There is good news for beef producers in western states: They might not have to wait two to three years after a spring wildfire to graze cattle on federal rangelands, according to the U.S. Department of Agriculture.

Lance Vermeire, an ecologist with USDA's Agricultural Research Service (ARS) in Miles City, Mont., found that grazing within a year after a wildfire doesn't harm grass and can provide just as much forage as sites that haven't burned.

About 4 million acres of U.S. rangelands burn annually. Not all of that acreage is suitable for grazing, but millions of suitable acres do burn in wildfires every year.

The Bureau of Land Management and the USDA Forest Service generally recommend waiting up to three years after a fire before allowing grazing, based on the belief that grasses native to the dry climate of the northern prairies need that much time to recover, ARS said. However, both agencies are shifting away from that position — in large part, because of findings by Vermeire and his colleagues.

In studies, Vermeire has found that native grasses usually survive wildfires. When a fire sweeps through an area, it takes the dead plant material from the surface, but most of the plant, which is below ground, escapes long-term damage.

Vermeire and his colleagues compared the productivity of tracts that were grazed with tracts that were not grazed at a South Dakota site where a spring wildfire burned more than 10,000 acres. They found no significant differences in grass production. The cattle removed 47% of the vegetation from the burned sites, which is the average rate of vegetation removal from grazing.

The study was partially funded by the Forest Service, and the results will help guide federal policies on rangeland management.