Adaptation Actions for Northern Hardwood Forests

Northern hardwood forests are already being affected by climate change, which creates challenges for sustaining the ecological, economic, and cultural benefits that these forests provide. Many adaptation management actions can address these key challenges based on site-specific conditions and drawing upon knowledge from local managers.

Northern Hardwood Forest Ecosystems

Northern hardwood forests occur on well to moderately-well-drained, fine-textured soils. 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.

Climate Change and Northern Hardwood Forest Ecosystems

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.

Climate Impacts

• Droughts could increase stress in northern hardwood forests and also raise the risk of insects, diseases, and wildfires on drier sites.
• Increases in extreme weather events, including windstorms and high rainfall periods, may lead to more frequent or widespread windthrow and flooding impacts to infrastructure.
• Reduced snow cover and more frequent freeze-thaw events could exacerbate hardwood decline and limit harvest operations.
• Forest tent caterpillars, spongy moths, and other insects may cause more damage in forests stressed by altered climate conditions. New insects such as emerald ash borer and hemlock woolly adelgid may be able to persist where introduced, since temperatures may not be consistently cold enough to kill these insects.
• Deer populations may be able to increase with warmer winters, which may further limit the regeneration of hardwood species.

Adaptive Capacity of Northern Hardwood Forests

• Northern hardwood forests occur across a variety of soils and landforms and contain many species, and therefore many options for this ecosystem to persist.
• Areas that are north-facing, at higher elevations, or farther north in the region are expected to undergo less change.
• In more northern portions of the region, sites that are currently too wet or cold to support northern hardwoods may become more suitable habitats for this species over time.
• Stands with low species and structural diversity may have lower adaptive capacity.

Site-level Considerations for Northern Hardwoods

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.