National Geographic : 1957 Oct
540 Hermann Postlethwaite, USDA Rows of Trees Shield Prairie Farmsteads from Eroding Winds and Blinding Blizzards Blowing dust threatened this Oklahoma farmland until the Federal Government launched a major tree planting program in 1934. Since then more than 300 million trees have been planted along 45,000 miles of the Great Plains. Shelter belts protect soil from wind damage for a distance 20 times the height of the trees. Cottonwood, Chinese elm, juniper, hackberry, Osage orange, and many other trees do this work well. southern pecan leaf blotch. But given warm, long summers in proper earth, the tree grows handsomely. Pecan (Carya illinoensis, also called C. pe can and Hicoria pecan) is the largest member of the hickory genus. When mature, it nor mally reaches 100 feet in height; but foresters have recorded pecans 150 and even 170 feet high, with diameters of 5 to 7 feet. Commercial orchards often use mechanical tree shakers to dislodge the smooth, brown, thin-shelled nuts. But generations of boys with bamboo canes have reached up into the trees to flail the branches and bring down sweet-kerneled prizes. Shelled, the kernels average 100 to the pound. Union Soldiers Took Pecans North The pecan was first introduced into culti vation about 1766. Early attempts to graft or bud trees were unsuccessful until a slave of the Louisiana planter Telesphore J. Roman succeeded in grafting 16 trees in 1846. After the Civil War, Union troops returned home from the South with pocketfuls of pecans, and some they planted.