Choking ecosystems, releasing carbon from the soil...In the dictionary next to the definition of "invasive species", they could show a photo of kudzu. Nothing seems to stop it: Above you can see it growing over trees in Atlanta, Georgia. Since it was first introduced to the U.S. at the Centennial Exposition in Philadelphia in 1876, it has been swallowing the country from an epicenter in the South-East at the rate of about 50,000 baseball fields per year, occupying an estimated 3,000,000 hectares today. Kudzu can grow up to 60 feet per season, or about one foot per day.
Kudzu is extremely bad for the ecosystems that it invades because it smothers other plants and trees under a blanket of leaves, hogging all the sunlight and keeping other species in its shade. It can also survive in low nitrogen areas and during droughts, allowing it to out-compete native species that don't have those superpowers. The only other plants that can compete with kudzu are other invasive species, so that doesn't really help...
The great kudzu invasion all started out with a mistake: The Soil Erosion Service and Civilian Conservation Corp intentionally planted it to control soil erosion in the state of Pennsylvania. It was then used in the South East to to provide shade to homes, and as an ornamental species.
But as you can see in the map above, the result is more like a fast-growing cancer than anything else. How can you get rid of a plant that covers around a quarter of the country?
As if that wasn't bad enough, kudzu also screws with the soil's ability to sequester carbon, thus contributes to climate change.
In a paper published in the journal New Phytologist, plant ecologist Nishanth Tharayil and graduate student Mioko Tamura, of Clemson University, show that kudzu invasion results in an increase of carbon released from the soil organic matter into the atmosphere. Tharayil and Tamura investigated the impact of a kudzu invasion in native pine forests. (source)
This is probably because kudzu's organic matter degrades a lot more easily than what it replaces (like organic matter from trees).
The most Earth-friendly way to fight kudzu seems to be with goats, but it would take quite a lot of them to get through all the kudzu in the U.S... But if you need to deal with invasive species and don't have goats, you can conveniently rent a herd, as we've written about before with Rent-a-Goat.