When people walk or drive around Central Kentucky, many see the lush forest and fields covered in green grass, trees and bushes with beautiful splashes of color from the flowers that carpet the landscape.
Few see beyond that façade and understand an epic battle is being waged in and around Fort Knox, said Mike Brandenburg, chief of the installation’s Natural Resources Branch and a wildlife biologist.
“It’s like the Matrix for us biologists,” Brandenburg said. “We have studied these species so much that we don’t just see a forest. We see the trees and bushes and plants. We see the good in it, but we also see the bad.”
The state is home to thousands of bad plants and trees — what Brandeburg calls “invasives” — biologist have to contend with and are tracked by the Kentucky Invasive Plant Council.
When it comes to the battle, the invasive species don’t fight fair and have a leg up on the competition for survival, Brandenburg said.
An example that might shock many is Kentucky31 tall fescue. The grass seed is sold at virtually all major horticulture and landscaping shops and departments as a favorite sod because of its hardiness under sometimes difficult conditions.
It’s this hardiness that also makes it invasive, Brandenburg said.
“The reason that makes it a great grass in your yard is exactly what makes it a problem when it’s not in your yard,” Brandenburg said. “It’s a very tough sod grass with a symbiote fungus that gives it a competitive advantage.”
Even more concerning for Brandenburg and his team, though, are what he calls “exotic invasives,” species not native to the area.
“With these exotic invasives, especially the ones that pose a severe threat, there is no one-shot treatment and you’re done,” Brandenburg said. “That scenario doesn’t exist.”
The purpose of all this effort to stop the constant assault from invasives onto military lands is rooted in readiness, Brandenburg said.
“It’s important not only from an economic standpoint because forests are very valuable, but also, if we don’t do something to maintain that ecological value, they’re going to be useless for training, for missions,” Brandenburg said. “The callery pear trees for instance get so thick you can’t walk through them; and if you do walk through them, you’re going to come away bleeding.”
Biologists also have the equally important mission to protect endangered species that live on military land, species that depend on healthy prairies and forests to survive. These include plants such as pollinators, which are needed to help grow crops and reproduce healthy plants and trees, which in turn promote a healthy ecosystem for animals and other species.
“A lot of our pollinators are becoming listed as threatened and endangered,” Brandenburg said. “The reason for it is the habitats are getting degraded by these exotic invasives.”
Most exotic invasives are not only fast growing, they also are first growing.
“What you see with a lot of these exotics is that they are the first species to wake up in the spring,” Brandenburg said. “Fescue greens up early. Multiflora rose leafs out early. The privet [hedge] leafs out early; so those get a start on everything.”
Brandenburg said they took advantage of this early awakening to rid a field near Brandenburg Gate of invasive fescue while the native species slept. They did this by hitting the grass with targeted herbicides and then a prescribed burn.
“The response that we got was dramatic with all the native species that existed here,” said Brandenburg. “To have this suite of species here, some of them very important and uncommon in this setting, returning is a good representation of what Kentucky looked like 250 years ago.”
Brandenburg said a lot of government mismanagement from the past and a lack of understanding of how habitats naturally form led to the introduction of these exotic invasive species. He lists the repopulation of a forest as an example of this misunderstanding.
“A lot of people think when you go and cut a forest, you’ve got to replant it — not in a deciduous forest,” Brandenburg said. “What you are relying on is natural regeneration from the seeds. That oak tree or that poplar tree that gets cut, 99% of the time it grew from a seed.
“Regeneration in the forest is there, waiting for light, so it can grow.”
However, when invasives are introduced, Brandenburg said they typically win out.
“If you’ve got one of these exotics there also waiting, they’ll outcompete it, and it precludes you getting any regeneration of the good species,” Brandenburg said.
Brandenburg said his team has gotten very good at controlling all of these invasive species, starting with a solid plan that includes tackling exotic invasives from the outer perimeter of the cantonment area and working inward to systematically remove them.
“This is a big problem within the ecological community,” Brandenburg said. “It’s actually one of the top priorities in the Department of Defense Natural Resources Program.”
He said this active push to protect land to the tune of about 27 million acres sets the Defense Department apart from many other federal government agencies.
“The DOD is one of the smaller federal landholders, but has the highest density of rare, threatened and endangered species of any of the federal landholders,” Brandenburg said. “You’d think it would be the Park Service, or Forest Service, or somebody like that, but nah, it’s the DOD.”
Despite all the work biologists do to combat the invasives, he said the public’s help still is needed, such as resisting the urge to purchase and cultivate these exotic invasives, as charming as they may seem.
“It’s all like sticking your finger in the dike,” Brandenburg said. “After a while, you run out of fingers.”
