Project Area
The Green Hills Preserve is 5,567 acres managed by The Nature Conservancy in east-central New Hampshire. The preserve includes mixed hardwood forests, northern hardwood forest, exposed rocky ridge communities dominated by red pine and pitch pine, deer wintering areas, and a variety of headwater streams and wetlands. Within the 1,328-acre project area, the dominant trees include northern red oak, American beech, eastern hemlock, and lesser amounts of red pine, pitch pine, white pine, and bigtooth aspen. The project area has a southern aspect that may be more susceptible to drier conditions. A spongy moth outbreak that defoliated ~40,000 acres in Carroll County in 2021 and 2022 impacted the project area and there has been significant mortality in the overstory northern red oak as a result. The outbreak also caused significant mortality of eastern hemlock in both the canopy and the advance regeneration, exacerbating the lack of tree species diversity.
Management Goals
Promote diverse regeneration to ensure diverse forested habitats, mitigate the negative impacts of forest pests and pathogens, and increase the potential for carbon sequestration and storage.
- Plant tree species expected to be adapted to future climate to increase diversity, including forest assisted migration species that are not currently established at the site. Focus on trees that have wildlife benefits (mast producing) and may help increase site-level carbon sequestration (white oak, chestnut oak, etc.).
- Where possible, protect regeneration from herbivory.
Enhance the compositional and structural diversity of forested habitats to build climate resilience and provide habitat for State Wildlife Action Plan (SWAP) species.
- Implement silvicultural approaches to recruit shade intolerant tree species and develop new age classes, including patch cuts that can provide habitat for early successional species.
Manage for old forest characteristics within a portion of the site to develop biological legacies, promote resilience, and provide old forest habitat for SWAP species.
- Implement silvicultural approaches to promote the growth and development of large, healthy trees.
- Increase deadwood pools by protecting legacy trees and felling and leaving large, low value trees for down woody debris.
Improve the ability of the site to withstand and recover from large precipitation and major flooding events.
- Add deadwood to streams to improve habitat for fish and other aquatic organisms and promote resilience to large flooding events.
- Designate reserve areas around riparian zones, wetlands, and seeps.
Grow high quality sawlogs that can be used to generate sustainable and durable forest products and support the local economy.
- Implement silvicultural approaches to promote the growth and development of large, healthy trees.
Demonstrate best practices and techniques for climate adaptive management across the spectrum of Resistance, Resilience, and Transition (R-R-T) options.
Challenges and Opportunities
Climate change will present challenges and opportunities for accomplishing the management objectives of this project, including:
Challenges
Climate driven impacts, seasonal extremes (drought, flooding, heat), and forest pests and pathogens will make it more difficult to maintain and increase tree species diversity.
Past management has favored beech regeneration leaving a less diverse forest. Climate stress may reduce opportunities to recruit and increase diversity.
Extreme storms and high winds may challenge actions intended to enhance forest structure (such as retention areas).
Impacts from forest pests and pathogens challenge retention of old forest pockets and canopy trees.
The southerly aspect of the site is more susceptible to seasonal drought that may affect regeneration resulting in more beech tree suckering and young growth.
Increased risk of drought may reduce the survivorship of any enrichment plantings.
Herbivory (deer, moose) threatens seedling survival from enrichment planting and natural regeneration.
Opportunities
More frequent extreme disturbance events could increase diversity of age classes, and forest structure over time (downed wood, snags, tip ups).
Drier conditions may favor oak and enable it to outcompete American beech over time.
A longer growing season presents more opportunities to manage for oak regeneration during snow-free periods.
Maintaining the unique red pine and pitch pine communities (dry pine oak forests) within the site may be easier under warmer and drier climate conditions.
Wildlife species on the site adapted to warmer, drier conditions may cope with changing conditions better than others.
Impact from pests and pathogens may accelerate the development of deadwood pools.
Adaptation Actions
Project participants used the Adaptation Workbook to develop several adaptation actions for this project.
A portion of this project is part of an experimental design to test the efficacy of different management approaches to advance the goals and objectives. A combination of patch cuts, crop tree release, and late seral stage treatments representing Resistance, Resilience, and Transition options have been implemented with replicates across the site. No-action “control” stands were also designated for comparison. The configuration of these management areas can be seen in the Experimental Area Map. The following table shows all the adaptation tactics currently being used at the site:
Area/Topic
Approach
Tactics
Riparian areas, Resistance & Resilience
1.3: Maintain and restore stream channel form and function
3.1: Maintain or restore forest and riparian areas
3.1: Maintain or restore forest and riparian areas
Establish 100’ riparian buffers around headwater streams and opportunistically enhance old forest characteristics.
Add deadwood to streams to enhance instream habitat for fish and other aquatic species, and slow water during large flooding events.
Resistance & Resilience
1.4. Reduce competition for moisture, nutrients, and light.
2.1. Maintain or improve the ability of forests to resist pests and pathogens.
2.1. Maintain or improve the ability of forests to resist pests and pathogens.
In areas with more species diversity in the advance regeneration, apply crop-tree release to 50 crop trees per acre by releasing 2 sides of the crop tree crowns. When possible, crop trees should focus on better quality northern red oaks.
Within hemlock-dominated stands, create single tree (50 ft. diameter; 0.05 acres) and small group selection (100 ft. diameter; 0.2 acres) openings in 10-20% of the stand to increase air flow and foliar cover on hemlock to help mitigate damage from HWA.
Resilience
In areas where the advance regeneration is dominated by American beech, implement patch clearcuts up to 5-acres in size to develop new age-classes.
Within hemlock-dominated stands, create single tree and small group selection openings in 10-20% of the stand with a focus on releasing existing pockets of eastern hemlock and red spruce advance regeneration.
In areas where the advance regeneration is dominated by American beech, implement patch clearcuts up to 5-acres in size to recruit diverse regeneration.
Apply mid-story removal in half of each area treated with crop tree release using a combination of a beech-frill roundup technique and mechanical removal of the understory to encourage the development of northern red oak and eastern white pine.
Implement TSI in hemlock-dominated stands between regeneration openings to accelerate the growth of eastern hemlock, red spruce, eastern white pine, and northern red oak canopy trees where present.
Resilience & Transition
Protect and retain legacy trees that can contribute to future deadwood pools.
Designate and build reserves around riparian zones, wetlands, and forest seeps.
To develop deadwood pools, where possible fell and leave 5-7 whole trees (large, low value) per acre across the site within the areas where management is occurring.
Transition
2.3. Manage herbivory to promote regeneration of desired species.
9.7. Introduce species that are expected to be adapted to future conditions.
9.7. Introduce species that are expected to be adapted to future conditions.
Plant the central one-acre portion of each patch clearcut with species expected to be adapted to future climate and provide browse protection for half the planted stems. (See planted species list under Project Documents.)
Underplant in crop tree release areas at low density with future adapted tree species.
Supplement the softwood regeneration in hemlock dominated stands with red spruce and eastern hemlock plantings, including hemlock wooly adelgid-resistant seedlings if available.
Monitoring
Project participants are monitoring several items that could help inform future management, including:
Natural regeneration in silvicultural treatment areas
Residual tree survival and growth
Planted seedling survival and growth
Development of carbon pools through living and downed wood material
Songbird and wildlife community responses
Presence and distribution of forest pests and pathogens, invasive plant species, and other spatially explicit stressors
Changes in forest canopy structure using high-resolution LiDAR
Project Documents
Green Hills planted species list_0.pdf
(100.23 KB)
GreenHills_TreatmentAreas.pdf
(3.58 MB)
Green Hills Handout July 2025.pdf
(2.36 MB)
2025_Green_Hills_Wildlife_Montioring_Handout.pdf
(229.06 KB)