To the layman, John Rolfe is a nobody. To those that paid attention in history class they may know him as the man that married Pocohontas. History buffs know him as the man that saved Jamestown, with the sale of tobacco. Still some think he may be responsible for a permanent change in the American landscape. A change which stretches much further than the salty marshes of Jamestown.
Rolfe was a businessman who undercut Spanish imports by growing tobacco in Jamestown. Rolfe had brought a special strain of tobacco seed with him to the new colony. This particular strain was being grown in Trinidad and Venezuela. Rolfe brought the seeds despite the penalty of death to anyone selling these seeds to a non-Spaniard.
John Rolfe, like many other Englishmen of the time, was a smoked tobacco. Smoking tobacco was a fad brought to Europe by the Spanish, after there conquest of the Caribbean. Coincidentally the Indians in Virginia also smoked tobacco, but it was a different species which didn't agree with the European pallate. According to colonists it was poor and weak. Rolfe's tobacco on the other hand was "pleasant, sweet and strong." By 1620, ten years after settlement, Jamestown exported 50,000 pounds of Rolfe's special strain, and nearly six times that ten years later.
Because of the popularity of Rolfe's tobacco the tight waters of the Chesapeake were often crowded with empty ships ready to be loaded with the sweet stuff. To balance the weight of the ships, sailors dumped out the ballast, which was filled with mostly stones and soil. Historians believe this dirt almost certainly contained earthworms.
And little by little these earthworms would change the landscape of America. Before the arrival of the Europeans, the forests of New England and the upper Midwest had no earthworms. At least not since the last Ice Age. Without earthworms, the northern trees and shrubs would lose their leaves, which would lie on the ground and decompose their way back into the soil feeding the trees from which they dropped. The presence of worms, turns these leaf-floored forests into a more open and dry landscape losing much of their future growth. In other words, the seedlings have no protection and nowhere to root, eliminating any chance for a dense forrest. Instead an open landscape of very mature trees exists.
It is not proven that Rolfe brought the worms, but it is known that the northern forests were worm free until the arrival of the Europeans. Earthworms don't move that fast and pretty much die where they were born, so the migration of the worms from coastal Virginia to the far reaches of the United States surely takes some time to see the real effects. Perhaps another 400 years.
Thanks to Charles C. Mann and his article 'America, Found & Lost' which appeared in the May 2007 National Geographic for the information.