We have a natural gem hidden in Roseville: A historic open-air water reservoir is located on the summit of the highest hill in the City (hence the name “Reservoir Woods”), bounded by oak forest, prairie and wetland on the west, and by pine forest to the east. In addition to more familiar birds, the Woods are home to indigo buntings, bluebirds, flycatchers, orioles and rose-breasted grosbeaks. There are hawks and owls, warblers and ducks. The park even hosts the state’s largest Butternut tree. In 2004 it was measured at 76′ tall and 236′′ in circumference (75.1′′ in diameter). The butternut tree is considered to be an endangered species of tree. It is remarkable to have an intact natural area like this so close to an urban core.
In the 20 years since the City of Roseville Parks and Recreation Natural Resource Management Final Report was released, city staff, consultants and volunteers together have removed invasive species and restored the prairie and woodlands. It is gratifying to see rue anemone and Jack-in-the-Pulpits growing where invasive European buckthorn used to be, and wild lupines bloom in response to a prescribed prairie burn.
Over the last year however, regular walkers in the Woods have seen trees taken down and others girdled and have expressed concern. Why are trees being removed? To answer this question requires an understanding of oaks.
Reservoir Woods is home to red, pin and white oaks, with bur oaks on drier upland slopes. These trees are invaluable to wildlife both for food (acorns) and shelter. As a vital link in the food chain, oaks support the largest diversity and biomass of insects (think caterpillars) that birds need to feed themselves and their young, of any tree in North America. Incompatible and excessive levels of grazing following Euromerican settlement and in the absence of regular fire as practiced by indigenous peoples, the forest became choked with shade-tolerant understory shrubs and trees, much of it is non-native buckthorn. Because oak seedlings cannot survive such dense shade, the next generation of young oaks have not been able to establish to take the place of the aging oaks. Removing invasive, nonnative shrubs and thinning select trees helps sustain the health of the remaining large oaks and improve the conditions for oak seedlings to grow and take the place of aging oaks. In areas where buckthorn is largely under control, attention has turned to other species that, while native and beneficial in limited quantities, can be invasive. Boxelder, Aspen, and sumac are some examples. These are the tree species targeted most recently. The City’s plan is to protect and continue ecological restoration work at Reservoir Woods. In time, our generation will have an opportunity to experience the vibrant plant communities our forebears once found.
About the author: Anna Newton has lived in Roseville since 2015, walks Reservoir Woods regularly with her husband and two Labrador retrievers, and has volunteered in various capacities around town. She is an avid gardener and observer of nature.
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