CHAPTER VI
The Fixation and Plant Protection of Sand Dunes
   The technique of sand-dune fixation, like all other arts, evolved slowly. The impulse to do something must have been irresistible when dune systems broke their bounds and wandered impartially over habitations and cultivated ground, bringing disturbance or ruin in their wake. Pressure was put on the authorities, and a move made towards ameliorating the conditions both in Gascony and the Prussian Baltic in the latter part of the eighteenth century.
   At first the expedient was tried of erecting fences along the crests of the high wandering dunes with a view to retarding their progress, but this was found to heighten the crest with eventual aggravation of the trouble.
   It must have been perfectly obvious to anybody who considered the matter that relief from this plague of drifting sand was to be got only by a covering of vegetation; but the selection of the right plants to use and the tactics to be employed to ensure their establishment on highly mobile ground could only be determined by comparing the results of numerous experiments.
   It is not possible here to follow historically the gradual development of current methods, or to consider in detail the treatment found most appropriate for types of dune systems differing from one another topographically and in the incidence of mobility. All that can be done is to deal with the general principles.
   Littoral and Inland Dunes.—In most cases of extensive dune systems the supplies of sand originate at the shore, and
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