Saint Paul’s Gravel Bed Nursery Project: Maximizing the Benefits of Urban Trees

Created: 11/20/2016 - Updated: 3/02/2020


Mississippi Park Connection and the National Park Service is coordinating volunteers to work on a gravel bed tree nursery project at the Science Museum of Minnesota’s Saint Paul campus. The gravel bed nursery will feature trees that are adapted to climate change conditions, such as Kentucky coffeetree, and will eventually be planted in Saint Paul along the Mississippi River. Volunteers from the Minnesota GreenCorps program, the 2017 National Adaptation Forum, and the general public will perform the work. 


With the increased loss of ash trees in Saint Paul and surrounding communities due to the invasive emerald ash borer beetle and a maturing urban forest, reforestation efforts and accompanying care required during the establishment period (i.e. watering and structural pruning) are essential. The City of Saint Paul is removing and replacing ash trees throughout the city as part of its Emerald Ash Borer Management Plan and is expanding the use of gravel bed nurseries as an additional source of trees. Gravel beds provide a source of high-quality trees at a reduced cost, allowing for increased tree planting within existing budgets. A gravel bed is an irrigated bed or pile of gravel to place and safely hold bare-root or washed containerized nursery stock for up to 3-6 months. Doing this dramatically increases fibrous root volume, decreasing transplant shock and increasing survivability of the plant. Since bare-root nursery stock is typically only available during certain times of year, this also allows for staged plantings throughout the year.

The Science Museum of Minnesota, Mississippi Park Connection, the National Park Service, and Saint Paul Parks and Recreation received funding from the Minnesota Pollution Control Agency’s Environmental Assistance grant program to work in partnership on a gravel bed tree nursery project. This project is intended to help the City of Saint Paul increase carbon storage, create a more climatically-suitable urban forest in the city, and help reduce the urban heat island effect, as well as energy demand for heating and cooling services.


The project’s goals are to:

  • Install and demonstrate a successful, temporary gravel bed nursery on Kellogg Blvd. in Saint Paul in front of the Science Museum, using trees that are likely to survive in a changing climate, such as Kentucky coffeetree, chinkapin oak, disease-resistant elm, buckeye, tulip poplar, American sycamore, black oak, and black maple.
  • Provide educational and interpretive signage and information about the gravel bed nursery to the public and provide tours of the site to interested parties. Signage will be installed to describe the project and make it an exhibit of the Science Museum of Minnesota. National Park Service rangers and volunteers who staff the Mississippi River Visitor Center in the lobby of the Science Museum will receive training on how to talk to the public about the gravel bed project, and could provide interpretation upon request.
  • Host volunteer events in partnership with Minnesota GreenCorps and the 2017 National Adaptation Forum. The Forum event will use trees from the gravel bed nursery and recently purchased trees. The advantages of the nursery will be demonstrated by showing the difference in the root-balls of trees grown in the nursery and others not grown in the nursery. Information about gravel bed nurseries will be made available. After the Forum, both the purchased trees and the gravel bed nursery trees will be planted along Shepard Rd. near Upper Landing Park in Saint Paul, within the Mississippi National River and Recreation Area. The trees will replace ash trees that will likely soon be lost to emerald ash borer activity.
  • Reach a broad audience and provide education and interpretation on urban forestry and climate change in a highly visible location in front of the Science Museum. This project serves as a demonstration project and introduces the public to the idea of gravel beds. 

Outcomes and Conclusions

The projected cost of the project is $42,102 with $21,035 grant funded and $21,067 in matching funds. However, it should be noted that this particular project is higher in expense than most gravel beds due to the location. We feel that the highly-visible location, which makes this project such a great demonstration, is worth the additional cost. At the end of fall 2017, the temporary gravel bed nursery will be removed unless there is sufficient interest and funding to continue the gravel bed nursery program.


Submitted by CAKE user and reviewed by Content Editor


Hammes, M. 2016. Saint Paul’s Gravel Bed Nursery Project: Maximizing the Benefits of Urban Trees. Ed. Rachel M. Gregg [Case study on a project of the Mississippi Park Connection, Science Museum of Minnesota, City of Saint Paul, and the Mississippi National River and Recreation Area] Retrieved from CAKE: (Last updated November 2016)

Project Contact(s)

Position: Environmental Stewardship & Volunteer Manager


Scale of Project
Community / Local
Sector Addressed
Target Climate Changes and Impacts
Air temperature
Climate Type
Type of Adaptation Action/Strategy
Natural Resource Management / Conservation
Reduce local climate or related change
Capacity Building
Increase / Improve public awareness, education, and outreach efforts
Create stakeholder engagement processes to develop and implement adaptation strategies
Habitat/Biome Type
Taxonomic Focus
Sociopolitical Setting
Effort Stage
In progress