If there's one tree species that's made the most impact in Nebraska and the Great Plains, it's eastern red cedar. Of course, eastern red cedar isn't a cedar, but a juniper.
Scientists have a couple terms for when an ecosystem is drastically changed by a newly introduced species: regime changes and state transitions. In the Great Plains, particularly Nebraska, Kansas, Oklahoma and Texas, that transition has been from grasslands to juniper woodlands.
"In the Great Plains, the leading type of state transition is grasslands transition to woody plant dominance," says Dirac Twidwell, associate professor of agronomy and horticulture at the University of Nebraska-Lincoln. "We're talking about a large-scale regime shift. When that happens, it leads to collapses of many ecosystem services we desire."
So just how have eastern red cedars impacted Nebraska?
From 2000 to 2017, Twidwell notes the number of eastern red cedars in Nebraska has doubled.
For ranchers and landowners, the impact is obvious. Twidwell says research consistently shows that as grasslands get overtaken by juniper woodlands, 75% of grazing profitability is lost.
However, the costs trickle down to a number of other sectors, such as funding for public education. As cedars expand in Nebraska, the School Land Trust, which contributes funding to public school in Nebraska, has initiated a campaign to protect grazing revenue and halt cedar invasions into Trust lands — the first of these was established in the 1980s.
The School Land Trust increased annual expenditures for cedar control by $250,000 from 2006 to 2016. Over 950,000 acres of trust land in Nebraska are grasslands that generate income for public schools from grazing leases. While necessary, these expenditures reduce trust revenue that would otherwise be distributed to public schools.
Eastern red cedars also use a significant amount of water, impacting streamflow, and using up water that would be used by other vegetation in riparian areas, which impacts waterfowl habitat.
Furthermore, red cedars pose a fire risk, notes Steve Rasmussen, northeast district forester at the Nebraska Forest Service.
"Most conifers can be quite volatile. Out West, it's more of the pine and spruces that are the problem. In eastern, north-central Nebraska, the cedar trees are the conifer," Rasmussen says. "When you have hot, dry winds, fires can get into the tops of the trees and move across the trees — what's called a crown fire. Those are impossible to stop."
So, Nebraska Forest Service has several programs, including Fire Wise and Wild Urban Interface, which provide cost-share for cedar removal to reduce fire risk and establish firebreaks.
However, managing the invasion of these trees may not be as simple as removing each tree with a skid steer. Rasmussen says complete eradication of the eastern red cedar is not a likely solution.
"Complete eradication is very difficult, just because of the number of cedars. The eastern red cedar is also a natural component of the Plains. It does have its place with the benefits it provides," Rasmussen says. "We're trying to convey the idea of utilization. The idea is utilizing those trees to help with economic value, and also offset the cost of management."
If landowners deem removal necessary, it's best to target female trees, which are berry producers, Rasmussen says. Male trees, which don't produce berries, don't have as large of crowns, and don't take up as much space or moisture.
Finding use for red cedars
Adam Smith, NFS forest products utilization program leader, notes there are other opportunities for putting red cedars to use – other than simply removing or burning them.
For example, there are also businesses that accept red cedar materials, including the central stem and log. This includes sawmills, and companies using red cedar wood to make livestock bedding. Landowners can also use them for fenceposts.
"If you have a really dense stand of trees, at that point we treat it like a forest. We pull out low-quality material, trees that have many leaders and stems. We pull out the lower-quality trees so you're left with really tall, straight, trees with few lower limbs," Smith says. "Essentially, you're leaving trees with better characteristics that could grow into saw logs or fenceposts."
There's also opportunity to combine red cedar wood chips with livestock manure to use as a soil amendment — something Smith and NFS's product utilization program are collaborating with UNL and the Middle Niobrara Natural Resource District.
"In north-central Nebraska where we have sandy soils, a three-quarter-inch rain moves through soil quickly," Smith says. "We've shown by combining wood chips and livestock manure at 6 tons per acre, you can increase soil water-holding capacity by 30% to 40% in the top 12 inches of soil, the equivalent of an extra half-inch of rain."
Part of the shifted focus on cedar management means considering the origin of red cedar seeds, Twidwell adds.
"We need to think about red cedars like most other invasive species. That means we need to think about genetics, the seed source. We need to think about how individuals spread, and start thinking about the spread of seed as a spatially contagious process," he says.
However, implementing these changes in management won't be an easy process. "We're implementing late 1800s practices still, and the system hasn't innovated much. It's time to innovate," he says. "Since Nebraska became a state, part of our pride and culture has been tied with tree planting. That makes it really hard to change."