Page:Popular Science Monthly Volume 52.djvu/484

466 under existing conditions to continue the present forests by judicious cutting and care of the young growth, it will be impossible to reforest the lands if the present method of lumbering and pasturing and the annual forest fires are continued. Where the rainfall is limited to a few weeks or months, the only water available for forest growth during the remaining portion of the year is that held in the soil by the presence of the forest cover. The experience of all who have attempted to start young trees in the open, semiarid country has been that, unless artificially watered during the dry season, the young trees die under the influence of the scorching sun and hot, dry winds.

As the result of a personal inspection of a considerable portion of the Sierra forest reserve of California, I am fully convinced that the preservation and development of the agricultural interests of the great wheat and fruit districts west of the range depend largely upon the preservation and increase of the forest covering of the region whose drainage is tributary to the agricultural areas. The same is true of the Los Angeles and San Bernardino areas of the southwestern portion of the State. Where the forest and brush have been removed, either by fire, cutting, or pasturage, the slopes are dry and dusty, the water flows off almost as rapidly as it falls, and carries along with it a load of sand and gravel to be deposited in the irrigation ditches and over the fields of the lowlands.

A comparison of such a denuded area with an adjoining forested or brush-covered district shows at once that the forest covering must be preserved if the water supply is to be stored by natural means for irrigation.

Of the influence of sheep pasturage on reforesting there is a difference of opinion among men acquainted with the forest reserves. In the semiarid region the struggle for existence is so great that all vegetation needs and must have the advantage of every condition at all favorable to its growth, if it is to grow at all. If the herbage and seedlings are destroyed by pasturage and the tramping of the sharp hoofs of sheep, the fate of the future forest growth and storage of water is settled, and its destruction foreordained. In the well-watered sections of Oregon, Washington, north Idaho, north Montana, and perhaps the Big Horn Mountains of Wyoming, the effect of pasturage of sheep would be very slight, as the growth of vegetation is rapid and luxuriant; but in the Sierra and southern reserves of California and similarly conditioned areas the damage is great, and even the pasturage of cattle in many localities will be detrimental. As soon as the reserves are carefully and intelligently studied by practical foresters, I think it will be found that each reserve has peculiar conditions that must be considered before