Managing Urban Forests for Climate Change

Forest Service U.S. DEPARTMENT OF AGRICULTURE ISSUE 2 ConnectingThe forested communities Cross-Pollinator & delivering science for the trees outside your door Planting for the Future: Managing Urban Forests for Climate Change Applied research by the Northern Research Station and partners will help urban natural areas in Saint Paul and along the Mississippi River adapt to a changing climate. The project also has implications for floodplains elsewhere. Photo from www.goodfreephotos.com. Life and Research on Today, scientists along the Mississippi River SUMMARY are evaluating regional silvicultural strategies the Mississippi while employing an innovative approach Scientists and managers are working together through an effort called When Mark Twain’s book, “Life on the to adapting forested areas to anticipated Adaptive Silviculture for Climate Change Mississippi”, was published in 1883, change. Specifically,scientists and volunteers are creating dozens of wooded trial plots in (ASCC). This framework, primarily conditions along the Mississippi River were implemented in rural areas, is now being an urban park in Saint Paul, MN, to help changing at breakneck speed. The country applied to an area along the Mississippi manage for healthy forest characteristics was in the midst of industrialization and River National Recreation Area in the river-based transportation and shipping under a changing climate. While this project Minneapolis-Saint Paul metropolitan were rapidly being replaced by a growing represents adaptation in an urban context, area. The project involves test plots for railroad system. But while Twain’s many of the challenges are not unique to alternative climate change strategies memoirs looked back at a simpler time, urbanized areas. Wildland floodplains will in an urban floodplain forest and is the book also represented a milestone in also experience similar stresses and cross- designed to provide a degree of real- innovation: “Life on the Mississippi” was boundary collaboration will become more time feedback to managers to ensure that the forests along the river continue the first novel ever to be submitted in typed important than ever. Projects such as this to provide important services as the form to a book publisher. may have benefits for our understanding of floodplain ecosystems across gradients. climate changes. 1 important in this ecosystem after the loss of American elm trees due to Dutch elm disease. Yet when emerald ash borer wipes out green ash, there’s not going to be a lot of diversity left. There are other species that could replace ash there, but we’ll have to plant them because those other species don’t grow there yet and they aren’t likely to get there naturally any time soon. For example, there are likely replacement tree options farther south on the river, but the flow of the river is in the other direction.” These potential transplants include sycamore, southern red oak, pecan, yellow-poplar, and swamp white oak, found in similar floodplain forests in southern Minnesota and Iowa. If nothing is done, Brandt says, “The forested areas along the river could become non- forested and dominated by invasive plants. The Mississippi National River and Recreation Area protects parts of a 72-mile river corridor that includes natural areas We’re seeing that already in some places.” such as Crosby Farm Regional Park. Photo by Gordon Dietzman, U.S. National Park Service. As a result, Brandt and others are trying different approaches and mixes of trees Climate Challenges in drought stress. More specifically, in just to see what plant and tree configurations the last 15 years, the Mississippi River work best in today’s more variable and Urban Minnesota Valley has sustained successive 100-, 200-, warming climate. “We’re also leaving some The plots are located in Crosby Farm and 500-year rainfall events. Changing space to plant ash trees that are resistant to Regional Park, a 736-acre natural area environmental conditions are leading emerald ash borer, but that may be years and former farm with riverside access, a to a loss of tree canopy that is not being out,” Brandt says, as research in that area lake, marshes, fishing areas, a marina, and replaced through natural regeneration. continues. They are also planting Dutch elm paved trails that run along shady, wooded Several tree species currently found in the disease-resistant elm stock. “bottomlands”—low-lying land next to park are expected to suffer reduced habitat the river. Located in a floodplain forest suitability under climate change. These ecosystem dominated by green ash and species include northern white-cedar, black other flood-tolerant trees, Crosby Farm willow, cottonwood, and boxelder. Park is part of the Mississippi National River and Recreation Area, the only Looking South for national park dedicated exclusively to the Solutions Mississippi River. The park stretches along 72 miles of the river, through parts of five “We’re trying to adapt our floodplains to counties in the Minneapolis-Saint Paul climate change conditions by restoring a Emerald ash borer insects are expected to cause the loss metropolitan area. forested community that may be able to better withstand future changes,” according of half a million trees in the Mississippi National River and Recreation Area alone. Photo by Judy Gallagher, The park has natural, historical, to Leslie Brandt, a climate change specialist flickr.com, creativecommons.org/licenses/by/2.0. recreational, cultural, scenic, scientific, with the Northern Institute of Applied and economic resources—and it also faces Climate Science and the Northern Research several significant challenges, including Station (NRS) in Saint Paul. One of the Applying the Research emerald ash borer. Experts estimate that main researchers on the project, Brandt “Since Crosby Farm Park is in an urban in the next decade, as the invasive insect explains, “Green ash is a dominant, flood- area, our first challenge is space,” Brandt spreads throughout the area, the riverside tolerant species. It became even more explains, adding, “In rural areas, adaptive forest that runs through the Twin Cities silvicultural research would be done in metropolitan area may lose 40 percent of 25-acre test areas set up over hundreds of its canopy. The park alone is expected to “Visitors will be able to see acres. That’s not feasible in fragmented, lose half a million ash trees. first-hand what’s being smaller areas.” But the urban setting is The park also faces a host of climate- done to plan for the future important, as natural areas in urban and related impacts, many of which threaten health of the area.” rural areas alike will benefit from this kind the health of natural areas. These impacts of research. “We rely on the vegetation include higher average temperatures, –Leslie Brandt, Northern along the river to help clean the water increased precipitation, more extreme Research Station and control the hydrology,” Brandt says, flooding events, and increased summer adding, “It’s also a recreation space for 2 “People with years of land and forestry management experience are asking, ‘What do we plant?’ We won’t always have the answer but we may be able to provide suggestions.” –Mary Hammes, Mississippi Park Connection 80 percent of their work is habitat restoration.” Other collaborators include the University of Minnesota, Colorado State University, and the City of Saint Paul’s Department of Parks and Recreation. Funding for the project comes from many Crosby Farm Regional Park is the site of 25 research plots to evaluate different management approaches for sources: dozens of local partners; the future climate-adjusted riverside natural areas. Image by National Park Service, Mississippi National River and Wildlife Conservation Society through its Recreation Area. Climate Adaptation Fund via a grant by the Doris Duke Charitable Foundation; and generous donations from Mississippi Park Community Engagement Connection’s members. and Partnerships Hammes believes this work will serve as people who live in or visit the surrounding Several partnering organizations are an important example for other floodplain area. There’s hiking, biking, a beach area, involved in the Crosby Farm Park effort, forests and urban natural areas across the and river access, and it’s a cool summer including Mississippi Park Connection, nation. She explains, “People with years of location because of the trees. That’s the nonprofit organization that supports land and forestry management experience something that people are worried about the national park. According to Mary are asking, ‘What do we plant to replace losing.” Hammes, the Mississippi Park Connection’s the trees that are dying?’ We won’t always environmental stewardship and volunteer have the answer, but we may be able to Spurred in part by this concern, this 20-year manager, “Park Connection seeks to provide suggestions. It’s important to study initiative received funding in fall support the park and to connect the keep a regional focus so we can share this 2018 and a planning workshop was held the surrounding community to the river. We information all along the river.” following spring. Baseline data were collected have a pretty big volunteer program— in summer 2019 and project implementation The work also provides an opportunity to more than 5,000 people annually—and began in fall 2019, with planting in May and engage the public in forest management June 2020, following Covid-19 through citizen/community guidelines. “Record flooding

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