Mankind’s effect on nature hasn’t been all bad, according to visiting lecturer Charles C. Mann.
Some of the richest soil in the Amazon Rainforest is “in its entirety a human creation,” said Mann. According to Mann, through the addition of charcoal and other natural substances to the ground, Amazonian natives gradually enriched their farm lands over thousands of years.
The current untouched state of the Amazon, however, is less fertile, with less biodiversity, due to a history of deforestation. This begs the question of whether natural conditions are necessarily better than those of human intervention.
One of the problems Mann identified with movements to restore areas like the Amazon is the impossibility of drawing a baseline setting that can be unanimously agreed upon.
In Montana, plants and humans coevolved, leading to dependence of Ponderosa Pine trees on the burning cycles of Native American tribes to clear land for agriculture. Deprived of these fires, the trees cannot release their seeds. Without further human intervention now, the dominant species of the area would die out, according to Mann.
“We ignore this kind of history at our peril,” said Mann with regard to what steps, if any, should be taken to repair damaged land.
The idealized concept of American wilderness, according to Mann, is nothing like how the Eastern coastline existed for thousands of years before European settlements. From Georgia to New England, Native Americans had employed methods similar to those used in the West to tame forests for farming.
European settlers followed Columbus to the New World, bringing with them the “bacterial and viral soup” of new diseases that caused a massive drop in native population levels, said Mann, and forests took on the form we look back to today with nostalgia.
This interchange of organisms between continents is “continuing right to the present day, and is part of this ecological convulsion that we’ve been living in for so long that it’s our new norm,” said Mann.
Beyond accidental exchanges of viruses, bacteria and animals, increased globalization has led to the intentional development of certain species in foreign areas as well.
In the seventeenth century, non-native plants like maize and potatoes were brought to China, a change that converted arid lands to terraced hills for farming. These unreinforced terraces, though, usually collapse with heavy rainfall, creating extra work and an unstable agricultural zone.
The “great green wall of China” movement to replant the area, said Mann, is an attempt to reverse this “devastation that began 400 years ago.”
These efforts, however, may not be feasible. Planting hundreds of thousands of pine trees in an area of China that was naturally a desert, then forcibly converted to farmland for foreign species, means “trying to recreate an ecosystem that has never existed,” said Mann.
Most of the trees die, because the soil has few nutrients and is subject to recurrent erosion, according to Mann, who added that the flood cycles that led to the current state of the land are equivalent to “a [hurricane] Katrina per month for a hundred years.” This situation means the land may never return to its original state.
“[Sustainability] is an enormously appealing concept, but one that is very hard to wrestle with in a practical way,” said Mann. “Maybe together we can work on figuring out how to actually achieve and understand it.”
Charles C. Mann’s Tuesday night lecture was sponsored by the UMass Sustainability Initiative. Mann is an award-winning author and journalist who studies the effects of economic growth and globalization on ecosystems. Understanding this relationship, both historically and currently, can allow for more viable sustainability efforts.
Emily Bedenkop can be reached at [email protected].
