Northern hardwood forests are already being affected by climate change, which creates challenges for sustaining ecological, economic, and cultural benefits that these forests provide. There are many adaptation management actions that can address these key challenges based on site-specific conditions and drawing upon knowledge from local managers.
Northern hardwood forests occur on well to moderately well-drained, fine-textured soils across much of New England and northern New York. Species including sugar maple, white ash, and basswood are dominant on sites with enriched soils while beech, yellow birch, and sugar maple tend to be dominant on poorer sites. Stand-replacing disturbances occur every 500 years or longer, but small to medium wind, ice, insect, and disease disturbances are common. As a result, northern hardwood forests develop dense, continuous canopies of shade-tolerant trees and shade-tolerant understory plants. Northern hardwood forests are widespread across the region and occur across a variety of sites, which means that climate change will affect forests in different ways. Information from this section is summarized from a vulnerability assessment for regional forests. Northern hardwood forests occur on well to moderately well-drained, fine-textured soils across much of New England and northern New York. Species including sugar maple, white ash, and basswood are dominant on sites with enriched soils while sugar maple, beech, and yellow birch tend to be dominant on poorer sites. Small to medium wind, ice, insect, and disease disturbances are common whereas stand-replacing disturbances occur every 500 years or longer. As a result, northern hardwood forests develop dense, continuous canopies of shade-tolerant trees and shade-tolerant understory plants. Northern hardwood forests are widespread across the region and occur across a variety of sites, which means that climate change will affect forests in different ways. Information from this section is summarized from a vulnerability assessment for regional forests. Site-level factors could make a northern hardwood stand more or less vulnerable to climate change, and the considerations below include some site-level factors that could increase or reduce risk. Climate Change and Northern Hardwood Forest Ecosystems
Climate Change and Northern Hardwood Forest Ecosystems
Climate Impacts
Adaptive Capacity of Northern Hardwood Forests
Site-level Considerations for Northern Hardwoods
Site-level consideration
High-risk condition
Low-risk condition
Overstory Composition
The site is dominated by a few species that are vulnerable to climate change impacts and/or invasive pests.
The site has a diverse mix of tree species, and these species are expected to be adapted to future conditions.
Regeneration
There are barriers to regeneration on site (e.g., deer browse, invasive plants, earthworms, and nutrient limitations).
Tree regeneration on site is not limited by competing vegetation or browse.
Understory Competition
Invasive or nuisance plant species (e.g., beech, hay-scented fern,) are present and competing with native species.
Invasive plant species are not present or are limited, and native vegetation is diverse.
Soils
The site has low soil fertility or past land use or earthworms.
The site has high soil fertility and soils remain relatively undisturbed by past management or invasives.
Hydrology and Infrastructure
Natural hydrology at the site is disrupted by ditches, roads, culverts, or other alterations.
Natural hydrology has been maintained at the site and infrastructure can tolerate impacts from extreme flooding and drought.
Insects and Disease
The site is infested with damaging insects and pathogens or is near known detections.
The site is not infested and is distant from known infestations damaging insects and pathogens.
Adaptation Actions for High-Risk Site Conditions in Northern Hardwoods.
A variety of actions are available for responding to climate change. This section presents examples of adaptation actions to address high-risk conditions in northern hardwood forests. For each example, the corresponding adaptation approaches from the Forests or Forested Watersheds Adaptation Menus are identified in parentheses Adaptation demonstration projects that use these actions are also highlighted to help as a starting point for managers who are exploring actions to take on the lands that they manage.
- Use intermediate treatments, including release and thinning treatments, to encourage tree diversity, vigor, and seed production of climate-adapted and non-host species (Approach 9.1, 9.3).
- Retain threatened canopy species, like ash and beech, particularly those exhibiting resistance to stressors as potential sources of resistant genotypes (Approach 5.3, 8.2).
- Use regeneration methods, such as group selection and irregular shelterwoods, that retain diverse seed sources and provide regeneration environments for a wide range of species (Approach 5.2, 5.3, 10.2).
- Reduce invasive species and beech on-site using mechanical or chemical methods (Approach 2.2).
- Clean equipment to minimize the introduction of invasives (Approach 2.2).
- Apply release treatments following regeneration harvests to reduce the abundance of beech and non-native species (Approach 9.3).
- Plant a diversity of native tree species, including those expected to tolerate future climate conditions (Approach 9.1, 9.2, 9.6).
- Include tree species from slightly farther south in tree plantings as a form of range expansion (Approach 9.7).
- Retain tops in harvest openings or use slash walls where possible to reduce browse impacts (Approach 2.3).
- Reduce invasive species and beech on-site using mechanical or chemical methods (Approach 2.2).
- Clean equipment to minimize the introduction of invasives (Approach 2.2).
- Apply release treatments following regeneration harvests to reduce the abundance of beech and non-native species (Approach 9.3).
- Retain tops and enhance downed woody material during harvests (Approach 1.1).
- On unenriched sites, use group selection with large group sizes (0.3-1 ac), low-density shelterwood, or patch clearcutting to increase the abundance of tree species with high-quality leaf litter (pin cherry, aspen, ash, birch) (Approach 5.2, 6.1).
- On earthworm-impacted sites, protect and release sugar maple advance regeneration during regeneration harvests to sustain option on site (Approach 5.3).
- Use erosion control mixes from stump grindings to help stabilize soils (Approach 1.1)
- Repair or upgrade culverts or crossings to accommodate increased flows (Forested Watershed Menu 6.1).
- Use modifications for road and drainage infrastructure (water bars, portable skidder bridge) to conduct summer harvest (Forested Watershed Menu 6.1, 6.2)
- Restore large woody material to riparian areas to dissipate streamflow energy (Forest Menu 1.3, Forested Watershed Menu 5.3).
- Retain canopy trees exhibiting resistance to insects and diseases on-site, such as those that do not show symptoms of beech bark disease or emerald ash borer infestation(Approach 2.1).
- Use regeneration harvests that sustain options for threatened species on site as mature canopy trees and in the regeneration layer (e.g., group selection, irregular shelterwood, and patch selection with reserves for white ash; Approach 2.1, 5.3).
- Encourage a diverse mix of canopy species through intermediate treatments and regeneration harvests (Approach 9.1, 9.2)
- Plant species share similar ecological and cultural values to threatened species, which are also future climate-adapted (Approach 9.1, 9.7).
- Plant species sharing similar ecological and cultural values to threatened species, which are also future climate-adapted (Approach 9.1, 9.7).
Silvicultural Strategies in Northern Hardwood Forests
The following video provides more information on adaptation in Northern Hardwoods. View the presentation, "Exploring Silvicultural Strategies in Vermont’s Changing Forest – Northwoods" by Dr. Tony D’Amato, Rubenstein School of Environment and Natural Resources, University of Vermont
Adaptation in Action
-
Increasing Opportunities for Sustainable Timber Harvest on the Atlas Timberlands
-
Setting Northern New York Forests on Climate-Adapted Trajectories
-
Audubon Vermont: Protecting Forest Bird Habitats in a Changing Climate