UNL Researchers Study Seed Production of Eastern Red Cedar

Released on 05/26/2004, at 2:00 AM
Office of University Communications
University of Nebraska–Lincoln
Lincoln, Neb., May 26th, 2004 —

University of Nebraska-Lincoln researchers from the Department of Agronomy and Horticulture completed a seed study to determine how the eastern red cedar (Juniperus virginiana L.) expands into mixed-grass prairie. Susan J. Tunnell, James Stubbendieck, Julie Huddle and Jennifer Brollier announced their results in the spring 2004 issue of Great Plains Research.

"Because eastern red cedar has become a serious ecological problem in the Great Plains, understanding its seed dynamics and establishment from the seed bank can help manage and reduce its expansion," Stubbendieck said.

The researchers sampled the soil seed bank underneath and surrounding eastern red cedar trees at two mixed-grass prairie sites in Nebraska. Their objectives were to investigate the seed bank for seed number and viability in various directions and distances from existing trees. "We found that most seeds were recovered inside the canopy, and seed numbers rapidly declined as distance from the canopy increased," Tunnell said. "Our results indicate that the eastern red cedar does not rely on long-term accumulation of seeds."

Studies by other researchers have shown that the negative ecological implications of increased eastern red cedar densities on grasslands include a decrease in plant diversity. Eastern red cedar will establish in undisturbed old fields and pastures of the eastern United States but is eventually replaced by hardwood trees. However, in the undisturbed grasslands of the Great Plains, eastern red cedar becomes the dominant woody plant and eventually develops into an eastern red cedar forest.

The authors concluded that to reduce the number of future seedlings, it is necessary to remove female cone-bearing trees. The number of annual seedlings appears to be dependent on the current year's seed production and avian dispersal, not on the existing seed bank. Therefore eastern red cedar expansion in the grasslands could potentially cease after the seed source has been removed.

Great Plains Research, a journal of social and natural history, is published by the Center for Great Plains Studies at UNL. The journal is available for purchase from the Center at (402) 472-3082.

Susan J. Tunnell, Post-doc Research Assoc., Agronomy and Horticulture, (402) 472-1953; and James Stubbendieck, Professor, Grassland Ecology, (402) 472-1519