 be so managed as to enable the man of limited means to systematically do 

 a portion of the work each year until the whole blow area is under per- 

 manent forest cover. The Kntire Cover system calls for heavy expenditure 

 in labor and materials but has as its aim the completion of the work 

 over the whole area in a single season. 9 



In this s\s!em the need of a provision lor follow up or repair work 

 must be made. 



Fig. IS. The ei 



The poplar ;iml |<> 

 persistent crust at 

 holding the sand. 



iv marram 



d tin- i><><ly 



porary eov 



. 



(lie very 

 inplet ely 



Hand along the Michigan shores can be controlled if proper meth- 

 ods are applied. Certain plants are admirably adapted for use in estab- 

 lishing a "crust" in which other forms of tree growth must be planted 

 to insure permanent forest cover. 



By waiting for planted belts to grow into high shelters, certain ad- 

 jacent belts in the lee may be utilized by the growth of certain forest 

 crops, or orchards, but never by annual crops. 



Studies of planting done from ten to twenty years ago point out the 

 imperative need of establishing and maintaining a solid cover on the 

 windward slopes of all blows. 



Planting must begin on the windward side of a blow with the estab- 

 lishment of a facing of low forms that are capable of withstanding the 

 rough treatment to which they will be subjected. 



Tn all dune formations where 1 the sand is cast up by water a control 

 shelter* of hardy shrubs must be set as close as possible to the winter line 

 of high water and ice. An artificial barrier of drift material and wood 

 forms a splendid protection and justifies considerable expense to 

 establish it. 



