Page:Tree Crops; A Permanent Agriculture (1929).pdf/352

 ually grew less as the distance from the windbreak increased. The total gain was about equal to the amount of grain which could have been grown on the shaded ground near the trees. The season in which the measurements were taken was not of high winds nor did it lack moisture. It would appear, therefore, that in a windy year when evaporation was high the total gain for the field would much more than balance the loss." This statement ignores the value of wood or crop produced by the trees of the windbreak.

That means that Illinois, Iowa, Kansas, Nebraska, Minnesota, the Dakotas, and other states and other similar regions in other continents need to have thousands and tens of thousands of miles of long rows of trees. Perhaps they might be fruit- or nut- or bean-yielding trees while stopping the wind and making wood. "Alfalfa grows almost to the base of honey locust trees."

From Maine to Kansas and from Minnesota to Texas and Alabama there is much land which is uncultivated because it is threatened with overflow from some flooding stream at some time during the growing season. Therefore, the plow crops are unsafe and cannot be depended upon. Therefore, this, the best of land, usually remains in pasture. From Ohio and Iowa southward and southwestward this is the homeland