Enduring Roots: Encounters with Trees, History, and the American Landscape

Chapter 5. Returning Natives

C H A P T E R F I V E retur ning nat i v es LEAF: THE MAIN PHOTOSYNTHETIC ORGAN OF MOST GREEN PLANTS. . . . THERE ARE USUALLY A GREAT NUMBER OF LEAVES ON ANY ONE PLANT, ALTHOUGH THESE MAY BE LOST IN THE COLDER OR DRIER MONTHS IN DECIDUOUS PLANTS. Stephen Blackmore, The Facts on File Dictionary of Botany My sister is telling me a story. It is about a woman who moved east from the prairie, following the prevailing winds. The woman, my sister says, felt confined. She could never get used to our eastern hills. She is telling me this story because I have just made the woman’s journey in reverse, traveling against the wind, but with the flow of American history . Though mine was only a short stay, I tell my sister that it is impossible to be on the prairie for any time at all without understanding what the woman means. Some have compared the prairie to the ocean: a long unbroken vista with the gentle wavelike motion of the tall grass moving in the wind. Others , and I am among them, find that ‘‘it is hard for the eye to wander from sky line to sky line, year in and year out, without finding a resting place!’’1 And, perhaps most famously, when Major Stephen H. Long was sent in 1820 to present-day Colorado on an unsuccessful search for the source of the Platte River, he designated Colorado’s eastern plains the ‘‘Great American Desert’’ on his maps—maps that were then incorporated in school texts so that generations of Americans ‘‘grew up believing the high plains did indeed resemble the sandy Sahara’’2 —and he deemed the region ‘‘uninhabitable by a people depending upon agriculture for their subsistence.’’3 Long’s reports were echoed. The explorer John Charles Frémont called Colorado’s plains a ‘‘parched country,’’ and the Vermont lawyer Thomas Farnham described the region as a ‘‘scene of desolation scarcely equaled on the continent.’’4 The particular eastern Colorado grasslands that the three men and Long’s botanist, Edwin James, found so ‘‘tiresome to the eye and fatiguing to the spirit’’5 are what we now call shortgrass prairie. The shortgrass is one—along with tall-grass, mixed-grass, California grassland , Palouse, and desert—of a vast network of grasslands that originally covered almost 40 percent of the United States. They are our largest 21. Charles Sprague Sargent, The Silva of North America, vol. 7. (The McLean Library, Pennsylvania Horticultural Society, Philadelphia) biome—a term used by ecologists to describe a habitat created by shared vegetation and climate—and one of our most endangered: ‘‘an estimated 99 percent of the tallgrass prairie east of the Missouri River has been destroyed.’’6 Of the four major biomes covering the earth’s surface—grassland, desert , forest, and tundra—grasslands are the largest. When the acreage of the North American prairies is combined with other corresponding patches of grassland—theRussiansteppe,SouthAmericanpampas,Hungarianpuszta, and the South African veld—grasslands account for 24 percentoftheearth’s vegetation and include the plants ‘‘which have contributed the germ plasm [or DNA] for the principal human food crops.’’7 Among these are wheat, barley, oats, and rice (the first two weredomesticatedabout10,600yearsago in the Middle East). So it is not that the prairie is, or was, unproductive. The American prairie , for example, once provided forage for a herd of bison estimated to number around 50 million (compared with today’s ‘‘45.5 million head of cattle in the ten states that were the main area of the original bison range’’).8 ‘‘Most of the productive, arable lands in North America,’’ according to botanist Phillip L. Sims, ‘‘were once grasslands.’’9 As Long told his men when they joined in an Independence Day toast on July 4, 1820, they were camping where ‘‘imagination only’’ had ‘‘traveled before.’’10 And their imagination—and mine—was shaped, or some might say limited, by the eastern forested landscape. The great divide that separates the prairie from the forest is water. Although the staggering diversity and adaptability of plants means that there will always be exceptions to any rule, tree growth is generally limited by two conditions—cold and moisture. Trees need 15 to 20 inches of annual precipitation and a frost-free period of around fourteen consecutive weeks. The American prairies were once covered by an inland sea...