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Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/27/2004 Publication Date: 5/1/2005 Citation: Bates, J.D. 2005. Herbaceous response to cattle grazing following juniper cutting in oregon. Rangeland Ecology and Management. 58:225-233. Interpretive Summary: Juniper removal by mechanical treatments and prescribed fire has accelerated the past decade in Oregon and California, with a major goal of restoring shrub-grassland plant communities. Livestock grazing can affect post-treatment successional dynamics, but these impacts have not received adequate study, thus ARS evaluated grassland recovery in cut western juniper woodlands subjected to grazed and ungrazed treatments. The results found that (1) juniper cutting removed overstory interference and resulted in significant increases in understory cover, biomass, and seed production; and (2) grazing after cutting did not limit understory recovery with the exception of perennial grass seed production which was lower in the grazed-cut compared to the ungrazed-cut. These results imply that managed grazing may not set back restoration of native plant communities and that dominance by juniper has a far greater effect in suppressing plant community than does grazing. Technical Abstract: The rapid expansion of western juniper (Juniperus occidentalis spp. occidentalis Hook.) across the northern Great Basin the past 100 years has diminished shrub and understory plant composition and reduced forage production. Juniper removal by mechanical treatments and prescribed fire has accelerated the past decade in Oregon and California to restore shrub steppe plant communities. Livestock grazing can affect post-treatment successional dynamics, but these impacts have not received adequate study. This study evaluated herbaceous plant recovery in cut western juniper woodlands subjected to grazed and ungrazed prescriptions, over four growing seasons. The study consisted of four treatments; ungrazed cut (cut), grazed-cut, ungrazed woodland (woodland), and grazed-woodland. Stocking rates were 0.78 cow-calf pairs per ha for 5 days in the first year following treatment and 0.94 cow-calf pairs per ha for 4 days in the second year after treatment. Juniper cutting removed overstory interference and resulted in significant increases in herbaceous cover, biomass, and seed production when compared to adjacent woodlands. Herbaceous cover, standing crop, perennial grass density, and seed production all increased in the ungrazed-cut treatment compared to ungrazed-woodland. A similar level of response was measured in the grazed pasture where herbaceous responses were greater in the grazed-cut versus the grazed-woodland. These results imply that juniper cutting had a greater effect on herbaceous dynamics than did the grazing application. Grazing in the cut treatment did not limit herbaceous recovery with the exception that perennial grass seed production was lower in the grazed-cut than the ungrazed-cut. Rest or deferment is required the first several growing seasons after juniper cutting to provide plants the opportunity to maximize seed crops. |
