Page:Popular Science Monthly Volume 42.djvu/265

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destroyed. First, a breakwater or dike is constructed—occasionally a mere plank fence—against which the sand from the beach soon forms long rows of dunes. These sand-hills, usually the enemies of the land, being thus hindered from drifting inland, are impressed into the service of the land, and become its coast-guard against the invading waves. The second step is to plant them with beach grass, or some other sand-loving plant, to bind the sand together, and, by the succession of growth and decay, finally to form a soil.

"We are accustomed to regard sand as utterly barren, but the plants native to the coast sands of Prussia have been enumerated by naturalists, whose estimates vary from 171 to 231 varieties. Of these one of the most available is the Arundo arenaria (marram), which thrives only in sand and in the salt air of the beach. This in time serves to prepare the soil for larger plants.

In France 100,000 acres of dunes have been reclaimed by planting. In that country the maritime pine (Pinus maritima) has been planted with great success. It does not, however, thrive close to the sea. The ailantus, a tree common enough in our land, and certainly sufficiently tenacious of life in our streets and fields, is a sand-loving tree. I have seen an abandoned cellar choked with healthy ailantus trees, and have known them to spring up from the root after being cut down and rubbed with salt! It is probable, then, that if it will grow on the beach it will hold its own against the ocean or any other enemy.

Finally, forests, and even vineyards and pastures, cover the space once resigned to the barren sand. "Every seed that sprouts binds together a certain amount of sand by its roots, shades a little ground with its leaves, and furnishes food and shelter for still younger or smaller growths. A succession of a very few favorable seasons suffices to bind the whole surface together with a vegetable network, and the power of resistance possessed by the dunes themselves, and the protection they afford to the fields behind them, are just in proportion to the abundance and density of the plants they support."—Marsh.

To return to our own country: It is said that the dunes of Michigan thirty years ago were clothed with trees, where now the sands are constantly shifting, and the lake beach changing with the action of wave and wind, while the lake level grows lower year by year. The sands of Cape Cod were formerly covered with beach grass, whortleberry bushes, and a peculiar species of dwarf oak. Dr. Dwight, in his Travels, speaking of a beach in Massachusetts, says:

"Within the memory of my informant the sea broke over the beach which connects Truro with Provincetown, and swept the body of it away for some distance. The beach grass was immedi-