• Start-up
  • Planning
  • Action
  • Evaluation

Restoring and Connecting Forests in a Changing Climate

The Nature Conservancy in Ohio is thinking about how to reforest and restore floodplain and upland forests in a changing climate.

Project Area

Map of landscape showing the project boundary. Photos by Andrew Bishop.
This project is set within Cuyahoga Valley National Park in Northeast Ohio. The Nature Conservancy is working with the National Park Service to restore landscapes and watershed health of the Cuyahoga River within this 33,000-acre valley park. The park is unique and treasured because it protects a large area with high topographic diversity and species richness. This project focuses on reforesting two former agricultural sites and improving diversity and resilience of adjacent forest stands. The Cull site is along the Cuyahoga River, and the Kurowski site is at the headwaters of two of the river’s high-quality tributaries. Three forest ecosystems make up the project area:

1. Large stream floodplain and riparian forest occurs as a complex of wetland and upland vegetation associated with the Cuyahoga River where topography and alluvial processes have resulted in a well-developed floodplain. Common species include silver maple, eastern cottonwood, pin oak, red maple, black willow, sycamore, sweetgum, green ash, American hornbeam, black walnut, American elm, boxelder, and red oak.

2. Dry/mesic oak forest includes two matrix-forming oak-dominated systems that are only weakly differentiated and occupies more area than any other in the Central Appalachians. Common species include white oak, black oak, northern red oak, scarlet oak, red maple, pignut hickory, mockernut hickory, shagbark hickory, sugar maple, American beech, black gum, and tulip tree.

3. North-central interior beech-maple forest primarily occurs in the glaciated portion of Ohio, where varying microtopography and moisture regimes create mixed communities of upland and lowland species. Common species include sugar maple, American beech, northern red oak, American basswood, eastern hemlock, black cherry, tulip tree, red maple, white ash, and eastern hophornbeam.

Management Goals

Picture of forest stand

Broad management goals include: 

  • Convert 85 acres of degraded field habitats (with many invasive species) to mature forest with diverse species and structure;
  • Reconnect and enlarge core forest blocks;
  • Selectively thin and underplant 10 acres of young, even-aged forest;
  • Minimize invasive species to reduce negative effects on disturbance regimes and ecological processes (e.g., forest regeneration, clean water, and soil health). 
Map showing boundary of the Cull site
Degraded field habitat at the Kurowski site. Photo by Andrew Bishop.

 

Climate Change Impacts

The project area will likely be affected by significant climate changes over the next century:
Greater drought stress will weaken mature trees and increase mortality of seedlings.
The Kurowski site will likely experience greater erosion of headwater streams, while the Cull site may experience flooding from the Cuyahoga River.
Soil moisture patterns may change, with possible drought stress later in the growing season.
Both sites currently have invasive species and these are expected to increase or become more damaging.
The dominant species in the study area are projected to decline under climate change. The Cull site will require a new species mix to retain resilience.

Challenges and Opportunities

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

Challenges

Increased drought stress will increase mortality of tree seedlings and threaten the establishment of current dominant tree species in this community.
American Sycamore, eastern cottonwood, swamp white oak (dominant species in this habitat) are predicted to decline.
The restoration site is in the floodplain of the Cuyahoga River and more extreme flood events will threaten establishment of seedlings.
Invasive species will thrive with decreased flood return interval, and possibly out-compete native regeneration.

Opportunities

Dry/mesic species (eg. white oak, northern red oak, several hickory species) are predicted to not change or increase in abundance and importance under climate change models.
Increased temperature and drought will make fuels more flammable and increase the likelihood of natural fires that can be tools to help manage invasive species.
Some invasive species (eg. garlic mustard and Japanese stiltgrass) are susceptible to drought and some native species may have a leg up on these species in a more droughty climate.
Increase tree mortality from forest pests will drive an influx of large woody debris on the forest floor that can reduce erosive energy of surface flow.

Adaptation Actions

Project participants used the Adaptation Workbook to develop several adaptation actions for this project, including:

Area/Topic
Approach
Tactics
Large stream floodplain and riparian forest
Plant a diverse mix of species that is adapted to future climate, such as planting species with a wide geographic and climatic range, genotypes from further south, and southern species.
Perform targeted control priority invasive species particularly in and around sensitive habitat such as riparian areas, wetlands and steep slopes.
Evaluate and release biocontrol agents for most disruptive invasive species, such as Japanese knotweed, garlic mustard.
Dry/mesic oak forest and North-central interior beech-maple forest
Plant a diverse mix of species that is adapted to future climate, such as planting species with a wide geographic and climatic range, genotypes from further south, and southern species.
Use prescribed fire to control invasive species and maintain an open forest understory that is conducive to oak-hickory regeneration.
Perform targeted control of priority invasive species particularly in and around sensitive habitat such as riparian areas, wetlands and steep slopes.
Evaluate and release biocontrol agents for most disruptive invasive species, such as Japanese knotweed, garlic mustard.
Use selective thinning to promote species predicted to do well while thinning out species (i.e., American Beech, red maple) that are predicted to do poorly.

Monitoring

Project participants identified several monitoring items that could help inform future management, including:
A goal of 70% seedling survival of all desired individuals;
Between 65% and 90% stocking ratio. If below 65% this triggers replanting or protecting seedlings, if over 90% this triggers selective thinning of stand;
Structural diversity based on calculation of shannon index for species, height class, and combined calculations using seedling diversity and heights, sapling diversity and height, overstory forest inventory (species, count, basal area), canopy cover.
Less than 20% cover of invasive species in all habitat types;
Soil compaction and infiltration rate at dry/mesic oak site

Next Steps

TNC has received funding to reforest the Cull Field site. The grant agreement has been signed and the project is slated to be completed by Jun 2024.

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