412 REPORT OF THE COMMISSIONERS OF 



ridge of sand is formed as high as the fence, the old fence is pulled up, or a new one 

 built on top; and so on, until a dune of the height desired is formed artificially. 

 The proper height of a protective dune is thirty-three feet. It should slope twenty- 

 five degrees towards the sea, and maybe sixty degrees on the land side. The dune 

 must be at least three hundred feet from high-water mark. After the dune has 

 reached the proper size, it is kept in shape by the sea marram (Amophila arenaria). 

 This peculiar plant, called gourbet in France, is exclusively used for fixing the sand 

 on the littoral dune. It has long, much-divided rhizomes, and will grow well only 

 when covered with fresh sand. The dune must always be kept in shape. If sand 

 accumulates in any one spot in undue amount, a draft is formed, which may end in a 

 breach of the littoral dune. Gardes cantonniers are stationed along the dune, to 

 watch it closely, and here and there on this long, straight sand-bank groups of men 

 and women may be seen digging up the gourbet in places where it is too thick, and 

 planting it where needed. Constantly the dune is watched and mended; the forest, 

 villages and fields in its lee are dependent upon it, and it in turn is dependent upon 

 the humble but persistent gourbet. 



In many instances, even where there are no encroaching dunes from the sea, but 

 where the soil is extremely unstable, it is often deemed advisable to use grasses and 

 other sand-binding plants for its fixation ; but this is now seldom done. It was formerly 

 considered necessary in Holland and France to always precede the planting of trees, 

 or the sowing of tree seed, with sand-binding grasses. At present, however, sand- 

 binding grasses are seldom used, except close to the sea on the littoral dune, where 

 it is extremely difficult, if not impossible, to start an arboreal growth. Good catches 

 of pine seed have been secured by simply sowing it on the surface. It is better, how- 

 ever, to cover the ground with brush. This is often necessary, also, in order to secure a 

 good catch of beach-grass. Direct sowings of tree seed have been successfully prac- 

 ticed in France, Holland and on Cape Cod. 



Sand-binding grasses are therefore only absolutely necessary on the littoral dune. 

 In fact, elsewhere they may be a disadvantage, in that the beach-grass is a dune 

 former. Hundreds of dunes all along our coast may be seen in all stages of formation, 

 due to the action of the beach-grass. On sandy inland soil the crab, or finger-grass, is 

 excellent. In addition to holding'the soil it yields excellent fodder. 



The greatest soil-binders on our coast are the bayberries. When a dune once 

 becomes fixed by a good growth of the bayberry, nothing short of a very severe gale 

 will uproot it. It is the most persistent sand plant on the coast of eastern America. 

 * A large number of leguminous plants will grow well on our coast, and I have often 

 thought that Lupinns perennis, the purple lupine, should be more extensively planted 

 on unstable sands. It is not the salt air or wind which limits the species along 



