Page:Popular Science Monthly Volume 89.djvu/213

 Popular Science Monthly

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��The entire coast-line was fringed by a fence consisting of posts driven in the ground at close inter\als, and llie spaces between tliem were interwoven with willow branches and brush. Soon the strong winds blowing in from the ocean banked a great wall against this fence and eventually it was entirely covered with sand. Then a second line of fence was erected on the small lateral dune thus created. In time this fence was co\ered by the sand which banked up against it. This operation was repeated

��The sand menace has disappeared, and it cannot return.

The situation on the Pacific ("oast is similar in one respect to that which confronted France. The sand is blown inland by the high winds from the ocean. The situation on the Atlantic Coast is just the opposite, however. There the sand is blown seaward, by winds coming from the land.

In the Columbia River region the sand is much lighter in weight than the sand of the Atlantic Coast, due to the

���Sand dunes about L _

��many times and then other means of increasing the size of the dune were used. Native grasses that thrive in sandy soil were planted along the top of the dune; this served to keep its height as uniform as possible by preventing the winds from carving indentations in the face of the pile. Pine trees were planted along the top. These served to check the wind-blown sand as the fences had done in past years, and day by day the dune grew in height and widensd out. As it increased in size more pine trees were planted.

To-day a great forest 2,500,000 acres in extent fringes the coasl-linc as the result of this initial experiment. It represents France's greatest supply house of turpentine and lumber. The countr\- King inland from it is rich antl fertile.

��large quantity of mica which it contains. This makes it easily carried by the wind. It also gives it great fertility when once watered, so that with the reclamation of the sand dunes there are possibilities of cultivating profitable orchards and farm lands in connection with the belts of forest which will necessarily have to be established.

Many dunes in the lower Columbia River valley are more thanthirt\- feet high, and several even more. The accompany- ing photographs illustrate some of the prolilems caused b\' the dunes. Rail- roads have spent thousands of dollars in rough fences, known as hurdles, in an effort to keep their tracks from being submerged. Irrigation ditches have been moved from time to time to prevent th?m from being filled with sand.

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