SAND Reclamation is a matter of considerable interest to those located in the coast counties of California. As the Park Commission of San Francisco has, in the process of construction of Golden Gate Park, overcome the difficulties of sand reclamation, an account of how this has been done and of the work preparatory to the construction of the Park, following the reclamation, is probably the best way to treat the subject of this chapter.
The sand dunes of San Francisco are situated in the extreme westerly portion of the city, and, bordering on the Pacific Ocean, lie entirely open and exposed to the storms of Winter and to the Summer winds which blow nearly every afternoon during the latter season at the rate of twenty or more miles per hour.
This sand is composed of small particles of granite, clean and sharp, without any vegetable matter and having no clay or other soil mixed with it even in the smallest proportion. On account of the almost constant action of the wind, it was formerly kept ever on the move, and in heavy gales drifted like snow, at times being moved in a single day to a depth of three or four feet and often being carried a distance of over a hundred feet.
How to tie this moving mass of sand and to hold and bind it from drifting was the first problem to be solved by the Park builders.
The first experiment tried was sowing barley-seed thickly over the entire area, harrowing and cross-harrowing the sand so as to cover the seed. In due course the seed sprouted and grew to a height of several inches, covering the sand and holding it fairly well for a few months, but, on account of barley being a shallow rooter and an annual, dying out in a few months, it failed to hold the sands together after July, and the winds of August started them moving again.
The next attempt was made with the Yellow Lupin (Lu-pinus arboreus), a strong-growing, perennial shrub which is a native of this section. The seeds were collected and sown broadcast over a large portion of the area, but this proved successful only in the better protected parts of the district.
The Sea Bent Grass (Ammophila arenaria), a native of the maritime countries of Europe and successfully used in nearly all the coast countries of that continent, was next experimented with. This plant had been used in Denmark perhaps more than in any other country, but France, Holland, Italy, Spain and also Great Britain had reclaimed many thousands of acres by means of this wonderful sand-binder.
The seeds were imported from France, and, first of all, were sown in the nursery. When two years old, the plants were taken up and planted out in the sand-dime district where they immediately took root and, by their tremendous root-growth, held the sands together and prevented them from moving.
The great superiority of the Sea Bent Grass over all others recommended as sand-binders is that it is almost impossible to bury it so deeply in the sand that its crowns cannot push through to the surface. Even if buried many feet deep, it works its strong stems up to the air where new crowns form from which are sent down masses of strong, fleshy roots, anchoring the grass so firmly that the fiercest gales have but little effect on its growth.
This grass is also a wonderful sand collector. Eleven years ago, when the Park Commission of San Francisco constructed the drive facing the ocean along the Great Highway, the line of the proposed roadbed was in many places below high water mark, so sand was scraped from below high water mark in order to raise the roadway to the proper level.
When this was done, the slopes facing the ocean were planted with the Sea Bent Grass which soon took root and grew very strongly, the saline character of the sand evidently being suited to its requirements. In a few months these slopes were one mass of the strong, healthy grass with its thick, creeping, perennial roots anchored deeply in the sand.
The mass of sand is thrown up from the ocean and left on the beach by thousands of tons, and, when dried by the sun, is blown inland by the winds, being carried many miles unless obstructed.
After the construction of. the driveway, this sand, when moved by the wind, was caught by the grass planted on the slopes of the newly built road and held there, the grass pushing through the sand as it was piled up, until today there is an embankment formed by this drift-sand which is from ten to fifteen feet higher than the roadway and from a hundred to three hundred feet in width, firmly kept in position by this wonderful grass.
Eucalyptus in Sand Near Coast.
The culture of the grass is very simple. The roots are dug or pulled up by hand, and, if the ground to be operated on is reasonably level, the surface is plowed with an ordinary plow. A few of the roots are dropped about two feet apart into every third furrow and then covered by the plow, until the entire tract is thus planted. Where the ground is abrupt or too steep for plowing, holes are dug a foot deep and about two feet apart and a few of the roots dropped into each hole, the sand around the roots being pressed firm by the foot. The best season for planting is February or March although the grass will do well if planted either earlier or later in the year, provided the sand is moist. It should, if possible however, be set out during rainy weather, as at such time there is no dry sand to get about the roots; besides, the rain settles the sand around the roots far better than any treading can possibly do.
The sand-shifting having been stopped by the Bent Grass and no further trouble being apprehended from drifting, the next operation in the work of park building to be undertaken by the Park Commission was planting the ground with hardy trees and shrubs.
A great many different species of trees were experimented with, including those especially suggested by European foresters, such as the Norway Maple, Sycamore, Maritime Pine, English Yew, Austrian Pine, the Elder and many others highly recommended. In exposed situations all of these, with the exception of the Maritime Pine, failed entirely.
At the same time many of our native trees and shrubs, including Monterey Cypress, Monterey Pine, Yellow Pine as well as Alders and Maples were set out. The Cottonwood, Scrub Oak, and other varieties of Oaks were also given a trial, but, excepting the Monterey Cypress and Monterey Pine, all of them, like the hardier of the European introductions, did fairly well in the sheltered hollows only, where good soil and plenty of water were provided, while the Monterey Cypress and Monterey Pine alone stood the test of braving the storms and the blasting influence of the Summer winds in the more exposed places and the district close to the shore.
Seeds of a great many trees were also introduced from Australia and New Zealand as well as from South America, and, much to our surprise, some of these gave fine results, the Acacia longifolia and the Leptospermum proving two of the best for this sort of work, these forming a close thicket of twiggy stems which provided perfect shelter for other species not so hardy. Eucalyptus of many species were set out by thousands, but only the common Blue and the rugged Red Gum were a success in the poorer sands, and none of them could stand the climatic conditions unsheltered within five hundred yards of the salt water. The above mentioned and a few other hardy varieties grew fairly well for a period of ten years, but after that time they seemed to become bark-bound and the growth became stunted, showing that the trees, after they begin to form heartwood, require a richer soil than that composed of pure sand.
It therefore became necessary, in order to maintain a healthy vigorous growth in the young forest trees, to supply them with a foreign fertilizer. This was done by utilizing the street sweepings from the down-town streets which were brought out to the Park by electric cars, and, from these cars, distributed by carts and wagons among the starving trees. The change produced by this means was amazing. A few months after the sweepings were spread over the surface, the trees took on fresh growth and appeared to get new life and vigor, the leaves becoming darker and more richly colored.
In addition to the street sweepings, thousands of cubic yards of loam, clay, etc., have been carted into the Park each year for the formation and growth of lawns and shrubbery groups.
When the sand has been bound and prevented from drifting, a forest of strong-growing trees established (giving the required shelter), and a good soil provided, the problem of park building becomes very much the same as when the work is undertaken on a piece of land possessing naturally good soil and covered with natural trees.
On this thousand acre tract, which originally was a bleak waste of drifting, barren sand, may now be found groves of handsome trees, natives of many countries of both hemispheres, and of all the continents. Here one may see the Cedars of Lebanon and of Mount Atlas as well as the Deodars of the Himalayas, the Araucarias of Chile, Brazil and Norfolk Island, also the large-flowering, handsomely foliaged Magnolia of our Southern States, the Elms of New England, and the Sequoia, Cypresses, Pines, etc., of our own State. In addition may be found the Yews of Old England and the fragrant, feathery Acacias of Australia, together with groves of Bamboos, masses of gaily-flowered Camellias and Rhododendrons and stately Rubber trees, while hundreds of other varieties of trees and shrubs are to be seen, natives of many climes, all of them apparently happy and healthy in their new surroundings.