As a kid driving through the rolling roads of central Mississippi, I would stare in awe out the car window at the towering trees peaking over of the red clay below. The dense forestry and thick rocks lining the highways blanketed by a thick vegetation created a masterful display of deep green; I was dumbfounded by this plant plastering itself onto anything it could reach.
We would eventually pull onto the family land, and I would jumped out of the car and run to the edge our family built lake and pick beautiful leaves off of that green blanket to keep all to myself. Running back to my great-uncle to bestow upon him my treasures, he would laugh at me saying, “girl, you must be a yankie thinking that devil’s plant has beauty.”
That devil’s plant he was speaking of was none other than Kudzu, the great weed that ate Southeastern United State.
Originally intended to reduce soil erosion, Southern Farmers of the late 19th century were urged to plant kudzu. The plant was branded as nature’s miracle; it was going to solve agriculture, ecological, economic, and social problems. But before anyone could stop it, Kudzu spread like wild-fire. Kudzu can grow at the astonishing rate of a foot per day declaring its dominance by climbing up trees, and rocks, telephone poles, etc., and killing trees by creating a dense green cover that blocks all sunlight. Due its extensive roots system, Kudzu is nearly impossible to eradicate or contain its growth. Currently, the plant covers around 7,400,000 acres in the United States, making it appear as if the plant has been here since the beginning of time.
The featured map shows the distribution of the spread of Kudzu in the United States by county.
So what’s all the hoop-la about kudzu, this is a Climate Change blog. Well what climate change means to Kudzu is an increase of its domain over the American landscape. As atmospheric CO2 levels rise and winter temperatures increase, the vine will become more compatible with the climates of the Northern United States.
Kudzu, like other legumes, is a nitrogen fixing organism that increases and aids the nitrogen cycle by using bacteria in the plants roots to transform atmospheric nitrogen to readily available ammonium in the soil. This increased rate of ammonization, results in increased levels of nitrogen oxides that are collected by the soil.
In a study by Hickman et. al. It was found that areas infested with Kudzu have nitrogen cycle increased up to ten times faster in Kudzu based soils versus those without kudzu. And that levels of nitrogen oxide 3 were doubled. These higher levels of NOx and additionally, volatile organic compounds (VOCs) found in the soil, create the perfect recipe for ozone.
Ozone is a gas that occurs naturally in the upper layers of the atmosphere protecting the earth from ultraviolet sun rays. Ozone that is not in these upper layers of the atmosphere however is a pollutant. 4 Ozone in the tropospheric, ground level layer affects the air that we breathe, causing health concerns for everyone. This greatly affects anyone with lung issues, children, and the elderly. Additionally, higher levels of ozone can affect sensitive ecosystems, damaging plants and vegetation.
As the growth boundaries of kudzu increase due to climate change, it is allowing for additional ozone pollution to occur, affecting urban centers and regions that already have high levels of air pollutants. Additionally this increase on nitrogen and nitrification in northern soils can be detrimental to less susceptible vegetation.
It has reasonably been concluded that the northern spread of Kudzu coincides with increased NO emissions, increasing concentrations and frequency of ozone pollution. While the amount of ozone created by Kudzu is minuscule in comparison to other noxious emitters (i.e. cars), it is significant to understand this small piece of the ozone puzzle as we, as a country and individuals, seek to limit our role in climate change.
So no, we’re not all going to die tomorrow from the ozone pollution emitted by this green invader, but it is valuable to understand its effects on the climate and consequently how climate change is increasing Kudzu’s potential impact on the northern half of the United States. While great-uncle might be exaggerating by declaring this plant to be the work of the devil, it is hard to deny Kudzu’s power and domestication of the land it touches.
Slider Photo Credit: Helene Schmitz / TURN gallery
Featured Photo Credit: Invasive.org / EDDMAPS.org