Non-Forested Wetlands

Deer use conifer-rich lowlands to avoid severe winter weather, so even low deer populations can be damaging. Changes in herbivore populations may have substantial effects on forest growth and composition. Browsing pressure may increase on hardwood species as northern white-cedar and other conifers decline.

Climate change may amplify several major stressors that are already affecting this forest system. Warmer temperatures may dampen the effects of the eastern spruce budworm, but allow balsam woolly adelgid and hemlock woolly adelgid to increase and spread more easily . Tree susceptibility to insect infestations are expected to increase as trees become moisture-stressed. Studies suggest that insect pests may increase in northern forests due to increased metabolic activity in active periods and increased winter survival.

Peak streamflow is expected to shift to earlier in the spring and increased precipitation is expected to intensify spring peak flows. An increase in intense precipitation is likely to result in more frequent flooding. Reduced precipitation in the summer and fall is may result in drier conditions and a lower water table, which would negatively affect rain-fed ecosystems.

This community has relatively few species compared to other forest communities and many of them are threatened by insect pests. As the current dominant species decline, the functional identity of this ecosystem will be greatly challenged. Some tree species may be more likley to persist or increase through the end of the century , such as red maple.

Multiple forest impact models tend to agree that many species are more likely to decline in suitable habitat and biomass across a range of climate scenarios by the end of the century. These are largely northern species near their southern range limits in the Mid-Atlantic region. Yellow birch and red maple are projected to decline under the high emissions scenario only. Common associate species, such as American beech, American elm, and white ash, may not be able to increase as much as projected due to substantial impacts from insects and diseases.

This forested wetland community is limited to areas that remain wetter and cooler than adjacent uplands. They occur in a range of hydrologic and soil conditions which are expected to be disturbed through increased severe precipitation events and flooding, increased risk of drought, and changes in the water table or relative influence of precipitation versus groundwater. Historical land use has already resulted in altered hydrology in some locations; this legacy will likely continue to stress the system as the precipitation regime changes.

These forests tend to have fairly high species diversity, which may increase the number of ways in which the ecosystem can adjust to changing conditions while maintaining important ecosystem functions. Many tree species are often present, representing a broad mix of tolerances and reproductive strategies.

There are many invasive plant species, insect pests, and forest diseases that have negative impacts on central oak-pine forests, many of which are expected to increase through the direct and indirect effects of climate change. Invasive species such as buckthorn, honeysuckle, and garlic mustard are already threats to some forests, and invasive species are expected to increase in abundance under climate change, particularly where forests are disturbed. Invasive species can also impair regeneration of native species.

Changes in snowfall amount and duration throughout the assessment area may change the wintertime foraging behavior for herbivores such as white-tailed dee. Where present, deer may benefit in many parts of the region as warmer winter temperatures and reduced snow depth increase access to winter forage.

Studies suggest that insect pests may increase due to increased metabolic activity in active periods and increased winter survival. Insect pests, such as spongy moth (Lymantria dispar) and southern pine beetle are expected to cause more frequent and severe damage under climate change, and new pests present unknown risks. Trees stressed by heat, drought, or disturbance are also typically more vulnerable to insect pests and diseases. Damage from existing native pests such as two-lined chestnut borer could combine with drought stress, for example.