Forested watershed

These forests are also prevalent across the region on a wide variety of soils and landforms. Not all areas are expected to be affected equally, and in general, areas that are north-facing, at higher elevations, or are farther north in the region are expected to undergo less change and may continue to support spruce-fir forest in the future. At the same time, spruce-fir forests that are farther south may have a reduced capacity to cope with future conditions, particularly where past land use or management has already impaired the system.

These forests tend to have relatively low diversity and be dominated by a relatively small number of northern and boreal species. Forests with lower species diversity may be more vulnerable. Further, management often favors the hardwood component in these forests, and additional stress or disturbance may continue to shift forest composition toward hardwood species.

These species all tolerate a fairly wide range of conditions. Multiple forest impact models tend to agree that these species are more likely to increase or remain stable in suitable habitat and biomass under a mild climate scenario, but these species may fare worse under a hotter, drier future climate scenario.

These are northern species near their southern range limits in New England and northern New York. Multiple forest impact models tend to agree that these species are more likely to decline in suitable habitat and biomass across a range of climate scenarios by the end of the century. Impacts from climate change are projected to be less severe in the northern part of the region allowing the dominant species to persist in some areas.

This forest type is strongly associated with cold climates and is widespread across northern New England and New York. These forests may be particularly susceptible to warmer temperatures and longer growing seasons. The future climate is expected to be less suitable for the northern and boreal conifer species, while more favorable for many hardwood species that are a component of these forests. Enhanced stress and changes in competitive relationships among tree species are likely to alter forest composition.

Changes in snowfall amount and duration throughout the assessment area may change the wintertime foraging behavior for herbivores such as moose, white-tailed deer, and snowshoe hare. Moose are expected to be negatively affected by numerous changes in the future, including heat stress and increased parasitism from winter ticks. In contrast, deer may benefit in many parts of the region as warmer winter temperatures and reduced snow depth increase access to winter forage.

Many insect species are limited by extremely cold temperatures, and evidence suggests that several insect species may increase in a warmer climate, including the balsam woolly adelgid. At the same time, the native spruce budworm may be reduced under the warmer conditions expected in the future as its range shifts farther northward into Canada.

The presence of this forest at high latitudes and elevations presents little opportunity for the community to move to new habitats. This is particularly true in southern New England, where this community is highly fragmented and exists primarily on isolated mountaintops. A temperature increase of 5 °F could eliminate all habitat from Massachusetts. Less substantial impacts are projected to be less in the northern part of the assessment area, such as in Maine, where the dominant species are expected to persist in some areas.

This type is strongly associated with the coldest and most extreme climates. Reductions in snowpack may reduce soil moisture availability in the spring or increase the probability of root damage during freeze-thaw events. Increases in extreme storm events may lead to enhanced tree mortality from disturbance.