South Central Connecticut Regional Water Authority: Chestnut Hill Silviculture for 2120

Yes
Planning
The South Central Connecticut Regional Water Authority is working to encourage tree species that will thrive now and provide the seed source for a forest that is adapted to the climate 100-200 years into the future.

Project Area

The project area is a 608-acre compartment of the public water supply watershed of the South Central Connecticut Regional Water Authority (SCCRWA). The forest helps protect water quality for a drinking water system that supplies 400,000 people. The goal of the project (the climate change challenge) is to identify the species to encourage today that will thrive now and provide the seed source for a forest that is adapted to the climate 100-200 years from now. The forest is primarily central hardwoods transitional between oak hickory and northern hardwoods. There are also stands of white pine, transition hardwoods on the best sites, and lowland forest on the wettest sites supporting timber species. Much of the forest is more than 100 years old and many trees appear to be reaching physiological maturity. The operational goals are to protect water quality, generate income from timber harvests, protect wildlife habitat, and provide recreational opportunities, primarily in the form of a hiking trail. Objectives include keeping the forest in an aggrading state by regeneration and thinning, based on health, vigor, and density of the overstory, maintaining snags and cavity trees, and trees and shrubs with high wildlife or aesthetic value. Regeneration is subject to moderately high deer browsing and competition with invasives. Forestry here typically relies on natural regeneration, but some planting to establish tree species that are better adapted to the future climate is also under consideration.

Management Goals

a small waterfall in the forest

The major goal for the Water Authority is to protect forests in the watershed as a means of safeguarding the water supply for 400,000 people who live in the area. Forest management is used to ensure the health and productivity of the watershed’s forests, as well as to harvest timber to generate income. Forest management activities across the watershed also work to enhance wildlife habitat and provide recreational opportunities. Some specific management objectives in this project area include:

  • Maintain forest conditions with positive net growth (tree growth is exceeds losses from mortality or harvest) across a variety of sites.
  • Thin overstocked stands to provide growing space for most vigorous and valuable timber, including precommercial thinning where needed.
  • Complete a shelterwood seed cut on the most poorly-stocked 5% of forest every 10 years..
  • Retain snags (standing dead trees) and cavity trees at specific densities. Maintain the highest density of snags and cavity trees within 300 feet of water.
  • Create patch openings during regeneration harvests, and cluster these openings.
  • Provide interpretive signs during and after harvests visible from hiking trails and roads.
  • Protect and encourage vegetation with visual appeal and high wildlife value, regardless of timber value, along trails and public roads using commercial and non-commercial forestry techniques.

Climate Change Impacts

For this project, the most important anticipated climate change impacts include:
Accelerated decomposition: A longer season for decomposers will reduce forest floor organic matter and release soluble nutrients into soils. This could increase nutrient flow into reservoirs, contributing to eutrophication and diminished water quality.
Increased forest pest activity: Higher winter temperatures may favor pests such as southern pine beetle, which is expanding northward. Stressed trees will be more vulnerable to threats such as two-line chestnut borer, dogwood borer, and Armillaria.
Decreased diversity: Hemlock and sugar maple may become less vigorous and less able to reproduce, and invasive species create challenges for native plants.
Challenges to regeneration: Many anticipated stressors—including warmer temperatures, drought risk, wildfire, and invasive species—may make it more difficult for seedlings to establish and thrive.

Challenges and Opportunities

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

Challenges

Increased rates of disturbance by insects, diseases, and high winds could reduce forest productivity, adversely alter canopy cover, and force rescheduling of silviculture to conduct salvage harvests.
Invasive plant species may compete with desired species during regeneration, and higher deer density may limit growth of desirable species.
Disturbances such as insect and disease outbreaks and high winds may disrupt trees adjacent to trails and roads used for recreational activities.

Opportunities

A longer growing season could make the forest more productive, if the trees benefit more than the bugs.
There may be more snags created by pests, which could benefit some wildlife.

Adaptation Actions

The Adaptation Workbook was used to identify some potential adaptation actions that are intended to help maintain ecosystem function and protect reservoir water quality. Most of the forest is central hardwoods, which in Connecticut is expected to be tolerant of a warming climate, and much of the actions are centered on building resilience to disturbances that are anticipated in the future. Other actions, such as favoring and planting potentially future-adapted tree species in some locations are directed toward transitioning the forest to be better adapted to a warmer climate.

Area/TopicApproachTactics
Project area
1.1 Reduce impacts to soils and nutrient cycling.
Keep more woody debris on site. Restrict removal of limb and topwood during harvesting, and leave in contour-following bands (i.e., build nutrient bars)
Seed disturbed areas with native herbaceous species to sequester nutrients released from decomposition
9.6. Manage for species and genotypes with wide moisture and temperature tolerances.
Reserve the most vigorous trees on the most droughty and southerly-exposed sites to serve as seed trees
8.1. Use seeds, germplasm, and other genetic material from across a greater geographic range.
Combine planting of exotic species expected to be well-adapted, such as pitch, loblolly, and Virginia pine and sycamore with clearcutting of patches
3.3. Alter forest structure to reduce severity or extent of wind and ice damage.
5.2. Maintain and restore diversity of native species.
Develop adaptive-ness ratings for species found in project area (using information such as the Climate Change Tree Atlas) and use information to inform prescriptions for harvesting and retention

Monitoring

Several monitoring items were identified that could help inform future management. Measuring forest stocking and tree mortality during forest inventory will provide information on whether the forest is continuing to remain healthy and grow. Forest inventory data can also be used to determine whether forest management is increasing the diversity of age classes and tree species that are present, as well as favoring species that are likely to be adapted to future conditions. Seedling survival would be monitored following all plantings.

Project Photos

Click to enlarge photos

a dead tree standing in the forest
a trail in the woods
A log truck is loaded with recently cut wood in the forest.
A view from inside of a forest.

Learn More

To learn more about this project, contact Maria

Keywords

Insect pests, Invasive species, Upland hardwoods, Assisted migration, Water resources

Last Updated

Monday, May 7, 2018