Climate Impact on the Eastern Hemlock

Global climate change is changing the abundances, range, and interactions of native as well as invasive species. Dr. Carole Cheah, an entomologist with the Connecticut Agricultural Experiment Station, will share her extensive body of research on different stressors and their impacts on eastern hemlock health in the context of a rapidly changing climate.

The eastern hemlock is an important tree species in New England forests. Hemlocks, while not a highly sought-after timber product, are an important part of a healthy forest. Eastern hemlocks have dense evergreen foliage and grow along streams and play an important role in the water cycle by regulating stream flow year-round. Their shade also helps control stream temperatures and helps aquatic animals, like brook trout, that require cold water for survival. These trees play an important role in the animal and plant communities of our forests.

The hemlock woolly adelgid, an invasive insect introduced to eastern North America from Japan, has caused serious damage to eastern hemlocks here in New England and beyond.  But it’s spread has been slowed by its vulnerability to extreme cold winter temperatures. Traditional predictions are that rising winter temperatures in the future due to climate change are likely to remove the conditions currently limiting the adelgid.  Dr. Cheah will share evidence from her long-term studies of 25 years with the eastern hemlock ecosystem that have surprisingly different conclusions for hemlock woolly adelgid range expansion that offer hope for the perpetuation of eastern hemlocks in the Northeast.