• Start-up
  • Planning
  • Action
  • Evaluation
The Driftless Area is participating in a study called Adaptive Silviculture for Climate Change (ASCC) Network. This project 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 Driftless Area to test different silvicultural approaches to climate change and forest health adaptation that will also serve as useful examples across the U.S. and Canada.

Project Area

View of the Driftless Area ASCC site. Photo Credit: Courtney Peterson, Colorado State University.
The Driftless Area ASCC project sites are located in northeastern Iowa, southeastern Minnesota, and southwestern Wisconsin. Each site has silt loam soils and mature dry-mesic forests dominated by northern red and white oak.

Management Goals

Research partners working together to develop Driftless Area ASCC Affiliate Site. Photo Credit: Courtney Peterson, Colorado State University.

A team of natural resource specialists, managers, and scientists representing the Driftless Area came together for a virtual three-day workshop in December of 2021 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 climate adaptation option (resistance, resilience, transition). These three treatments are summarized briefly below:

 

Resistance:

  • Maintain northern red oak and white oak > 50% BA
  • Stocking maintained around 70%
  • Increase the size and quality of overstory trees
  • Maintain sparse and native midstory, allowing for advanced regeneration of oak and hickory species
  • Reduce the prevalence of invasive species

Resilience:

  • Multi-cohort stand with greater structural complexity, larger trees, and maintained or increased quality
  • Favor native mast-producers that are drought, fire, frost, disease, and wind tolerant
  • Increase genetic diversity of tree community
  • Maintain spare and native midstory, allowing for advanced regeneration of oak and hickory species
  • Provide hard and soft mast for wildlife
  • Reduce prevalence of invasive species

Transition:

  • Two-cohort stand with greater structural complexity
  • Encourage native and novel future-adapted species that are drought tolerant, disease resistant, and/or adapted to fire
  • Reduce prevalence of invasive species
  • Increase species and functional diversity of tree community
  • Provide hard mast for wildlife
  • Encourage future-adapted species with potential economic value

Climate Change Impacts

Key climate change impacts that the project team considered for the Driftless Area included:
Increased average annual temperatures, particularly in winter months
More frequent heavy precipitation events
Increased drought stress
Increased threat of forest pest, disease, and invasive species

Challenges and Opportunities

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

Challenges

Forest in this region are susceptible to invasive species that may benefit from longer growing seasons, including buckthorn, bush honeysuckle, garlic mustard, and multi-flora rose.
Limited fire is likely to hasten the conversion to mesic species, restricting oak regeneration.
Uncertainty around the ability to apply prescribed fire as a management tool.
Greater risk of water stress for regeneration.
Despite warmer average temperatures, cold snaps may limit otherwise future-adapted species.
Projected climate conditions may limit operability.

Opportunities

Many native tree species are expected to maintain or gain suitable habitat under climate change, including northern red oak, white oak, shagbark hickory, bitternut hickory, and sugar maple.
Sites that have been managed with fire may be more adaptable with more favorable conditions to perpetuate oak.

Adaptation Actions

The Driftless Area 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. Some of the adaptation tactics employed in this project include:

Area/Topic
Approach
Tactics
Resilience
Invasive shrub treatment
Midstory removal
Site preparation including prescribed fire if conditions allow
Underplant intermediate, shade-tolerant, fire-adapted native species
Continuous cover irregular shelterwood: first and subsequent establishment cuttings will create three 0.75-acre opening and three 0.75-acre patches 40-50% cover
Free thinning matrix to ~70% stocking
Retain some dominants as seed trees, plant additional seedlings (chinkapin oak, white oak, northern red oak, black walnut, bur oak, shagbark hickory, black oak, black cherry)
Transition
Invasive shrub treatment
Midstory removal
Site preparation including prescribed fire if conditions allow
Underplant with future-adapted species
Clearcutting with reserves (variable retention harvest): retain 20% overstory, some aggregated (0.25-0.5 acres in area) and some dispersed
Increase future-adapted species, including native and new, future-adapted species (white oak, northern red oak, black walnut, bur oak, shagbark hickory, mockernut hickory, pignut hickory, Shumard oak, post oak, tulip poplar, shortleaf pine)

Monitoring

Monitoring is an essential component of the ASCC study. Research partners from several institutions are working together to investigate the effectiveness of different silvicultural treatments aimed at creating adaptive ecosystems. Some of the monitoring items include:
Regeneration of planted seedlings
Residual tree survival and growth
Microclimate conditions
Wildlife response to treatments
Carbon sequestration potential

Next Steps

The Driftless Area ASCC projects sites will be tended and monitored into the future. Each of the adaptation treatments will be implemented across all sites in Iowa, Minnesota, and Wisconsin. Future data collection will focus on tree regeneration, forest growth, and forest health. Pre-treatment sampling is planned to take place in the summer of 2022.

Keywords

Fire and fuels
Forest types
Invasive species
Management plan
Planting
Research

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