Forest [FAR1]

Heavy precipitation events have increased substantially in number and severity in the across the Northeast over the last century, and many models agree that this trend will continue over the next century. Extreme precipitation events could lead to more frequent or severe flooding and an increase in soil erosion. Monthly precipitation in the Northeast is projected to be about 1 inch greater for December through April by end of century (2070–2100) under a high emissions scenario.

All global climate models agree that there will be changes in precipitation patterns across the assessment area, but there is large variability among projections of future precipitation. Most climate models project increases in annual precipitation. Seasonally, winter and spring are also generally projected to have increases in precipitation during the next century. Projections of summer and fall precipitation for this region vary, with many models projecting decreased precipitation or only very slight increases.

Evidence at both global and local scales indicates that growing seasons have been getting longer, and this trend is projected to become even more pronounced over the next century. Warmer temperatures will result in fewer days with minimum temperatures below 32°F and a shorter freeze-free season.

All global climate models project that temperatures in New England and northern New York will increase over the next century as a result of continued increases in atmospheric greenhouse gas concentrations.

Drier conditions could also increase the risk of duff fire, previously not a threat except after extreme anthropogenic disturbances.

Complex topography may provide cool pockets of habitat, such as in high-elevation valley bottoms, where this ecosystem would be likely to persist.

Insect pests such as the hemlock and balsam woolly adelgids currently affect this ecosystem and have the potential to increase when winter temperatures no longer limit populations.

Although this ecosystem generally receives the highest rainfall in the Central Appalachians, a decrease in precipitation, combined with higher temperatures, may negatively impact spruce regeneration.

Changes in winter processes could affect this high-elevation ecosystem more than others; interacting effects of reduced snow cover (warm temperatures) or increased snow cover (lake effect) would alter soil freezing conditions.

Suitable habitat for this ecosystem is already limited to the highest elevations in the Central Appalachians and the range of this ecosystem may contract as climate change forces species upward. This ecosystem is dependent on very moist conditions, and persists only in the coolest, wettest, and highest elevation sites in mountainous sections.