• Start-up
  • Planning
  • Action
  • Evaluation
The Adaptive Silviculture for Climate Change (ASCC) Network is a collaborative effort to establish a series of experimental silvicultural trials across different forest ecosystem types. We are currently implementing an affiliate trial within the Mississippi National River and Recreation Area, a national park along the Mississippi River in the Twin Cities Metro Area of Minnesota.
Group of ASCC project members in a a vine-covered gap
National park service
working in the workshop
Forest

Project Area

Floodplain forest at Crosby Farm Park
The size of Crosby Farm Regional Park, its diversity of life, many recreational opportunities, tranquil settings, and easy access makes this a popular park to escape the bustle of a frenzied city life. Mostly floodplain forest, Crosby Farm is a place to wander its many paths and bike trails to enjoy the river and forests and is a destination for birders, especially during spring and fall migration.
Some key facts:
- 549 acres
- A 10 minute drive from downtown St. Paul
- Largest natural park in the city
- 530,000 visitors annually
Learn more here: https://www.stpaul.gov/facilities/crosby-farm-regional-park

Management Goals

Large room with scientists and managers at a workshop

A team of over thirty floodplain forestry specialists from the region joined researchers and managers for a two-day workshop in March 2019 to develop the study design for the ASCC project site.  The team developed a set of Desired Future Condition statements, Objectives, and Tactics for each major climate adaptation trajectory (resistance, resilience, transition). These three treatments are summarized briefly below:

 

 

Resistance:

  • Maintain closed canopy condition 
  • Maintain the current species composition in the tree canopy and regeneration layer of the floodplain forest ash-elm species 
  • Promote or enhance native regeneration 
  • Manage to decrease invasive species cover (trees and herbaceous)
  • Maintain large diameter trees while creating a range of diameter classes for wildlife habitat 
  • Maintain vigor of existing desirable trees
  • Maintain recreation value and opportunities for multiple use of the area
  • Strive for an educated and engaged public 

Resilience:

  • Promote a broad suite of future climate-adapted species (flood-tolerant and drought-tolerant) native to the Mississippi River Basin 
  • Promote less common native species
  • Promote trees with vigor and seed potential
  • Low herbivory
  • Low abundance of invasive species 
  • Provide wildlife trees with big crowns and cavity trees or snags for nesting wildlife species 
  • Maintain recreation value and opportunities for multiple use of the area
  • Strive for an educated and engaged public 

Transition:

  • Promote a broad suite of future climate-adapted species (flood-tolerant and drought-tolerant) from seed zones farther south along the Mississippi
  • Create a diversity of canopy cover conditions over space and time that is heterogeneous for regeneration
  • Promote heterogeneous age classes and canopy structure
  • Maintain recreation value and opportunities for multiple use of the area
  • Strive for an educated and engaged public 

Climate Change Impacts

For this project, the most important anticipated climate change impacts include:
Warmer temps, especially night-time in both summer and winter
Wetter – more heavy rain events, flooding
More drought stress in summer
Shift of hardiness zones to 5 or 6 (similar climate to Omaha, NE)
Extreme events, including polar vortex impacts – extreme low temps in winter
Invasive species considerations

Challenges and Opportunities

Climate change will present challenges and opportunities for accomplishing the management objectives of this project, including:

Challenges

Tree species currently found in the park are expected to see reduced habitat suitability under climate change, including northern white cedar, black willow, silver maple, cottonwood, and boxelder.
Ash species are declining due to emerald ash borer and are expected to largely disappear from the forest canopy.

Opportunities

Some tree species are expected to have increased habitat suitability under climate change, including bur oak, swamp white oak, hackberry, American elm, and red mulberry.
Habitat suitability for honeylocust, sycamore, and swamp white oak is also projected to increase (currently found in similar floodplain forests in southern Minnesota and Iowa).

Adaptation Actions

The ASCC project was designed to explicitly test three different adaptation options: resistance, resilience, and transition. A detailed silvicultural prescription was designed for each adaptation option, which was replicated several times across the study site. Detailed silvicultural prescriptions can be found in the Adaptation Workbook. The study site also includes several no-action "control" stands for comparison. Some of the adaptation tactics employed in this project include:

Area/Topic
Approach
Tactics
Resistance
2.2. Prevent the introduction and establishment of invasive plant species and remove existing invasive species.
2.3. Manage herbivory to promote regeneration of desired species.
5.2. Maintain and restore diversity of native species.
5.3. Retain biological legacies.
Site prep for natural regeneration and planting
Scout, treat, and remove invasive plant populations
Create gaps for regeneration using the following prioritization:
1. Utilize natural gaps (dying ash pockets/cottonwood gaps) for regeneration
2. Remove “hazard” trees from trails (hazard removal is the priority for all treatments including control/no action)
3. Create additional gaps for regeneration of desired species if natural gaps and hazard tree removal options do not provide enough opportunities for desired species regeneration
Maintain large diameter trees, particularly silver maple and cottonwood, as well as large-diameter standing dead for wildlife habitat and eagle nesting
Consider treating selected large ash
Plant under-represented species that currently grow on site: silver maple, hackberry, cottonwood, and Dutch-elm resistant American elm seedlings to help maintain the floodplain forest ash-elm cover type
Protect all regeneration from herbivory using deer exclosures around plantings
Allow natural flood deposition and use as microsites for planting future-adapted species
Use volunteers and increase visitation, education, and use of Crosby Farm Regional Park as a teaching forest
Resilience
2.2. Prevent the introduction and establishment of invasive plant species and remove existing invasive species.
2.3. Manage herbivory to promote regeneration of desired species.
8.1. Use seeds, germplasm, and other genetic material from across a greater geographic range.
9.1. Favor or restore native species that are expected to be adapted to future conditions.
Site prep for natural regeneration and planting
Scout, treat, and remove invasive plant populations
Create gaps for regeneration around high-value, large-diameter seed trees using the following prioritization:
1. Utilize natural gaps (dying ash pockets/cottonwood gaps) for regeneration
2. Remove “hazard” trees from trails (hazard removal is the priority for all treatments incl. control/no action)
3. Create additional gaps for regeneration of desired species if natural gaps and hazard tree removal options do not provide enough opportunities for desired species regeneration
Create skips in areas where the canopy cover target is important
Plant species that are currently found onsite using a southern seed zone location (silver maple, hackberry, cottonwood, Dutch elm-resistant American elm, bur oak, black willow)
Plant species that may currently be offsite but within geographic range of the Mississippi River Basin (swamp white oak, river birch, peachleaf willow, red mulberry, Kentucky coffee tree)
Plant species on appropriate microsites, especially with respect to potential changes in flooding regime and hydrological changes with climate change
Protect all regeneration from herbivory using deer exclosures around plantings
Allow natural flood deposition and use as microsites for planting future-adapted species
Use volunteers and increase visitation, education, and use of Crosby Farm Regional Park as a teaching forest
Transition
2.2. Prevent the introduction and establishment of invasive plant species and remove existing invasive species.
2.3. Manage herbivory to promote regeneration of desired species.
9.2. Establish or encourage new mixes of native species.
9.7. Introduce species that are expected to be adapted to future conditions.
Site prep for natural regeneration and planting
Create gaps that are ideally 1 acre to 1.5 acre to accommodate selected species, avoiding river edges while creating a variety of microsites for species
Details for gaps: expand gaps with feathered edges; girdle trees on edges; create microsites for planting
Plant containerized and bare-root stock of sycamore, honey locust, southern pin oak, swamp white oak, river birch in the gaps; and winged elm, red maple, red mulberry, northern catalpa along the edges
Treat invasives where they are impacting regeneration
Monitor for stressors and survival and adjust as needed (adaptive management)
Protect all regeneration from herbivory (deer and beaver) using deer exclosures around plantings, but also consider alternative options of fencing, repellent, and seedling tubes
Retain large-diameter standing dead for wildlife habitat
Allow natural flood deposition and use as microsites for planting future-adapted species
Use volunteers and increase visitation, education, and use of Crosby Farm Regional Park as a teaching forest

Monitoring

Baseline data was collected in fall 2019 and plots are being monitored throughout the 20-year project, for example:
Overstory measurements (overstory are trees greater than 5 in. dbh) (status, species, height, health, etc.)
Seedlings and Saplings (1 to 4.9 inches dbh) of live trees (species, size class, forest health concerns)
Herbaceous layer
Down dead wood
Soils

Project Documents

Project Videos

Next Steps

Trees were planted in spring 2020 and survival is being monitored. Learn more about this project on the Adaptive Silviculture for Climate Change website: https://www.adaptivesilviculture.org/project-site/mississippi-national-river-and-recreation-area

Learn More

Keywords

Assisted migration
Flooding
Genetic diversity
Insect pests
Lowland/ bottomland hardwoods
Planting
Research

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