Eastern redcedars are contributing to the spread of the lone star tick

Wednesday, December 3, 2025

Media Contact: Alisa Gore | Office of Communications & Marketing, OSU Agriculture | 405-744-7115 | alisa.gore@okstate.edu

An Oklahoma invasive species has become a haven for another problematic species, which has the potential to create a range of problems for human, wildlife and livestock health, as well as the environment.

Native to the rocky areas of eastern Oklahoma, eastern redcedar has been documented spreading through grasslands across the state, which affects rangeland quality and livestock productivity, as well as having negative impacts on water resources. According to studies, the trees spread by 40 square miles per year in Oklahoma.

Eastern redcedars use a significant amount of water, which reduces the amount of water running off into streams and reservoirs where it is needed. Not to mention, once it’s established, eastern redcedar proves to be a highly flammable fuel for wildfires.

Now, ticks, particularly the lone star tick, are also spreading statewide into western Oklahoma. Is this a coincidence? According to Dr. Scott Loss, OSU professor of natural resource ecology and management, and Dr. Bruce Noden, OSU professor of entomology, it’s not.

Noden and graduate student Jozlyn Propst found evidence that the expansion of eastern redcedar across the state into the western grasslands is contributing to the spread of ticks by creating a hospitable environment for them to thrive.

“When I first came to Oklahoma in 2014, we conducted surveys, and surprisingly, we found lone star ticks all the way out to the western border of Oklahoma,” Noden said.

Noden began asking the question of how the lone star tick — which needs a large amount of humidity — survives in the dry, western areas of Oklahoma. The lone star tick is the primary species that carries alpha-gal syndrome, a condition that causes a person to become allergic to red meat.

“I was talking to an agricultural producer in western Oklahoma, and I asked him where he would find ticks on his property, and he said, ‘Everybody knows they’re down in the cedars,’” Noden said. “It was common knowledge among cattle producers, but no one had put some science behind it yet.”

Propst said eastern redcedar creates a “humidity dome” for the lone star tick, making the area under redcedar trees moister than the surrounding environment and allowing ticks to remain alive until they can attach to wildlife.

Loss said that while they have not yet evaluated how eastern redcedar affects the ability of ticks to find host blood meals, he is sure there is a wildlife and livestock angle, where the ticks are attaching themselves to animals that frequent areas with the cedar trees.

“It could be deer, small mammals, birds or any number of animals that they are finding as resources within eastern redcedar trees,” Loss said. “You go into an arid environment like western Oklahoma in the summertime, and it’s obvious that it feels cooler and more humid during the day under redcedar trees, making it evident that the trees are changing the microclimates and habitats.”

Loss said natural resource ecology and management graduate student Landon Neumann recently published a study confirming that the microclimate of the grasslands changes with the invasion of cedar trees.

“There is certainly evidence now that areas with eastern redcedar retain moisture more consistently and return it to the atmosphere as water vapor, which is creating the new microclimates,” Loss said.

Noden, Propst and Loss are also researching the potential for tick-borne pathogens to increase due to the expansion of eastern redcedar trees.

“In addition to supporting pathogen-infected ticks, we have also found that most of the West Nile Virus-infected mosquitoes that we’ve collected have been found in cedar, so that’s another disease angle, which makes sense because the climate created by the trees would also be hospitable for mosquitoes,” Noden said.

Loss and Noden said their hope is that their research can inform property managers and landowners about the risks of not managing eastern redcedar on their property, including the risk of tick-borne disease transmission to humans and livestock.

“We hope future studies will provide an understanding of how redcedar may be central to supporting the hosts that ticks and mosquitoes are feeding on and contributing to the survival of arthropods in hot, dry areas of the state,” Noden said.