1493_ Uncovering the New World Columbus Created - Charles C. Mann [153]
For Ford, the next few years were a series of unhappy surprises. Only after the first season’s rubber trees died did the company find out that H. brasiliensis must be established at particular times of the year to thrive. Only after paying steamship bills did the company realize that it would not be possible to offset the cost of clearing all the hardwood trees on its land by selling the timber in the United States. And only after planting thousands of acres did the company learn that the Amazon has a fungus, Microcyclus ulei, that is partial to rubber trees. This last sentence is imprecise. The company did know that M. ulei existed. What it didn’t grasp was that there was no way to stop it.
At the peak of the rubber boom, Brazil sent engineer and writer Euclides da Cunha to survey its disputed western border. Lining the banks of the Purus River, an upper Amazon tributary, da Cunha found hundreds of rubber-processing facilities. (Photo credit 7.5a)
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To stoke the fires that boiled down the latex and to fuel the steamboats that took it downstream, each plant consumed huge quantities of wood—an early example of tropical forest destruction. (Photo credit 7.6)
Microcyclus ulei causes South American leaf blight. Leaf blight begins when a spore lands on a Hevea leaf. Somewhat like the potato-blight spore, the minute, two-celled leaf blight spore grows a thin, rootlike tube that extends sideways, along the top of the leaf. Usually the tube is tipped by a structure called the appressorium. Executing a right-angle turn, the appressorium drills into the inner cells of the leaf. Depending on the leaf’s defenses, the details of the infection process vary. In any case the fungus almost always wins, penetrating the leaf. Inside it produces spores—many, many spores—which emerge from new tubes on the bottom of the leaf. They are knocked free by raindrops or brushed off by rubbing against other leaves. Left behind are ruined, blackened leaves, which fall off the tree. Leaf blight defoliates H. brasiliensis. The blighted trees I have seen, with their sparse black foliage, looked as if someone had gone after them with a blowtorch. Many trees survive a bout with M. ulei, but their growth is stunted; a second or third episode will kill them.
M. ulei spores do not survive long after parting from their natal leaf. Thus Hevea trees in the wild are usually spaced widely apart; if one succumbs to leaf blight, the others are too distant to be attacked. In plantations, by contrast, trees are so close together that their upper branches are entangled. Spores hop from tree to tree like so many squirrels. Or the fungus can travel on the clothes and fingernails of plantation workers. That is what happened in Fordlândia.
Ironists will appreciate that M. ulei attacked just as Ford finally hired its first actual rubber expert, James R. Weir, a plant pathologist who was the ex-director of the U.S. National Fungus Collections. Weir’s first action for Ford was to travel to the Indonesian island of Sumatra, home to many rubber estates. Its rubber planters had found especially productive trees and learned how to propagate them by grafting wood from these trees onto sturdy rootstock. In thirty years they had created prodigious groves of high-yielding clones. Weir purchased 2,046 grafted buds in December 1933. Like the Brazilians who failed to block Wickham, the Sumatrans who didn’t stop Weir were upset about it later. Five months after his departure,