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Tree Removal for Urban Pollinator Plots Project

A Thoughtful Approach to Improving Our Grassland Ecosystems – One Tree at a Time

Fargo Parks District, Audubon Great Plains, and researchers from North Dakota State University have partnered to establish a new project to restore prairies and grasslands in six of Fargo’s parks under the Urban Pollinator Plots Project (UPPP) as part of the Urban Woods and Prairies Initiative. Recent funding from the North Dakota Outdoor Heritage Fund has allowed this collaboration to start efforts to re-establish prairie habitat, and for many of these sites that means starting fresh. One of these sites is Forest River Park in South Fargo. Approximately five acres are being restored to prairie at this site. Currently, there are over 100 trees on these five acres, many of which are green ash trees and a declining poplar tree species. The green ash will be removed in efforts to manage Emerald Ash Borer and the declining poplars to provide more space and sunlight for the new prairie restoration.

Why do we need to remove trees?

Aren’t they a natural part of the ecosystem? Well, yes, but not for grasslands, which were historically the predominant ecosystem type in our area. A more natural grassland contains no trees and has a diverse mix of forbs and grasses. This plant community contributes to soil health and water retention, along with reducing soil erosion. When woody plants encroach and take over a grassland, soil dynamics change, biodiversity decreases, and water flow, especially in nearby riparian systems, decreases. Of course, this process is much more noticeable on a larger scale, but we aim to mimic a more natural grassland ecosystem in smaller, representative sites.

Woody encroachment is a problem in many grassland habitats throughout the U.S. and numerous studies have shown how restoration can be thwarted when woody plants are left unmanaged in grassland landscapes. Often, one particularly invasive woody species will take over a grassland patch, dramatically reducing plant diversity. Thus, a crucial part of the UPPP is to establish sites that will promote the longevity of prairie plantings, and showcase the diversity of flowering forbs within grassland ecosystems to support pollinators in our area. This cannot be done, however, when there are trees, shrubs, and snags overtaking former grassland habitats.

Grassland plants also provide habitat, food, and shelter for many wildlife species, and, of particular importance to the UPPP, pollinators. Pollinators, such as the monarch butterfly, rely on flowering forbs including milkweed and blazing star, for energy throughout the warmer seasons, and to stockpile energy to breed and survive the winter. Pollinators, including insects, bees, and bird species like the Ruby-throated hummingbird, also perform critical ecosystem services to pollinate many crop plants that provide us food. They sustain flowering plant communities by promoting their reproduction into the future. In order to have healthy pollinators, we need healthy grasslands, and healthy grasslands cannot exist with woody plants overshadowing their success. Hence, woody removal near Urban Pollinator Plots Project sites is necessary to prepare the area for prairie plantings, resulting in healthy grassland habitat.

Co-Authored by Project Partners 
Evalynn Trumbo | Research Specialist | NDSU
Torre Hovick | Associate Professor of Range Habitat Ecology | NDSU
Sam DeMarais | Forester | Fargo Parks District

References

Bach, E. M., & Kleiman, B. P. (2021). Twenty years of tallgrass prairie restoration in northern Illinois, USA. Ecological Solutions and Evidence, 2(4), e12101.

Clark, D.L., Wilson, M.V. Fire, mowing, and hand-removal of woody species in restoring a native wetland prairie in the willamette valley of oregon. Wetlands 21, 135–144 (2001). https://doi.org/10.1672/0277-5212(2001)021[0135:FMAHRO]2.0.CO;2

Fogarty, D. T., Roberts, C. P., Uden, D. R., Donovan, V. M., Allen, C. R., Naugle, D. E., Jones, M. O., Allred, B. W., & Twidwell, D. (2020). Woody Plant Encroachment and the Sustainability of Priority Conservation Areas. Sustainability, 12(20), 8321. https://doi.org/10.3390/su12208321

Limb, R. F., Engle, D. M., Alford, A. L., & Hellgren, E. C. (2014). Plant Community Response Following Removal of Juniperus virginiana from Tallgrass Prairie: Testing for Restoration Limitations. Rangeland Ecology & Management, 67(4), 397–405. https://doi.org/10.2111/REM-D-13-00147.1

Keen, R.M., Nippert, J.B., Sullivan, P.L. et al. Impacts of Riparian and Non-riparian Woody Encroachment on Tallgrass Prairie Ecohydrology. Ecosystems (2022). https://doi.org/10.1007/s10021-022-00756-7

Qiao, L., Zou, C. B., Stebler, E., and Will, R. E. (2017), Woody plant encroachment reduces annual runoff and shifts runoff mechanisms in the tallgrass prairie, USA, Water Resour. Res., 53, 4838– 4849, doi:10.1002/2016WR019951.

Archer, S. R., Andersen, E. M., Predick, K. I., Schwinning, S., Steidl, R. J., & Woods, S. R. (2017). Woody plant encroachment: causes and consequences. Rangeland systems: Processes, management and challenges, 25-84.

Ratajczak, Z., Nippert, J.B. and Collins, S.L. (2012), Woody encroachment decreases diversity across North American grasslands and savannas. Ecology, 93: 697-703. https://doi.org/10.1890/11-1199.1

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