You have to love the optimism of the 1800s. There was nothing people thought they couldn’t do, including irrigating the entire United States by strategically setting fire to parts of it.
For three decades in the 1800s, the United States government tried to plant trees. They wanted to plant them in a wide swath, stretching from the top of the nation to the bottom, preferably west of the best stretches of farmland. If implemented today, this plan would probably be a method of carbon capture, or maintaining topsoil, but it was the 1830s, so the plan was to plant and maintain the trees only to periodically set fire to them.
This plan was hatched by James Pollard Espy, known on both sides of the Atlantic as the “Storm King.” He had some prescient theories, like the idea that clouds form from rising columns of humid air. His burning forests plan was the product of one of his less-prescient ideas. He believed that huge fires could create rain. It’s true that, because they throw both moisture and particulate matter on which the moisture can condense up into the atmosphere, some fires do create what’s known as pyrocumulus clouds. Still the effect isn’t big enough or sure enough to control the weather. Espy’s plan would mean setting fire to county-wide or state-wide stretches of pre-planted forest to create rain clouds which would move east to irrigate the states. He believed that he could water farm states according to a precise schedule, like houseplants.
Espy’s plan was probably too big to be implemented, even if the government had approved it, but that’s not why it was blocked. By the 1840s, people had the idea that the United States was edging towards war. The southern states weren’t wild about an idea that would allow the Federal Government to control their weather, so the plan fell by the wayside.
[Source: Rain, by Cynthia Barnett]