Hardwood Encroachment of Oklahoma Rangelands
Rangelands are home to a variety of plant and animal species. The populations that live on rangelands provide sustenance for millions of people. Rangelands are found all over the world and make up about 51 percent of Earth’s land surface (Bloomfield 1). Open grasslands around the world are becoming increasingly populated by woody plants, shrubs, and trees, a process that is expected by experts to continue in future. Climate changes are partly responsible for this phenomenon. Droughts, rainfall pattern changes, and increased CO2 levels all have an impact on these ecosystems. Reductions in the frequency and intensity of fires that have historically marked such regions have also contributed to encroachment of woody plants.
This is particularly true in Oklahoma, where encroachment of eastern red cedar (Juniperis virginiana) and ashe juniper (J. ashei) on rangeland has become a major problem. A 1985 Soil Conservation Service survey showed that by 1985 3.5 million acres in Oklahoma had been invaded by these woody plants, up from 1.5 million acres in 1950 (Engle, Bidwell, and Moseley 1). Ecosystem-invasive plants like the eastern red cedar and ashe juniper have an impact on the quality of rangelands and their ability to sustain biodiversity.
A 1994 survey conducted by the Natural Resources Conservation Service reported that eastern redcedar and ashe juniper were present in all but 9 counties in the state of Oklahoma (Engle et al., 1). In agreement with the survey a decade before, the 1994 survey showed that concentration of red cedar occurs in a large portion of the northwestern part of the state and that some populations have coalesced whole areas between rivers. Ashe juniper was shown to occur mainly in the south central Oklahoma region and in the Arbuckle mountains. Results of this survey also showed that the red cedar populations are moving eastward along the main river...