WHEN forests are cleared or prairie sod busted and plowed under, the land newly prepared for cultivation may look decimated. But nature responds with great vigor to such disruptions, biologists say: The first decades in the life cycle of a forest are the period of greatest biological activity; as the forest or prairie or other prevailing vegetation type reestablishes itself and matures, the pace of renewal slows. This pattern of disruption followed by vigorous growth has shown itself in the social fabric of the United States as well. As waves of immigrants entered the US, they had to struggle to establish a place for themselves. And not alone just on the land: It was no less a pioneering task when they came to mining towns or the industrial cities of the Midwest in the late 19th and early 20th centuries, when the immigrants were mostly European. Finding threshold work at jobs nobody but immigrants would take, finding a place for a family in slum digs or on the wrong side of the tracks, children getting sent back in school because they did not know the New World's language -- this resistance demanded a greater burst of energy from the newcomers to overcome. And this energy has regularly blessed the nation the new immigrants joined.
There has always been a portion of Americans who have not welcomed the newcomers. Politically, the attitude reached its peak in the 1920s, a period of relative prosperity. The issue then was largely religious -- a backlash against the influx of Roman Catholic Europeans. At the end of that decade, Congress closed the immigration spigot to a trickle. It did not open it appreciably until the 1960s.
Today Americans are not particularly exercised over immigration, even as Congress debates immigration law reform. They are ambivalent. Surveys show that 7 out of 10 Americans think that immigrants either take jobs nobody else would want or actually increase the number of jobs available, while only about 1 in 4 thinks new immigrants take jobs away from the native population.
Nearly half the immigrants now come from Asia; 40 percent from the largely Spanish-speaking Americas. Americans are concerned that the proportion of Hispanic- and Asian-Americans may be growing too fast. But most seem to feel that the US has space enough, and its economy is growing fast enough, to assimilate the newcomers.
If there is anything to the American sense that it is at the hub of world change, it may be fitting that the preponderance of newcomers are Hispanic and Asian. Miami has become in effect a cultural and political center for the Latin American world; other American cities along the Mexican border -- and as far north as Chicago and New York -- are also important Hispanic-American centers. Similarly, the orientation of the US economy has swung sharply toward the Pacific Rim nations in recent years. That Asians are flocking to American shores appears to confirm, not contradict, the developing direction of US interests.
Most remarkable is how quickly the newcomers adopt the values of the New World, whether they originally immigrate for economic or personal or ideological reasons. This is what will be most celebrated in Fourth of July observances tomorrow.