LINCOLN, Neb. (AP) – Trees that suck up sunlight and groundwater at the expense of other prairie plants are creating new headaches throughout the Plains, including Nebraska, western Iowa and the Dakotas.
The eastern red cedar tree spreads so quickly that it catches many landowners off-guard, consuming huge areas of productive ranchland and threatening many of the area's original prairies. At one point in Nebraska, the trees expanded at a pace of nearly 40,000 acres a year – an area roughly half the size of Omaha – until conservationists joined forces with local ranchers to conduct more brush-clearing burns.
Conservationists call it a "green glacier" that started in Texas and Oklahoma and swept north across the Plains into Kansas, Nebraska, western Iowa and the Dakotas.
"It gets worse every day," said John Ortmann, a rangeland ecologist in Ord, Neb., who has worked with conservation groups to thin the eastern red cedar population. "Some people say, 'Wait until it's a problem.' That's like saying, 'I'm not going to change my oil until the engine blows up.'"
The trees traditionally survived on steep, north-facing slopes in canyons where prairie fires couldn't reach. But then settlers started using them as windbreaks and doused wildfires, and birds further spread the trees by eating seeds, then excreting them while perched atop power lines.
The trees are native to the Plains but they can grow so thick that many animals can't use them for shelter. They tower over smaller native plants and grasses, sucking up all sunlight and groundwater and turning prairie grass into barren patches of dirt. Without native grasses, water runoff increases and erodes the soil.
"The land becomes absolutely worthless," Ortmann said. "Once they've grown up, they take everything on the prairie. You can have hundreds of different kinds of plants, or you can have cedar trees. You can't have both."
In western Iowa, conservationists worry about the tree encroaching on the Loess Hills, an ecosystem with some of the state's few remaining prairies.
"It's a constant management issue," said Lindsey Barney, an Oakland-based district forester for the Iowa Department of Natural Resources. "I'd say we're all concerned about it in western Iowa. These prairie remnants (in the Loess Hills) aren't the last ones in the state, but they're of a very high quality."
Barney said she considers the tree valuable in forested areas and as a natural windbreak. But in prairies, she said the tree can quickly dominate the landscape.
In Nebraska, the trees have been spreading quickly and reducing the number to pre-2000 levels would cost an estimated $100 million, said Adam Smith of the Nebraska Forest Service
Removing the trees can cost as much as $2,000 an acre in states like Oklahoma and Texas, where they've spread out of control. Clearing them in Nebraska can reach up to $200 an acre, conservationists said, but the cost is likely to rise as they proliferate.
The trees also produce highly flammable needles and resin, and were partly to blame for massive wildfires that burned city-sized swaths of land in Nebraska in 2012.
"It's such a slow, benign progression, until one day you wake up and half your ranch is gone," said Pete Bauman, a range field specialist at South Dakota State University. "It's a huge problem for ranchland. Once the trees get to a point where you start to recognize they're a problem, they're much more difficult to control."
Bauman said landowners don't always realize they have a problem and fail to act before the trees are large and much harder to remove. Ranchers are most reluctant in parts of the Dakotas, which haven't yet seen a full outbreak.
Ranchland dominated by the trees typically loses about 75 percent of its profitability, said Dirac Twidwell, a rangeland and fire ecologist at the University of Nebraska-Lincoln.
The trees muscle out forage and grasses on which cattle graze. Reducing the amount of grasslands could also cut into K-12 public school state aid, which comes in part from leases on state-owned grasslands, Twidwell said.
"Because we're a grassland state, the consequences of the cedars are profound," he said.
Landowners in the Plains have formed landowner "burn cooperatives" to clear the trees before they spread out of control.
"It's definitely a problem," said Ed Hubbs, a volunteer with the Tri County Prescribed Burn Association, which works mostly in Lancaster, Seward and Saline counties in Nebraska. The trees "certainly take up resources and physical space as well, not just water and nutrients."
Hubbs, of Lincoln, said the trees become much more difficult to burn the larger they become, forcing crews to use chain saws or burn larger fires.
The prescribed burns are intended to prevent the trees from becoming as widespread as they are in Oklahoma and Kansas, said John Erixson, deputy director of the Nebraska Forest Service. Erixson said the trees are most prevalent in the eastern two-thirds of Nebraska, but they're now encroaching on the state's Sandhills, an ecologically fragile area of grass-covered sand dunes.
The eastern red cedar tree created major headaches for Robert Dutcher, who spent about three years removing hundreds of trees that spread over his family's property near Greeley, Neb. Some trees were 12 feet tall with 14-inch-thick trunks by the time he removed them.
"It just turns into a forest if you don't take care of them," Dutcher said. "It happens quicker than you think."
