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P.1082 left column top paragraph: "A century ago, Schimper, the eminent German biogeographer, published his seminal book ‘‘Plant Geography upon a Physiological basis.’’ In it, he developed the thesis that the major vegetation patterns of the world were primarily determined by climate and locally modified by soils. Since the last quarter of the twentieth century, research along diverse fronts has shown that fire is also a major ecological factor influencing the nature of plants and their global geography. Vegetation fires burn across diverse climate zones from tropical grasslands to boreal forests. Satellite imagery from 2001 to 2006 revealed that nearly a third of all land area was subject to fire activity. Except in remote regions, most of these fires are ignited by people. This has led to the perception that fire is ‘‘unnatural.’’ However, many ecosystems that burn are intrinsically flammable and owe their attributes to the predictable occurrence of fire. Here, people have merely preempted lightning which was the major natural source of wildfire ignitions." |